JP5164870B2 - Welding method of upper and lower T-shaped joint, upper and lower T-shaped welded joint, and welded structure using the same - Google Patents

Description

  The present invention relates to a welding method for an upper and lower T-shaped joint for welding a thin flat plate to the upper and lower surfaces of the standing plate, an upper and lower T-shaped welded joint, and a welded structure using the same.

  A through-welding method for T-shaped joints using a high energy density electron beam or laser beam has been proposed.

  For example, in the through-welding method for a T-shaped joint described in Patent Document 1, a surface in contact with the upper plate of the lower plate is formed in a concave shape, and an electron beam is irradiated from the surface of the upper plate to cause the weld metal of the upper plate to be in the concave shape. It is disclosed to take part. Targeting thick T-shaped joint members that are difficult in the conventional welding process, the upper plate can be melted and penetrated by electron beam welding and easily melted to the lower plate side.

  In the welding method described in Patent Document 2 and a structure joined using the welding method, a vehicle body frame having a joint structure that is difficult by conventional arc welding is used as a target for a member having a substantially plate-like portion as a joining portion. It is disclosed that through welding processing is performed using a predetermined through welding means (laser welding means, electron beam welding means) from a member surface opposite to a surface on which the other member abuts while abutting a joint portion of the member. ing. Since the laser welding is performed by irradiating a member with a laser beam condensed and optically densified by an optical lens or the like to melt the member, the above-described through welding is possible.

  In the hollow material of aluminum alloy and the manufacturing method thereof described in Patent Document 3, a solid extruded shape having a cross-sectional comb shape, a plate material facing the comb teeth of the solid shape, and the comb teeth of the solid shape It is disclosed that the contact portion between the front end portion of the plate and the plate member is welded. Further, it is disclosed that a plate material is placed facing the comb tooth portion of the solid shape member and a contact portion between the tip portion of the solid shape member and the plate material is welded. The contact portion (T-shaped joint portion) between the tip portion of the comb tooth portion of the solid shape member and the plate member is welded mainly by laser welding. Patent Document 3 describes that MIG welding or TIG welding may be used instead of laser welding. In MIG welding, in order to melt and bond to the lower comb tooth portion, a hole is provided in the upper plate in advance, and from this hole portion, plug welding (MIG arc spot welding) is performed to join the lower comb tooth portion. Like to do.

  On the other hand, a deep penetration TIG welding method using a flux cored wire is disclosed in the following documents.

  For example, in the TIG welding method described in Patent Document 4, a flux-cored wire including a flux containing 6% by mass or more of a metal oxide is used as a filler material, and the metal oxide is added to a molten metal by 0.05. It is disclosed that TIG welding is performed while supplying -3 g / min. Further, a deep penetration portion is obtained by TIG welding while supplying a predetermined amount of a flux-cored wire containing 6% or more of a metal oxide. In particular, a measurement result of a penetration depth obtained by performing a one-side penetration welding test on a 9 mm-thick I-type butt joint from the surface side is shown.

In the flux-cored wire for TIG welding described in Patent Document 5, the flux is composed of SiO ₂ and Cr ₂ O _{3 in} order to obtain a deep penetration portion by application to welding of an I-type joint, and the mixing ratio is SiO _2. Is 20 to 80% by weight and Cr ₂ O ₃ is 20 to 80% by weight, and it is disclosed that this flux-filled wire is filled in a ratio of 5 to 25% by weight. Test results of bead-on-plate welding to a flat plate of 8 mm thick stainless steel are disclosed.

  In the TIG welding method described in Patent Document 6, it is disclosed that an arc is generated on the center line of the second member on the groove front side of the first member and welding is performed while an alternating magnetic field is applied to the welded portion. While applying an alternating magnetic field during arc welding, the melted portion is agitated to form back beads on the left and right back portions of the T-shaped joint.

In the TIG welding apparatus and method described in Patent Document 7, the first shield gas made of an inert gas is caused to flow toward the work piece so as to surround the outer periphery of the electrode, and at the periphery of the first shield gas. It is disclosed that welding is performed while flowing a second shield gas containing an oxidizing gas toward an object to be welded, so that the oxygen concentration of the weld metal portion is in the range of 70 to 220 wt.ppm. Patent Document 7 discloses an oxidizing gas (O ₂ gas or CO ₂ gas) and an inert gas based on the relationship between the oxygen concentration or carbon dioxide concentration of the second shield gas and the melting width and depth of the weld metal part. It is disclosed that a mixed gas with (Ar gas) is caused to flow through the arc welding portion to increase the penetration depth.

  Patent Document 8 discloses forming a T joint by friction stir welding. The friction stir welding method is a method in which a friction stir probe is inserted to friction stir weld an aluminum joint material of a low melting point material, and the aluminum joint material is solid-phase joined (state below the melting point) using the probe. To be joined). This friction stir welding method joins one workpiece and the other workpiece in a softened state without melting the material. That is, in Patent Document 8, a groove is provided on the lower surface of the first workpiece, the second workpiece is fitted into the groove, and the friction stir probe is caused to reach the flesh of the second workpiece from the upper surface side of the first workpiece. It is disclosed that a T joint is formed by friction stir welding of a first work and a second work.

  On the other hand, Patent Document 9 discloses a double-sided welded portion having a penetration shape fused at the center of the plate thickness by non-consumable electrode type arc welding performed from both the front and back sides of the I-type butt joint portion coated with a penetration accelerator. Is disclosed. It is disclosed that welding is applied from both the front and back sides after applying a penetration accelerator to the I-type butt surface.

JP-A-63-203286 (particularly, page 2, upper left column, line 16 to page upper right column, line 4, FIG. 1) JP 2003-334680 A (in particular, paragraphs 0029 and 0030, FIG. 3) JP-A-6-23451 (particularly, paragraphs 0007 to 0010, FIGS. 1 and 2) JP 2001-219274 A (particularly paragraphs 0009 and 0010) JP 2001-1183 A (particularly paragraphs 0006 to 0008) JP 59-13577 (in particular, page 1, lower right column, lines 4 to 17, line 1) JP 2004-298963 A (in particular, paragraphs 0014 to 0016, FIGS. 1, 11, and 15) JP 11-28581 A (particularly paragraphs 0012 to 0014, FIGS. 1 and 2) JP 2006-231359 A (particularly, paragraphs 0035 to 0039, FIG. 1)

  The technology disclosed in Patent Document 1 requires special environmental equipment such as a vacuum device that excludes the atmosphere and a large vacuum chamber that accommodates a member to be welded, and production costs increase with new capital investment. There's a problem. Moreover, in patent document 1, penetration welding by an electron beam becomes a keyhole-type penetration shape, and since the melting width is extremely narrow, the weld cross-sectional area is small and only a strength lower than the plate thickness strength of the member can be obtained. Keyhole type penetration welding has a problem that spatter (spattering of molten metal) is also likely to occur.

  The technique disclosed in Patent Document 2 is a keyhole-type penetration shape for laser welding and has a narrow melting width, so that the welding cross-sectional area correlated with the welding strength tends to be small. Also, spatter is likely to occur during welding. No additive wire or flux-cored wire is used for this laser welding. Furthermore, laser welding requires special equipment such as a laser transmitter, and is expensive as compared with inexpensive arc welding equipment, like electron beam welding. Patent Document 2 specifies that electron beam welding can be performed in the same manner as the laser welding, but requires special environmental equipment such as a vacuum device for eliminating the atmosphere and a vacuum chamber for housing a member to be welded. Therefore, it takes time for preparation before welding and unloading after welding, and it is not suitable for welding in a complicated shape that requires movement and rotation of the welding site.

  In the laser welding disclosed in Patent Document 3, the member is irradiated with a laser beam condensed and increased in energy density by an optical lens or the like to melt the member, so that penetration welding to the lower comb tooth portion is possible. However, since it is a keyhole-type penetration shape and the melting width is narrow, the weld cross-sectional area having a correlation with the welding strength tends to be small. Note that no additive wire or flux-cored wire is used in this laser welding. Further, the hollow material to be welded is an aluminum alloy, and it is not described that it is applied to stainless steel or low carbon steel, which are materials having completely different materials, characteristics, and melting points.

  The technique disclosed in Patent Document 4 has a problem that the penetration depth and the wire melting state vary greatly depending on the increase / decrease of the feeding amount of the flux-cored wire and the feeding direction. Further, Patent Document 4 does not assume welding of the upper and lower T-shaped joints.

  In the technique disclosed in Patent Document 5, similarly to the case of Patent Document 3, there is a problem that the penetration depth and the wire melting state vary greatly depending on the increase / decrease of the feeding amount of the flux-cored wire and the feeding direction. Patent Document 5 does not assume welding of the upper and lower T-shaped joints.

  In the technique disclosed in Patent Document 6, a groove-like groove is provided on the surface of the upper plate, and a multi-pass welding process is required for stacking up to the upper part of the groove, which is complicated. Moreover, in patent document 6, it is necessary to use a special alternating magnetic field apparatus in order to give an alternating magnetic field, and there exists a problem that manufacturing cost rises with new capital investment.

  In the technique disclosed in Patent Document 7, penetration on a flat plate not using a flux-cored wire has been studied, and welding of upper and lower T-type joints and butt joints is not assumed. Has not been studied.

  In the friction stir welding method disclosed in Patent Document 8, a welding wire (for example, a flux-cored wire or a solid wire) cannot be fed and welded to the joint portion from the outside, so that the joint surface side cannot be convex. There's a problem.

  In Patent Document 9, there is a case where minute porosity (welding defect of flux entrainment) is generated in the melted bottom portion welded after application of a penetration accelerator (flux agent mixed with a plurality of metal oxides), and the penetration shape is bent. There was a problem that insufficient melting due to misalignment or misalignment may occur. This problem is caused by melting and sealing the gap portion and its vicinity before applying the penetration accelerator, and forming a coating film thickness of 20 μm or more when applying the penetration accelerator to the joint surface after fusion sealing. Although it can be improved, new problems have arisen in that it is necessary to add work for melting and sealing, to improve the skill of brushing work of the penetration accelerator, and to increase the time. Further, Patent Document 9 does not assume welding of the upper and lower T-shaped joints.

  The present invention has been made in consideration of various aspects of the above-described technique, and is a method for welding an upper and lower T-shaped joint effective for obtaining a sound weld metal part and sufficient welding strength, and the upper and lower T-shaped welded joint. It is another object of the present invention to provide a welded structure using the same.

  A feature of the present invention that solves the above problem is a method of performing vertical T-type welding by arc welding or laser welding using a wire, and a specific penetration shape from the upper plate and lower plate surfaces to the vertical plate side by welding A welding method for forming a weld metal part.

  The arc welding in the present invention is a method in which a high-melting-point stainless steel or low-carbon steel joint material is fusion-bonded (joined in a state higher than the melting point) using the thermal energy of the arc. In order to achieve the above object, the present invention is a T-shaped joint made of a stainless steel plate in which an upper plate and a lower plate are respectively disposed on the upper and lower surfaces of a standing plate, and the thickness T1 range of the upper plate and the lower plate is within a range. 2 <T1 ≦ 6 mm, and the plate thickness T2 range of the vertical plate is 2 to 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1). In the welding method of the upper and lower T-shaped joints for welding from the respective plate surfaces arranged one by one or from the respective plate surfaces arranged in parallel to each other on the upper and lower surfaces of the standing plate to the standing plate side, the shielding gas of the inert gas A non-consumable electrode type arc welding using a shield gas supply means for flowing out a gas, or a double shield gas supply means for flowing out a shield gas containing an inert gas and a shield gas containing an oxidizing gas. Separate from the lower plate surface facing the upper side At the same time, the flux-cored wire with penetration depth promoting properties is melted separately to the vertical plate side while being fed to the arc welding part, and at least after the back surface penetrates from the upper plate surface or the lower plate surface Each melt width w of the standing plate is formed to be larger than the thickness T1 of the upper plate and the lower plate (w> T1), or the melt width w is formed to a size of w> T1, and at the same time the bead surface height C is set to Formed into a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface, or the welding cross-sectional area A of the penetration portion of the back surface of the upper plate and the lower plate or the melting width portion of the standing plate is the upper plate and the lower plate Or a weld metal part having a penetration shape in which both the melt width w and the weld cross-sectional area A are formed in a size of w> T1 and A> B1. It is provided on both upper and lower sides of the mold joint.

  Further, the present invention is a T-shaped joint made of stainless steel plates in which an upper plate and a lower plate are respectively arranged on the upper and lower surfaces of a standing plate, and the thickness T1 range of the upper plate and the lower plate is 2 <T1 ≦ 6 mm. Yes, the plate thickness T2 range of the standing plate is not less than 2 times and not more than 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1), and each plate is disposed on each of the upper and lower surfaces of the standing plate. In the welding method of the upper and lower T-shaped joints for welding from the surface or from the surface of each plate arranged in parallel to each other on the upper and lower surfaces of the vertical plate to the vertical plate side, the focal position of the laser beam irradiated to the place to be welded The laser torch is disposed so as to be shifted to the upper side from the plate surface, and laser welding by the laser beam irradiation for defocusing is performed separately from the upper plate surface or the lower plate surface facing the upper side. At the same time as performing the wire on the laser welding part Each piece is melted separately to the standing plate side while being fed, and at least the melting width w of the standing plate after passing through the back surface from the upper plate surface or the lower plate surface is the thickness of the upper plate and the lower plate. Forming larger than T1 (w> T1), or forming the melt width w to a size of w> T1, and simultaneously forming a bead surface height C 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm) Or the welding cross-sectional area A of the penetration part of the back surface of the upper plate and the lower plate or the melting width portion of the standing plate is larger than the plate thickness cross-sectional area B1 of the upper plate and the lower plate (A> B1), or the melting Penetration weld metal parts in which both the width w and the weld cross-sectional area A are formed in a size of w> T1 and A> B1 are provided on both upper and lower sides of the T-shaped joint.

  In particular, when two upper and lower plates are butt-arranged in parallel on both the upper and lower surfaces of the standing plate, the gap G is not present in each butt portion or even if it is less than 0.2 times the plate thickness T1. Is set to a small gap G range (0 ≦ G ≦ 0.2 × T1), and thereafter, non-consumable electrode type arc welding using the flux-cored wire or laser welding using the laser beam with the focus blurring is performed. It is performed separately from the upper plate surface or the lower plate surface facing the upper side, and the melting width w on the standing plate side is such that the size of w> T1 or the welding cross-sectional area A is A> B1 Or a weld metal part having a penetration shape in which both the melt width w and the weld cross-sectional area A have a size of w> T1 and A> B1 may be provided on both upper and lower sides of the T-shaped joint. .

  Further, when welding by placing one upper plate on the upper surface of the standing plate or placing two upper plates in parallel but facing each other, arc welding of the non-consumable electrode method using the flux-cored wire or the laser beam for defocusing was used. By performing laser welding, at least the melt width w from the upper plate surface after passing through the back surface is formed larger than the upper plate thickness T1 (w> T1), or the melt width w is w> T1. At the same time, the bead surface height C is formed in a convex shape 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or the weld cross section of the penetration portion on the back side of the upper plate or the melt width portion on the standing plate side A weld metal having a penetration shape in which A is formed to be larger than the upper plate thickness cross-sectional area B1 (A> B1), or both the melt width w and the weld cross-sectional area A are w> T1 and A> B1. On one side of the T-joint It can also be provided.

  Further, at least one upper plate and two lower plates are arranged on both the upper and lower surfaces of the standing plate, or a parallel arrangement of the two upper and lower plates to form the shape of the upper and lower T-shaped joints, and the non-contact method using the flux-cored wire. By performing consumable electrode type arc welding, welding is performed from the upper plate surface to the standing plate side, and the melting width w of the standing plate after passing through the back surface from the upper plate surface is larger than the upper plate thickness T1 (w> T1). ) The welded metal part of the penetration shape formed or formed with the weld cross-sectional area A of the penetration part on the back side of the upper plate or the melt width part on the vertical plate side larger than the upper plate thickness cross-sectional area B1 (A> B1) The lower plate surface is welded from the lower plate surface facing the upper side to the vertical plate side by performing the second step provided on one of the above and the non-consumable electrode type arc welding using the flux-cored wire. Standing plate melts after passing through the back The w is formed larger than the lower plate thickness T1 (w> T1), or the weld cross-sectional area A of the lower plate through-hole or the standing plate melting width is larger than the lower plate thickness cross-sectional area B1 (A > B1) It is good to have the 3rd process which equips the other of a T-shaped joint with the formed weld metal part of the penetration shape.

  Further, at least one upper plate and two lower plates are arranged on at least the upper and lower surfaces of the standing plate, or two of them are arranged in parallel to form the shape of the upper and lower T-shaped joints, and the focus-blurred laser beam is used. Welding from the upper plate surface to the standing plate side by performing laser welding, and forming the melting width w of the standing plate after passing through the back surface from the upper plate surface to be larger than the upper plate thickness T1 (w> T1), Alternatively, one of the T-shaped joints is provided with a weld metal portion having a penetration shape in which the weld cross-sectional area A of the penetration portion on the back surface of the upper plate or the melting width portion of the vertical plate is larger than the upper plate thickness cross-sectional area B1 (A> B1). The second step and welding from the lower plate surface facing the upper side to the vertical plate side by performing laser welding using the laser beam of the focal blur, and the vertical plate after the back surface penetrates from the lower plate surface The melting width w of the lower plate thickness T1 Penetration weld metal formed large (w> T1), or formed with a weld cross-sectional area A of a penetration portion on the back side of the lower plate or a melting width portion of the standing plate larger than the lower plate thickness cross-sectional area B1 (A> B1) It is good to have a 3rd process with which a part is provided in the other of a T-shaped coupling.

Further, the flux agent filled in the flux-cored wire is a powder agent in which an oxide composed of at least TiO ₂ , Cr ₂ O ₃ and SiO ₂ is mixed, and the arc welding part of the non-consumable electrode type Alternatively, the welding amount of the flux-cored wire fed to the laser welding portion by the laser beam irradiation of the focal blur is in the range of 1 g / min to 7 g / min, and the melting width w of the standing plate is the upper plate And the thickness of the lower plate is larger than the plate thickness T1 (w> T1), and the content of oxygen gas contained in the weld metal part is preferably in the range of 100 wt.ppm to 200 wt.ppm.

  Further, when using a solid wire or a strand wire instead of the flux-promoting flux-cored wire, a shield gas in which the concentration of the oxidizing gas is doubled than when the flux-cored wire is used, or the oxidizing property is used. Using shield gas with increased flow rate or flow velocity of shield gas containing gas, separately performing arc welding of the non-consumable electrode method from the upper plate surface or the lower plate surface facing the upper side, Each of the standing plates has a melting width w> T1 or a welding cross-sectional area A of A> B1, or both the melting width w and the welding cross-sectional area A are w> T1 and A>. It is good to provide the weld metal part of the penetration shape which has either of the magnitude | size of B1 in the up-and-down both sides of a T-shaped coupling.

  Further, when welding the T-shaped joint in a horizontal posture or a vertical posture, the joint member is assembled and arranged in a horizontal posture or a vertical posture, and then the non-consumable electrode type arc welding using the flux-cored wire or the focal point is used. By performing laser welding using a blurred laser beam, welding is performed from one plate surface to the vertical plate side in a horizontal or vertical posture, and then from the other plate surface in a horizontal or vertical posture. By performing two sets of arc welding using the flux-cored wire or two sets of laser welding using the focus-blurred laser beam at a position far away in time and space. The joints on the left and right sides are welded separately to the vertical plate side in the horizontal or vertical posture, and at least the melt width w of the vertical plate has a size of w> T1. It is also possible to comprise a metal part on both sides of the left and right T-shaped joint.

  In order to achieve the above object, the present invention is a T-shaped joint made of a stainless steel plate in which an upper plate and a lower plate are respectively arranged on both upper and lower surfaces of a standing plate, and the plate thickness T1 of the upper plate and the lower plate. The range is 2 <T1 ≦ 6 mm, and the plate thickness T2 range is 2 to 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1). Shielding of inert gas in each plate surface arranged one by one, or in upper and lower T-type welded joints welded from the plate surfaces arranged in parallel to each other on the upper and lower surfaces of the standing plate to the standing plate side The upper plate surface is subjected to non-consumable electrode type arc welding using shield gas supply means for flowing out gas, or double shield gas supply means for flowing out shield gas containing inert gas and shield gas containing oxidizing gas. Or separate from the lower plate surface facing the upper side At the same time, the flux-cored wire having a penetration depth promoting property is separately melted up to the vertical plate side while being fed to the arc welding part, and at least the upper plate surface or the lower plate surface to the back surface. Each melt width w of the standing plate after penetrating is formed to be larger than the plate thickness T1 of the upper plate and the lower plate (w> T1), or the melt width w is formed to a size of w> T1 and at the same time the bead surface height. C is formed in a convex shape 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or each weld cross-sectional area A of the upper plate and the lower plate through-hole portion or the stand-up plate melt width portion is defined as the upper plate and A weld metal part having a penetration shape that is larger than the plate thickness cross-sectional area B1 of the lower plate (A> B1), or has both the melt width w and the weld cross-sectional area A so that w> T1 and A> B1. With a structure equipped on both the upper and lower sides of the T-shaped joint And features.

  Further, the present invention is a T-shaped joint made of stainless steel plates in which an upper plate and a lower plate are respectively arranged on the upper and lower surfaces of a standing plate, and the thickness T1 range of the upper plate and the lower plate is 2 <T1 ≦ 6 mm. Yes, the plate thickness T2 range of the standing plate is not less than 2 times and not more than 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1), and each plate is disposed on each of the upper and lower surfaces of the standing plate. The focal position of the laser beam that irradiates the area to be welded in the upper and lower T-shaped welded joints welded from the surface of each surface to the vertical plate side. The laser torch is arranged so as to be shifted to the upper side from the plate surface, and laser welding by the laser beam irradiation for defocusing is performed separately from the upper plate surface or the lower plate surface facing the upper side. At the same time, the wire is sent to the laser welding part. While melting separately up to the standing plate side, each melting width w of the standing plate after passing through the back surface from at least the upper plate surface or the lower plate surface is determined from the plate thickness T1 of the upper plate and the lower plate. Forming a large (w> T1), or forming the melt width w to a size of w> T1, and simultaneously forming a bead surface height C in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface, or Each weld cross-sectional area A of the penetration part of the back surface of the upper plate and the lower plate or the melting width portion of the standing plate is made larger than the plate thickness cross-sectional area B1 of the upper plate and the lower plate (A> B1), or the melting width w In addition, the welding cross-sectional area A has a structure in which weld metal parts having a penetration shape in which both w> T1 and A> B1 are formed are provided on both upper and lower sides of the T-shaped joint.

  In particular, each melt width w of the standing plate is such that w> T1, or the weld cross-sectional area A is A> B1, or both the melt width w and the weld cross-sectional area A are w> T1 and A weld metal portion having a penetration shape having a size of A> B1 is formed by one pass on both upper and lower sides of the T-shaped joint by TIG arc welding using the flux-cored wire, or the laser beam for blurring the focus It is preferable that one pass is formed on each of the upper and lower sides of the T-shaped joint by laser welding using.

  Further, the upper and lower plates welded to the upper and lower surfaces of the upright plate, or the upper flat plate welded only to the upper surface of the upright plate, are at least other portions excluding the weld line portion and the vicinity thereof. By performing a non-consumable electrode type arc welding using the flux-cored wire or a laser welding using the defocused laser beam, the porous plate has a large number of holes formed in advance on the plate surface. It can also be considered that a plurality of weld line portions of the plate end surface portion or a plurality of weld line portions of the plate surface portion are welded to the standing plate side without melting the holes and the vicinity thereof.

  Further, each melting width w of the upright plate has a size of w> T1, or the welding sectional area A is a size of A> B1, or both the melting width w and the welding sectional area A are w> T1 and A welded joint having a structure in which the weld metal part having a penetration shape having a size of A> B1 is provided on either the upper or lower side of the T-type joint or one side of the T-type joint is used for nuclear equipment or thermal equipment. A welded structure incorporated in a welded structure and including a welded portion of the upper and lower T-type welded joints or a welded part of a square welded joint aligned with the upper and lower T-shaped welded joints is a high-temperature steam medium or corrosive It is good to be deployed in an environmental state in contact with the medium.

  That is, in the welding method of the upper and lower T-shaped joints of the present invention, the shield gas supply means for flowing out the shield gas of the inert gas, or the double shield for flowing out of the shield gas of the inert gas and the shield gas containing the oxidizing gas A non-consumable electrode type arc welding is separately performed from the upper plate surface or the lower plate surface opposite to the upper side using a gas supply means, and at the same time, a flux-cored wire with a penetration depth promoting property is arc-welded. Each of the melted widths w of the standing plate after passing through the back surface from at least the upper plate surface or the lower plate surface is melted separately up to the standing plate side while feeding to the part, and the upper plate and the lower plate. Convex shape (1 ≦ C ≦ 3 mm) which is larger than the plate thickness T1 (w> T1) or has the melt width w of w> T1 and the bead surface height C is 1 to 3 mm higher than the plate surface. ) Or the weld cross-sectional area A of the penetration portion of the back surface of the upper plate and the lower plate or the melted width portion of the vertical plate is larger than the plate thickness cross-sectional area B1 of the upper plate and the lower plate (A> B1), or By providing the weld metal parts of the penetration shape in which both the melt width w and the weld cross-sectional area A are formed in the size of w> T1 and A> B1 on both upper and lower sides of the T-shaped joint, It is possible to obtain weld strength (for example, tensile strength) equal to or higher than the material strength on the upper and lower T-type welded joints and the flat plate side having a weld metal portion with good quality without weld defects such as porosity. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  The non-consumable electrode type arc welding may be, for example, TIG arc welding or plasma arc welding, and it is not necessary to newly introduce special welding equipment, and an existing welding machine can be used. it can. In particular, a plurality of metals contained in the flux-cored wire are welded while feeding a flux-cored wire that promotes penetration depth to the arc welding (TIG arc welding or plasma arc welding) portion. Oxide heating reaction (for example, a chemical reaction in which oxygen is dissociated from a molten metal oxide and most of the dissociated oxygen is dissolved in the molten pool) causes convection of the molten pool (molten metal) directly under the arc. Changes depth direction and inward direction to promote penetration depth. As a result of the promotion of melting, it melts deeply from the upper plate surface to the vertical plate side, and at the same time, the vertical width w of the vertical plate can be formed larger than the plate thickness T1 (w> T1), and the vertical plate melts. The weld cross-sectional area A of the width w portion can also be formed larger than the plate thickness cross-sectional area B1 (A> B1). Furthermore, non-consumable electrode type arc welding (TIG arc welding or plasma arc welding) using the flux-cored wire melts deeply in a convection type (and heat conduction type) melting mode, and at the same time, sputter (of molten metal). There is no occurrence of scattering). Furthermore, it is not necessary to apply a flux agent to the plate surface.

The flux agent filled in the flux-cored wire is a plurality of metal oxides, for example, an oxide powder composed of components such as TiO ₂ , Cr ₂ O ₃ , and SiO ₂ . The penetration depth facilitating flux-cored wire is a special wire filled with a mixture of metal oxides of these component powders in an appropriate ratio, and promotes the penetration state by the heating reaction that occurs during arc welding. Therefore, it has the action and effect of increasing the penetration depth. Such penetration depth facilitating flux cored wire is completely different from the conventional wire (flux cored wire) containing a deoxidizer and a basic iron making agent, and promotes the penetration depth. It is a special wire filled with the metal oxide powder and is a flux-cored wire made of stainless steel having excellent corrosion resistance, and a known commercial product may be used.

On the other hand, several percent of oxidizing gas (for example, O ₂ or CO ₂ ) and inert gas (for example, Ar or the like) from the nozzle hole of the outer nozzle of the double shield supply means (for example, a welding torch having a double shield structure). A gas mixture with He) (a shielding gas containing an oxidizing gas) is passed through the molten pool portion directly under the arc and welding is performed while feeding the flux-cored wire that promotes penetration to the arc welding portion. Both the oxygen dissociated from the sex gas and the oxygen dissociated from the flux-cored wire being melted are dissolved in the molten pool. By this oxygen dissolution, the convection of the molten pool (molten metal) immediately below the arc is greatly changed in the depth direction and the inward direction, and the penetration is further deepened. As a result of promoting the penetration depth, it is possible to form a melt with the depth w of the standing plate larger than the plate thickness T1 (w> T1) at the same time as melting from the upper plate surface to the standing plate side. The weld cross-sectional area A of the melting width w of the steel plate can also be formed larger than the plate thickness cross-sectional area B1 (A> B1). As the mixed gas of the oxidizing gas (O ₂ or CO ₂ ) and the inert gas (Ar or He), a known commercial product may be used.

  The adjustment of the melting form and the melting width can be adjusted by adjusting the feeding amount of the flux-cored wire, the content of the metal oxide, or the mixing ratio, and the content of the oxidizing gas and the gas flow rate thereof can be adjusted. Adjustment is also possible by adjustment. Furthermore, it can be adjusted according to the size of welding heat input conditions such as welding current and welding speed, and a predetermined range of melting width w or welding cross-sectional area A is secured in advance depending on the plate thickness and application of the joint member. It is recommended to perform a confirmation test.

  In the welding method for the upper and lower T-shaped joints according to the present invention, the laser torch is arranged so that the focal position of the laser beam irradiated to the place to be welded is shifted upward from the plate surface, and the laser for defocusing the laser. Laser welding by beam irradiation is performed separately from the upper plate surface or the lower plate surface opposite to the upper side, and at the same time, the wires are fed to the laser welding portion and melted separately to the standing plate side. Each melt width w of the upright plate after passing through the back surface from at least the upper plate surface or the lower plate surface is larger than the plate thickness T1 of the upper plate and the lower plate (w> T1), or the melt width w is formed in a size of w> T1, and at the same time, the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) which is 1 to 3 mm higher than the plate surface; Standing board melting width Each weld cross section A of the portion is formed larger than the plate thickness cross section B1 of the upper plate and the lower plate (A> B1), or both the melt width w and the weld cross section A are w> T1 and A> B1 By providing the weld metal parts of the penetration shape formed in the size on the upper and lower sides of the T-shaped joint, as described above, the upper and lower parts having good quality weld metal parts without welding defects such as insufficient melting and undercut and porosity. A weld strength (for example, tensile strength) equal to or greater than the material strength of the T-type welded joint and the flat plate side can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

In particular, by performing laser welding using the laser beam with the focal blur, it is possible to change from a conventional keyhole-type penetration shape that melts deeply in the depth direction to a penetration shape that spreads in the width direction. As a result, the generation of metal vapor and spatter is drastically reduced, and at the same time, the melting width w of the vertical plate can be formed larger than the plate thickness T1 (w> T1), and the welding cross-sectional area A of the melting width w portion on the vertical plate side. Can be formed larger than the plate thickness cross-sectional area B1 (A> B1). As for the laser beam, any commercially available CO ₂ laser, YAG laser, fiber laser, or disk laser may be used. When the focal position of the laser beam is determined to be just hocus (distance L = 0), which is the upper plate surface, or when it is determined on the inner side of the T-shaped joint (distance L <0), it deeply melts in the depth direction. The conventional keyhole-type penetration form results in a deep penetration shape, and metal vapor and spatter frequently occur, and the penetration width in the welding width direction becomes narrow. Therefore, the vertical width of the vertical plate is set to the thickness T1 of the upper plate. Since larger (w> T1) cannot be formed, it is not preferable.

  The thickness T1 range of the upper and lower plates ((upper and lower flat plates arranged in the horizontal direction)) used for the T-shaped joint is 2 <T1 ≦ 6 mm, preferably 2 <T1 ≦ 5 mm. Therefore, it is possible to reliably melt and join from the plate surface to the upright plate side, and to obtain a weld metal part and an upper and lower T-shaped welded joint having a predetermined shape of sound penetration. Further, by setting the range of the plate thickness T2 of the upright plate to be not less than 2 times and not more than 5 times the plate thickness T1 of the upper plate (2 × T1 ≦ T2 ≦ 5 × T1), the weld line on the upper plate side to be welded Or, even if there is a slight misalignment in the alignment between the welding line on the lower plate side and the vertical plate side, the weld metal part having a sound penetration shape without melting and sagging on the end surface part on the vertical plate side and the upper and lower T A mold welded joint can be obtained.

  If the plate thickness T1 of the upper plate and the lower plate is less than 2 mm, welding deformation due to excessive melting tends to increase. On the contrary, if the plate thickness T1 of the upper plate and the lower plate is larger than 6 mm, it is difficult to melt from the upper or lower plate surface through the back surface to the vertical plate side and the melting width w of the vertical plate is sufficient. It becomes difficult to form in size. Forcibly melting requires a high-power welding device, and welding deformation due to excessive melting tends to increase, which is not preferable. On the other hand, when the plate thickness T2 on the standing plate side is thinner than twice the plate thickness T1 on the upper plate and the lower plate, for example, the welding line on the upper plate side to be welded or the welding line on the lower plate side and the standing plate side When there is a misalignment in alignment, melting is likely to occur at one end surface portion on the standing plate side, or the penetration is likely to be uneven or distorted. On the other hand, if the plate thickness T2 of the upright plate is greater than 5 times the plate thickness T1 of the upper plate and the lower plate, the ratio of the melt width w on the upright plate side and the weld cross-sectional area A to the plate thickness T2 on the upright plate side decreases. In addition, the plate thickness balance with the plate thickness T1 of the upper plate and the lower plate is deteriorated, and the weight of the material itself is increased.

  When two upper and lower plates are butt-arranged in parallel on both the upper and lower surfaces of the upright plate, there is almost no gap G in each butt portion, or even if there is almost no gap G, it is smaller than 0.2 times the plate thickness T1. Set the gap G range (0 ≦ G ≦ 0.2 × T1), preferably within the range of 0 ≦ G ≦ 0.1 × T1, which is less than 0.1 times, so that the assembly accuracy and positioning accuracy This can remove one of the factors that can adversely affect weld quality (eg, uneven penetration, uneven bead shape, undercut, etc.). Then, after the end of the butt arrangement, non-consumable electrode type arc welding using the flux-cored wire or laser welding using the defocused laser beam is performed on the upper plate surface or the lower plate facing the upper side. Each of the standing plates has a melting width w such that w> T1, or the welding cross-sectional area A is A> B1, or the melting width w and the welding cross-sectional area A. By providing the weld metal parts of the penetration shape having both of the sizes of w> T1 and A> B1 on both the upper and lower sides of the T-shaped joint, as described above, welding such as insufficient melting, undercut and porosity Welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints and the upper and lower plates having a weld metal part with good quality without defects can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  In addition, the melt width w of the standing plate is formed to a size of w> T1, and at the same time, the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface. A sound weld metal part can be obtained, and a good weld bead having a convex shape without a dent or undercut on the weld surface of the upper and lower T-shaped joints can be obtained. If the bead surface height C is less than 1 mm, an undercut is likely to occur at the bead boundary. On the other hand, if the bead surface height C is larger than 3 mm, the penetration depth becomes shallow, the bead appearance is deteriorated, and an excessive protruding portion is not preferable.

  Further, when welding by placing one upper plate on the upper surface of the standing plate or placing two upper plates in parallel but facing each other, arc welding of the non-consumable electrode method using the flux-cored wire or the laser beam for defocusing was used. By performing laser welding, at least the melt width w of the standing plate after passing through the back surface from the upper plate surface is made larger than the upper plate thickness T1 (w> T1), or the melt width w is larger than w> T1. At the same time, the bead surface height C is formed in a convex shape 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or the weld cross-sectional area A of the penetration portion on the back surface of the upper plate or the melting width portion of the standing plate is set. A weld metal part having a penetration shape formed larger than the upper plate thickness cross-sectional area B1 (A> B1), or in which both the melt width w and the weld cross-sectional area A are w> T1 and A> B1. Provided on one side of T-shaped joint By doing this, it is possible to obtain a weld strength equal to or higher than the strength of the upper and lower T-type welded joints having a good quality weld metal part and the upper plate thickness material.

  Further, at least one upper plate and two lower plates are arranged on both the upper and lower surfaces of the standing plate, or a parallel arrangement of the two upper and lower plates to form the shape of the upper and lower T-shaped joints, and the non-contact method using the flux-cored wire. By performing consumable electrode type arc welding, welding is performed from the upper plate surface to the standing plate side, and the melting width w of the standing plate after passing through the back surface from the upper plate surface is larger than the upper plate thickness T1 (w> T1). ) The welded cross-sectional weld metal part A formed or the weld cross-sectional area A of the penetration part on the back side of the upper plate or the melted width part of the vertical plate is larger than the upper plate thickness cross-sectional area B1 (A> B1). Welding from the lower plate surface facing the upper side to the upright plate side by performing the second step provided on one side and arc welding of the non-consumable electrode method using the flux-cored wire, from the lower plate surface Standing plate melt width after back surface penetration Is formed larger than the lower plate thickness T1 (w> T1), or the weld cross-sectional area A of the lower plate back surface through-hole portion or the melted width portion of the standing plate is larger than the lower plate thickness cross-sectional area B1 (A> B1) By having the third step of providing the formed weld metal part of the penetration shape on the other side of the T-shaped joint, as described above, the weld metal having good quality without welding defects such as insufficient melting, undercut and porosity. It is possible to obtain a welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints and the upper and lower plates. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  Further, at least one upper plate and two lower plates are arranged on at least the upper and lower surfaces of the standing plate, or two of them are arranged in parallel to form the shape of the upper and lower T-shaped joints, and the focus-blurred laser beam is used. Welding from the upper plate surface to the standing plate side by performing laser welding, and forming the melting width w of the standing plate after passing through the back surface from the upper plate surface to be larger than the upper plate thickness T1 (w> T1), Alternatively, one of the T-shaped joints is provided with a weld metal portion having a penetration shape in which the weld cross-sectional area A of the penetration portion on the back surface of the upper plate or the melting width portion of the vertical plate is larger than the upper plate thickness cross-sectional area B1 (A> B1). The second step and welding from the lower plate surface facing the upper side to the vertical plate side by performing laser welding using the laser beam of the focal blur, and the vertical plate after the back surface penetrates from the lower plate surface The melting width w of the lower plate thickness T1 Penetration weld metal formed large (w> T1), or formed with a weld cross-sectional area A of a penetration portion on the back side of the lower plate or a melting width portion of the standing plate larger than the lower plate thickness cross-sectional area B1 (A> B1) And the third step of providing the other part of the T-shaped joint with the upper and lower T-shaped welded joints having a good quality weld metal part free from welding defects such as insufficient melting and undercut and porosity, as described above, and A welding strength (for example, tensile strength) equal to or higher than the material strength of the upper plate and the lower plate can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

The flux agent filled inside the flux-cored wire is a powder agent in which an oxide composed of at least TiO ₂ , Cr ₂ O ₃ and SiO ₂ is mixed, and the arc welding part of the non-consumable electrode type or the The amount of welding of the flux-cored wire fed to the laser welding portion by laser beam irradiation with defocusing is in the range of 1 g / min to 7 g / min, preferably in the range of 2 g / min to 5 g / min. And the melting width w of the said standing board is formed larger than board thickness T1 of the said upper board and lower board (w> T1), and content of the oxygen gas contained in the said weld metal part is 100 wt.ppm or more By being in the range of 200 wt.ppm or less, it is possible to obtain a tensile strength equal to or higher than the material strength of the upper and lower T-type welded joints having a good quality weld metal part and the upper and lower plates.

  If the welding amount of the flux-cored wire is less than 1 g / min, the flux-cored wire will be in an irregular welding state so that it smoothly enters the molten pool, and the amount of dissolved oxygen will be too small. At the same time, the bead has an irregular shape and the depth of penetration is shallow, so that it does not melt to the standing plate side, or even if it melts to the standing plate side, the melt width w cannot be secured, which is not preferable. On the other hand, if the welding amount of the flux-cored wire is more than 7 g / min, the arc energy or laser energy is consumed for melting the wire and the amount of dissolved oxygen becomes excessive, so that the penetration depth becomes shallow. At the same time, the content of oxygen gas contained in the weld metal part exceeds an acceptable standard (for example, 200 wt. Ppm or less), and the toughness strength of the weld metal part decreases, which is not preferable. Therefore, when the content of oxygen gas contained in the weld metal part is in the range of 100 wt. Ppm or more and 200 wt. Ppm or less, the weld metal part having the same weld strength and toughness strength as the base metal strength and its upper and lower T A mold welded joint can be obtained.

  Further, when a solid wire or a strand wire is used instead of the flux-promoting flux-cored wire, a shield gas in which the concentration of the oxidizing gas is doubled than when the flux-cored wire is used or the oxidizing gas is used. By performing non-consumable electrode arc welding using a shield gas with an increased flow rate or flow velocity of the contained shield gas, a large amount of oxygen dissociated from the oxidizing gas dissolves in the molten pool, so it melts to a specific depth. It is possible to obtain a weld metal part having a sound penetration shape and its upper and lower T-shaped welded joints.

  Further, when welding the T-shaped joint in a horizontal posture or a vertical posture, the joint member is assembled and arranged in a horizontal posture or a vertical posture, and then the non-consumable electrode type arc welding using the flux-cored wire or the focal point is used. By performing laser welding using a blurred laser beam, welding is performed from one plate surface to the vertical plate side in a horizontal or vertical posture, and then from the other plate surface in a horizontal or vertical posture. By performing two sets of arc welding using the flux-cored wire or two sets of laser welding using the focus-blurred laser beam at a position far away in time and space. The joint portions on both the left and right sides are welded separately to the vertical plate side in the state of the horizontal posture or the vertical posture, and at least the melting width w of the vertical plate is a penetration shape having a size of w> T1. By providing the contact metal part on both sides of the left and right T-shaped joint, with the welding operation time can be greatly reduced, it is possible to obtain a weld metal portion and the upper and lower T-welded joint having healthy penetration shape.

  Further, in the upper and lower T-type welded joints of the present invention, shield gas supply means for flowing out the shield gas of inert gas, or double shield gas supply for flowing out of the shield gas of inert gas and the shield gas containing oxidizing gas Non-consumable electrode type arc welding is performed separately from the upper plate surface or the lower plate surface opposite to the upper side, and at the same time, a flux-cored wire that promotes penetration depth is applied to the arc welding portion. Each of the upper plate and the lower plate is melted separately up to the standing plate side while being fed, and at least the melting width w of the standing plate after passing through the back surface from the upper plate surface or the lower plate surface. Forming larger than thickness T1 (w> T1), or forming the melting width w such that w> T1, and simultaneously forming a bead surface height C 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm) Formation, also Is formed such that the weld cross-sectional area A of the penetration portion of the back surface of the upper plate and the lower plate or the melt width portion of the standing plate is larger than the plate thickness cross-sectional area B1 of the upper plate and the lower plate (A> B1) As described above, the weld metal parts in the shape of penetration formed by forming both w and the weld cross-sectional area A in the size of w> T1 and A> B1 are provided on both upper and lower sides of the T-shaped joint. It is possible to obtain a welding strength (for example, tensile strength) equal to or higher than the material strength of upper and lower T-type welded joints and upper and lower plates having welded metal parts with good quality without melting defects, undercuts and porosity. it can. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  In the upper and lower T-type welded joints of the present invention, the laser torch is arranged so that the focal position of the laser beam irradiated to the place to be welded is shifted upward from the plate surface, and the laser beam irradiation for defocusing is performed. And performing laser welding separately from the upper plate surface or the lower plate surface opposite to the upper side, respectively, and at the same time, separately feeding the laser welding portion to the vertical plate side while melting the wire, Each melt width w of the upright plate after passing through the back surface from the upper plate surface or the lower plate surface is formed larger than the plate thickness T1 of the upper plate and the lower plate (w> T1), or the melt width w is At the same time as forming w> T1, the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) which is 1 to 3 mm higher than the plate surface, or through portions or standing plates on the back surface of the upper and lower plates Of melting width part Each weld cross-sectional area A is formed larger than the plate thickness cross-sectional area B1 of the upper plate and the lower plate (A> B1), or both the melt width w and the weld cross-sectional area A are w> T1 and A> B1. As described above, a weld metal part with good quality free from welding defects such as insufficient melting and undercut and porosity is obtained. Welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints and the upper and lower plates can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  Further, each melt width w of the standing plate is such that w> T1, or the weld cross-sectional area A is A> B1, or both the melt width w and the weld cross-sectional area A are w> T1 and A weld metal portion having a penetration shape having a size of A> B1 is formed by one pass on both upper and lower sides of the T-shaped joint by TIG arc welding using the flux-cored wire, or the laser beam for blurring the focus Since one pass is formed on each of the upper and lower sides of the T-shaped joint by laser welding using, the number of work steps can be greatly reduced compared to conventional multi-pass welding and flux coating type welding. Since the amount of deformation is greatly reduced compared to the large deformation that has occurred in welding, the work for removing distortion can also be reduced.

  Further, the upper and lower plates welded to the upper and lower surfaces of the upright plate, or the upper flat plate welded only to the upper surface of the upright plate, are at least other portions excluding the weld line portion and the vicinity thereof. By performing a non-consumable electrode type arc welding using the flux-cored wire or a laser welding using the defocused laser beam, the porous plate has a large number of holes formed in advance on the plate surface. The holes are not obstructed by the holes by virtue of the structure in which a plurality of weld line portions of the plate end surface portion or a plurality of weld line portions of the plate surface portion are welded to the standing plate side, respectively, without melting the hole and the vicinity. Thus, a predetermined weld line portion can be normally welded, and an upper and lower T-shaped welded joint having a weld metal part with good quality can be obtained. Moreover, a high-temperature steam body or corrosive fluid can be incorporated into a welded structure having a structure that passes through the hole.

  Further, each melting width w of the upright plate has a size of w> T1, or the welding cross-sectional area A is a size of A> B1, or both the melting width w and the welding cross-sectional area A are w> T1 and A welded joint having a structure in which the weld metal part having a penetration shape having a size of A> B1 is provided on either the upper or lower side of the T-type joint or one side of the T-type joint is used for nuclear equipment or thermal equipment. A welded structure incorporated in a welded structure and including a welded portion of the upper and lower T-type welded joints or a welded part of a square welded joint aligned with the upper and lower T-shaped welded joints is a high-temperature steam medium or corrosive Because it is deployed in an environmental state that comes into contact with the medium, even if it is applied for a long time in a steam medium environment or a corrosive environment due to the operation of nuclear equipment or thermal equipment, the corrosion resistance and welding strength are high, so ensuring corrosion cracking, etc. Prevent event Come, it can contribute to the long life.

  As described above, according to the welding method of the upper and lower T-shaped joints of the present invention, the upper and lower T-shaped welded joints, and the welded structure using the same, good quality free from welding defects such as insufficient melting and undercut and porosity. An upper and lower T-type welded joint having a weld metal part and a welded structure using the same are obtained. Moreover, since the welding cross-sectional area A of the melt width w portion of the standing plate is ensured (A> B1), a welding strength (for example, tensile strength) equal to or higher than the material strength of the upper plate and the lower plate can be obtained. . In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs. Furthermore, even if it is applied for a long period of time in a steam medium environment or a corrosive environment due to the operation of nuclear equipment or thermal equipment, the corrosion resistance and welding strength are high, so it is possible to prevent corrosion cracking and other events and contribute to a longer life. it can.

It is explanatory drawing which shows one Embodiment of the welding procedure and penetration shape regarding the welding method of the upper and lower T type | mold joint of this invention, and its upper and lower T type | mold weld joint. It is explanatory drawing which shows other one Embodiment of the welding procedure and penetration shape regarding the welding method of the upper and lower T type | mold joint of this invention, and its upper and lower T type | mold weld joint. It is explanatory drawing which shows further another embodiment of the welding procedure and penetration shape regarding the welding method of the upper and lower T type | mold joint of this invention, and its upper and lower T type | mold weld joint. It is explanatory drawing which shows the welding method of the upper and lower T type | mold joint of this invention, and the laser welding procedure and penetration shape concerning the upper and lower T type | mold weld joint. It is explanatory drawing which shows the welding method of the upper and lower T type | mold joint of this invention, the laser welding procedure concerning the upper and lower T type | mold weld joint, and other embodiment of a penetration shape. It is an Example which shows the relationship between the welding current I according to board thickness when the welding method shown by FIG. 1 is applied, the melting width w of the standing board 3, and the penetration depth h. It is an Example which shows the relationship between the welding current I of the T-type joint when applying the welding method shown in FIG. 1, heat input Q, and penetration depth H from the upper plate surface. It is an Example which shows the relationship between the welding amount of a flux cored wire at the time of applying the welding method shown by FIG. 1, a penetration depth, and O gas content of a molten metal part. It is a perspective view of one example showing an outline of a welding structure which has a plurality of T type joints and a welding line. It is sectional drawing of the comparative example which shows the multipass welding shape of the T-shaped joint with a groove by the conventional TIG welding method. It is sectional drawing of the other comparative example which shows the multipass welding shape of the T-shaped joint with a gap by the conventional TIG welding method. It is sectional drawing of the further another comparative example which shows the multipass welding shape of the T-shaped joint with a gap by the conventional TIG welding method. It is sectional drawing of the comparative example which shows the penetration shape of the T-shaped coupling by the conventional laser welding method.

  Hereinafter, the content of the present invention will be specifically described with reference to the embodiments shown in FIGS.

Embodiment 1
FIG. 1 is an explanatory view showing an embodiment of a welding method of an upper and lower T-shaped joint, a welding procedure and a penetration shape related to the upper and lower T-shaped welded joint. That is, in the first first step 31, as shown in FIG. 1 (1), the upper and lower surfaces (both surfaces of the vertical plate) along the vertical direction with respect to the floor surface are aligned along the horizontal direction. A T-shaped joint having a top and bottom T-shape is manufactured by arranging one plate and one lower plate 1a, 1b one by one, or two upper plates and two lower plates 1a, 1b, 2a, 2b arranged in parallel. The T-shaped joint to be welded is, for example, a welded article incorporated in nuclear equipment or thermal equipment. In particular, it is made of a stainless steel material or a general carbon steel material excellent in corrosion resistance, and the thickness T1 range of the upper plate and the lower plate is 2 <T1 ≦ 6 mm. Preferably, it is further better to keep it in the range of 2 <T1 ≦ 5 mm. Further, the plate thickness T2 range of the upright plate 3 is not less than 2 times and not more than 5 times (2 × T1 ≦ T2 ≦ 5 × T1) of the plate thickness T1 of the upper plate and the lower plate. The upper and lower plates of the plate thickness T1 are arranged one by one in the horizontal direction or two in parallel butted in parallel to form a joint in a vertical T shape. The joint between the upper and lower plates 1a, 1b, 2a, 2b and the standing plate 3 in the middle thereof, with no gap G at the butted portion of the upper and lower plates 1a, 1b, 2a, 2b The surface also has almost no gap, and is positioned and arranged with relatively high accuracy. In addition, B1 described in the figure is a plate | board thickness cross-sectional area seen from plate | board thickness T1 direction of upper board and lower board 1a, 1b, 2a, 2b.

  By setting the plate thickness T1 range of the upper and lower plates 1a, 1b, 2a, 2b (upper and lower flat plates arranged in the horizontal direction) to 2 <T1 ≦ 6 mm, preferably 2 <T1 ≦ 5 mm By setting it within the range, it is possible to reliably melt and join the upper plate and the lower plate 1a, 1b, 2a, 2b from the front surface to the back plate 3 side through the back surface, and a weld metal having a good penetration shape. The upper and lower T-type welded joints 12 provided with the portions 7b and 8b on the upper and lower sides of the T-type joint can be obtained. Further, the plate thickness T2 range of the upright plate 3 is set to be not less than 2 times and not more than 5 times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (2 × T1 ≦ T2 ≦ 5 × T1). Accordingly, even if there is a slight misalignment in the alignment between the welding lines of the upper and lower plates 1a, 1b, 2a, 2b to be welded and both surfaces of the standing plate 3 in the middle thereof, the standing plate 3 It is possible to obtain the weld metal portions 7b and 8b and the upper and lower T-shaped welded joints 12 having a sound penetration shape without melting and sagging at the end face portions.

  If the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b is less than 2 mm, welding deformation due to excessive melting tends to increase. On the other hand, if the thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b is greater than 6 mm, it is difficult to melt from the upper or lower plate surface to the vertical plate 3 through the back surface. It is also difficult to form the melt width w of the plate 3 to a sufficient size. In order to forcibly melt and join, a welding apparatus with a high output is required, and welding deformation due to excessive melting of the upper and lower plates 1a, 1b, 2a, and 2b tends to increase. On the other hand, if the plate thickness T2 of the standing plate 3 is thinner than twice the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b, for example, the upper and lower plates 1a, 1b, 2a, When the position of the welding line 2b and the both sides of the standing plate 3 is misaligned, the one end surface portion of the standing plate 3 is likely to melt and sag, or the penetration is likely to be uneven or distorted. On the contrary, if the plate thickness T2 of the standing plate 3 is thicker than five times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b, the melting width w of the standing plate 3 with respect to the plate thickness T2 of the standing plate 3 and This is not preferable because the ratio of the weld cross-sectional area A is reduced, and the balance of the plate thickness T1 with the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b is deteriorated and the weight of the material itself is increased.

  In the next second step 32, as shown in FIG. 1 (2), a shielding gas of an inert gas (for example, pure Ar gas, He gas, or a mixed gas of Ar and He) from the inner periphery of the nozzle 9a. A non-consumable electrode type arc welding is performed by using a shielded welding torch 11 (shield gas supply means) that flows out of 9b, and at the same time, a flux-cored wire 4 that promotes penetration depth is fed to the arc 6 welding portion. However, the upper plate 1a, 2a is melt-bonded from the plate surface side to the standing plate 3. In particular, by this fusion bonding, at least the melt width w of the upright plate 3 after penetrating the back surface from the plate surface of the upper plates 1a, 2a is made larger than the plate thickness T1 of the upper plates 1a, 2a (w> T1), or the melting is performed. The width w is formed in a size of w> T1, and the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) higher by 1 to 3 mm than the plate surface, or the through portion of the back surface of the upper plates 1a and 2a Alternatively, the welding cross-sectional area A of the melting width portion of the upright plate 3 is formed larger than the plate thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1), or both the melting width w and the welding cross-sectional area A> w> A weld metal part 7a having a penetration shape formed to have a size of T1 and A> B1 is obtained.

  In addition, the welding cross-sectional area A of the melt width w portion of the upright plate 3 is obtained by the product (A = w × L) of the melt width w of the upright plate 3 and the weld line length L. Similarly, the plate thickness cross-sectional area B1 in the plate thickness T1 direction is obtained by the product of the plate thickness T1 of the upper plates 1 and 2 and the weld line length L (B1 = T1 × L), and the melting width w is defined as If formed so as to satisfy w> T1, the weld cross-sectional area A at that time is formed larger than the plate thickness cross-sectional area B1 (A> B1).

  The non-consumable electrode type arc welding is, for example, TIG arc welding or plasma arc welding, and it is not necessary to newly introduce special welding equipment, and an existing welding machine can be used. In particular, by performing non-consumable electrode type arc welding (TIG arc welding or plasma arc welding) using a flux-cored wire 4 that promotes penetration depth, a plurality of materials contained in the flux-cored wire 4 are contained. By a heating reaction of the metal oxide (for example, a chemical reaction in which oxygen is dissociated from the molten metal oxide and most of the dissociated oxygen is dissolved in the molten pool 7a). Metal) convection changes in the depth direction and inward direction to promote penetration depth. As a result of the promotion of melting, the upper plate 1a, 2a is melted deeply from the plate surface to the standing plate 3, and the melting width w of the standing plate 3 is larger than the thickness T1 of the upper plates 1a, 2a (w> T1). In addition, the weld cross-sectional area A of the penetration portion on the back surface of the upper plate and the melting width w portion of the vertical plate is also made larger than the plate thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1), A weld strength (for example, tensile strength) equal to or higher than that can be obtained. Furthermore, non-consumable electrode type arc welding (TIG arc welding or plasma arc welding) using the flux-cored wire melts deeply in a convection type (and heat conduction type) melting mode, and at the same time, sputter (of molten metal). There is no occurrence of scattering). Furthermore, it is not necessary to apply a flux agent to the plate surface.

  Such adjustment of the melting form and the melting width w can be adjusted by adjusting the feeding amount of the flux-cored wire 4 that promotes the penetration depth, the content of the metal oxide, or the mixing ratio. In addition, it can be adjusted according to the welding heat input conditions such as welding current and welding speed, and in advance to ensure a predetermined range of melt width w and welding cross-sectional area A according to the plate thickness and application of the joint member. It is recommended to perform a confirmation test.

The flux agent filled in the flux-cored wire is a plurality of metal oxides, for example, an oxide powder composed of components such as TiO ₂ , Cr ₂ O ₃ , and SiO ₂ . The penetration depth-promoting flux-cored wire 4 is a special wire filled with a mixture of metal oxides of these component powders at an appropriate ratio, and promotes the penetration state by the heating reaction that occurs during arc welding. Therefore, it has the action and effect of increasing the penetration depth. Such a penetration depth promoting flux-cored wire 4 is completely different in composition and action from a conventional wire (flux-cored wire) containing a deoxidizer and a basic iron making agent, and promotes the penetration depth. It is a special wire filled with the metal oxide powder, and is a flux-cored wire made of stainless steel having excellent corrosion resistance, and a known commercial product may be used.

The non-consumable electrode 5 is a tungsten electrode provided at the tip of the welding torch 11, and is commercially available such as W containing La ₂ O _3, W containing Y ₂ O ₃ and W containing ThO _2. Product electrode rods may be used. The shield gas 9b that protects the welded part of the arc 6 and the electrode 5 is an inert gas that flows out from the inner periphery of the nozzle 9a, for example, pure Ar gas or He gas, and an Ar-based mixed gas is also used. It is possible to use a commercially available gas.

  After completion of the welding in the second step 32, the joint member is turned over. Thereafter, the process proceeds to the next third step 33. That is, in the third step 33, as shown in FIG. 1 (3), a non-consumable electrode type arc is used by using a welding torch 11 (shield gas supply means) having a shield structure that flows out a shield gas 9b of an inert gas. At the same time as performing welding, while feeding the flux-cored wire 4 that promotes penetration depth to the arc 6 welded portion, the lower plates 1b, 2b facing the upper plates 1a, 2a (because the joint members are turned upside down) The corresponding lower plates 1b and 2b are melted from the plate surface to the standing plate 3 in the upper position. In particular, as in the case of the second step 32, the melt width w of the upright plate 3 after passing through the back surface from the plate surface of the lower plate 1b, 2b is larger than the plate thickness T1 of the lower plate 1b, 2b. (W> T1) formation, or forming the melt width w to a size of w> T1, and simultaneously forming a bead surface height C in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface, or below The welding cross-sectional area A of the penetration part of the plate back surface of the plates 1b and 2b or the melting width portion of the standing plate 3 is made larger than the plate thickness cross-sectional area B1 of the lower plates 1b and 2b (A> B1), or the melting width w and A weld metal portion 8a having a penetration shape in which both of the weld cross-sectional areas A are formed in a size of w> T1 and A> B1 is obtained, and two weld metal portions 7b and 8b are provided at the top and bottom of the T-shaped joint. The upper and lower T-shaped welded joints 12 are obtained.

  With such a welding construction, the upper and lower T-type welded joints 12 and the upper plate having the upper and lower weld metal portions 7a, 7b, 8a and 8b having good quality without welding defects such as lack of melting, undercut and porosity, A welding strength (for example, tensile strength) equal to or higher than the material strength of the lower plate can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  Further, the melt width w of the upright plate 3 is formed so that w> T1, and at the same time the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface. The weld metal parts 7a and 7b can be obtained, and a good weld bead having a convex shape without a dent or undercut can be obtained on the weld surface of the T-shaped joint. If the bead surface height C is less than 1 mm, an undercut is likely to occur at the bead boundary. On the other hand, if the bead surface height C is larger than 3 mm, the penetration depth becomes shallow, the bead appearance is deteriorated, and an excessive protruding portion is not preferable.

The flux agent filled in the flux-cored wire 4 is a powder agent in which an oxide composed of at least TiO ₂ , Cr ₂ O ₃ and SiO ₂ is mixed, and the arc 6 welding portion of the non-consumable electrode type The amount of welding of the flux-cored wire fed to is in the range of 1 g / min to 7 g / min, preferably in the range of 2 g / min to 5 g / min, and the melting width w of the standing plate 3 is The upper and lower plates 1a, 1b, 2a, 2b are formed to have a thickness larger than the plate thickness T1 (w> T1), and the content of oxygen gas contained in the weld metal portions 7b, 8b is 100 wt. Ppm or more and 200 wt. Equal to the material strength of the upper and lower T-type welded joints having the weld metal parts 7b and 8b with good quality on both the upper and lower sides and the plate thickness T1 of the upper and lower plates 1a, 1b, 2a and 2b. Above weld strength (example For example, tensile strength) can be obtained.

  In addition, when the welding amount of the flux-cored wire 4 is less than 1 g / min, the flux-cored wire 4 does not smoothly enter the molten pools 7a and 8a (in the molten metal) and enters an irregular welding state and dissolves oxygen Since the amount becomes too small, the weld bead has an irregular shape, and at the same time, the melt depth is shallow so that it does not melt to the standing plate 3 or even if it melts to the standing plate 3, the melt width w is secured (w > T1) This is not preferable because it cannot be performed. On the other hand, if the welding amount of the flux-cored wire 4 is more than 7 g / min, the arc energy is consumed for melting the wire and the amount of dissolved oxygen becomes excessive, so that the penetration depth becomes shallow, This is not preferable because the content of the oxygen gas contained in the weld metal parts 7b and 8b exceeds an acceptable standard (for example, 200 wt. Ppm or less) and the toughness strength of the weld metal parts 7b and 8b is lowered. Therefore, when the content of oxygen gas contained in the weld metal portions 7b and 8b is in the range of 100 wt. Ppm to 200 wt. Ppm, the weld metal portion 7b having a weld strength and toughness similar to the base metal strength. , 8b and its upper and lower T-shaped welded joints 12 can be obtained.

  The penetration depth-promoting flux-cored wire 4 can be fed from the front in the welding progress direction to the arc 6 welding portion or from the rear in the welding progress direction to the arc 6 welding portion. In particular, by feeding the tip portion of the flux-cored wire 4 that promotes the penetration depth into the molten pool, for example, a wide range of welding current (for example, 100 A to 350 A) from a small current to a large current can be obtained. Even in the case of output or in the case of a small amount of wire that is fed at a low speed, the flux-cored wire 4 can smoothly enter the melt pool 7a directly under the arc 6 and be stably melted and welded without forming large droplets. it can. At the same time, it deeply melts from the plate surface of the upper plates 1a, 2a or the plate surface of the lower plates 1b, 2b to the standing plate 3, and the melting width w of this standing plate 3 is the plate of the upper and lower plates 1a, 1b, 2a, 2b. Plates of upper and lower T-type welded joints and upper and lower plates 1a, 1b, 2a and 2b which can be formed larger than thickness T1 (w> T1) and have weld metal parts 7b and 8b of good quality on both upper and lower sides A welding strength (for example, tensile strength) equal to or higher than the material strength of the thickness T1 can be obtained.

  Further, when the T-shaped joint is welded by changing from the downward posture to the horizontal posture or the vertical posture, the joint members 1a, 1b, 2a, 2b, 3 are assembled and arranged in the horizontal posture or the vertical posture (the joint member 1a). , 1b, 2a, 2b, 3 after rotating 90 degrees counterclockwise) and then performing non-consumable electrode type arc welding using the flux-cored wire 4 (for example, the upper plate 1a, 2a side) Weld from the surface of the plate to the vertical plate 3 in the horizontal or vertical posture, and then weld to the vertical plate 3 from the other (for example, the lower plate 1b, 2b side) plate surface in the horizontal or vertical posture. Alternatively, by performing two sets of arc welding using the flux-cored wire 4, the joints on both the left and right sides are moved to the upright plate 3 in a lateral or vertical position at positions far apart in time and space. Weld each separately, less Further, by providing the weld metal portions 7a, 7b, 8a, and 8b in the shape of penetration having the melt width w of the upright plate 3 such that w> T1, the welding work time can be greatly shortened. At the same time, the weld metal portions 7b and 8b having a sound penetration shape and the upper and lower T-shaped welded joints 12 can be obtained.

  Further, as shown in FIGS. 1 (2), (3) and (4), in the upper and lower T-type welded joints of the present invention, a welding torch 11 (shield gas) having a shield structure for allowing the shield gas 9b of an inert gas to flow out. The non-consumable electrode type arc welding is performed separately from the surface of the upper plate 1a, 2a or from the surface of the lower plate 1b, 2b opposite to the upper plate 1a, 2a using the supply means). The flux-cored wire 4 that promotes the thickness is melted separately up to the standing plate 3 while being fed to the arc 6 welding portion, and at least the plate surface of the upper plate 1a, 2a or the plate surface of the lower plate 1b, 2b Each melt width w of the standing plate 3 after penetrating is formed larger than the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (w> T1), or the melt width w is larger than w> T1. At the same time as the bead surface height C Formed into a convex shape (1 ≦ C ≦ 3 mm) that is 1 to 3 mm higher than the plate surface, or welding cuts in the penetration portion of the upper plate and the lower plate 1a, 1b, 2a, 2b on the back side of the plate or the melting width portion of the vertical plate 3 The area A is formed larger than the plate thickness cross-sectional area B1 of the upper and lower plates 1a, 1b, 2a, 2b (A> B1), or both the melt width w and the weld cross-sectional area A are set as w> T1 and A>. The weld metal portions 7a, 7b, 8a and 8b having a penetration shape formed in the size of B1 can be formed into an upper and lower T-type weld joint 12 having a structure provided on both upper and lower sides of the T-type joint.

  Further, each melting width w of the standing plate 3 is such that w> T1, or the welding cross-sectional area A is A> B1, or both the melting width w and the welding cross-sectional area A are w> T1. And weld metal parts 7a, 7b, 8a and 8b having a penetration shape having a size of any of A> B1 are provided on both upper and lower sides of the T-shaped joint by arc welding of the consumable electrode method using the flux-cored wire. It can also be assumed that each pass is formed.

  This configuration eliminates the need for groove grooves and gaps, reduces the number of welding passes, eliminates the need for flux agent application, and eliminates the generation of metal vapor and spatter during welding. It is possible to weld with a melt-bonded penetration and a fusion width. As a result, as described above, the upper and lower T-type welded joints 12 and the upper and lower plates 1a and 1b having the weld metal portions 7b and 8b of good quality without welding defects such as lack of melting, undercut and porosity on the upper and lower sides. , 2a, 2b can have a weld strength (for example, tensile strength) equal to or greater than the material strength of the plate thickness T1. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

[Embodiment 2]
FIG. 2 is an explanatory view showing another embodiment of the welding method of the upper and lower T-shaped joints, the welding procedure related to the upper and lower T-shaped welded joints, and the penetration shape. The main difference from FIG. 1 is that when two upper plates 1a, 2a and two lower plates 2b, 2b are butt-arranged in parallel on the upper and lower surfaces of the upright plate 3, the butt portion between the upper plates 1a, 2a or lower This is an example of a T-shaped joint in which there is no gap G at the abutting portion between the plates 1b and 2b, and other portions and symbols are substantially the same as those in FIG.

  For example, in a T-shaped joint of a member having a long weld line, it is unexpectedly difficult to assemble in a state where there is no gap G, and there is a gap G in the butt portion between the upper plates 1a and 2a or the butt portion between the lower plates 1b and 2b. And there is no slight gap on the upper surface of the upper plate 1a, 2a and the upright plate 3 or the joint contact surface between the lower plate 1b, 2b and the lower surface of the upright plate 3. There are things to do. In particular, when the gap G is excessively large as a whole, or when the gap G changes greatly, which sometimes exceeds the allowable value, the welding quality is adversely affected (for example, uneven penetration, uneven bead shape, Cut). In order to avoid this, in this embodiment, the allowable gap G range is limited as follows.

  That is, as shown in (1) of FIG. 2, in the first first step 31, when two upper plates 1a, 2a and two lower plates 1b, 2b are arranged in parallel on the upper and lower surfaces of the upright plate 3, respectively. Even if there is almost no gap G at each butting portion, a small gap G range not more than 0.2 times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (0 ≦ G ≦ 0) .2 × T1). It is more preferable to set it within a range of 0 ≦ G ≦ 0.1 × T1, which is preferably 0.1 times or less. Further, it is preferable that the upper plate 1a, 2a and the upper surface of the upper plate 3 or the lower plate 1b, 2b and the lower surface of the upright plate 3 have almost no gap or even 0.5 mm or less. In this way, by suppressing the gap G range and the gap, assembly accuracy and positioning accuracy are increased, and one of factors that may adversely affect the welding quality can be removed.

  As described above, the T-shaped joint to be welded is, for example, a welded product incorporated in nuclear equipment or thermal equipment. Particularly, it is made of stainless steel or general carbon steel excellent in corrosion resistance, and the plate thickness T1 range of the upper plate and lower plate 1a, 1b, 2a, 2b is 2 <T1 ≦ 6 mm, and the plate thickness of the upright plate 3 The range of T2 is not less than 2 times and not more than 5 times (2 × T1 ≦ T2 ≦ 5 × T1) the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b. An upper plate and a lower plate 1a, 1b, 2a, 2b having a thickness T1 are arranged in parallel in a horizontal direction so that a joint is formed in an upper and lower T shape.

  In the next second step 32, as shown in FIG. 2 (2), when arc welding the T-shaped joint with or without the gap G, an inert gas (for example, pure Ar gas or He is used from the inner periphery of the nozzle 9a. Gas welding or non-consumable electrode arc welding using a welding torch 11 (shielding gas supply means) having a shield structure that flows out a shielding gas 9b (mixed gas of Ar and He) and at the same time promotes penetration depth The flux-cored wire 4 is melt-bonded from the surface of the upper plates 1a and 2a to the standing plate 3 while being fed to the arc 6 welding portion. In particular, by this fusion bonding, at least the melt width w of the upright plate 3 after penetrating the back surface from the plate surface of the upper plates 1a, 2a is made larger than the plate thickness T1 of the upper plates 1a, 2a (w> T1), or the melting is performed. The width w is formed in a size of w> T1, and the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) higher by 1 to 3 mm than the plate surface, or the through portion of the back surface of the upper plates 1a and 2a Alternatively, the welding cross-sectional area A of the melting width portion of the upright plate 3 is formed larger than the plate thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1), or both the melting width w and the welding cross-sectional area A> w> A weld metal part 7a having a penetration shape formed to have a size of T1 and A> B1 is obtained.

  After completion of the welding in the second step 32, the joint member is turned over. Thereafter, the process proceeds to the next third step 33. That is, in the third step 33, as shown in (3) of FIG. 2, a non-consumable electrode type arc is used by using a welding torch 11 (shield gas supply means) having a shield structure that flows out the shield gas 9b as an inert gas. At the same time as performing welding, while feeding the flux-cored wire 4 that promotes penetration depth to the arc 6 welded portion, the lower plates 1b, 2b facing the upper plates 1a, 2a (because the joint members are turned upside down) The corresponding lower plates 1b and 2b are melted from the plate surface of the upper plate) to the standing plate 3. In particular, as in the case of the second step 32, the melt width w of the upright plate 3 after passing through the back surface from the plate surface of the lower plate 1b, 2b is larger than the plate thickness T1 of the lower plate 1b, 2b. (W> T1) formation, or forming the melt width w to a size of w> T1, and simultaneously forming a bead surface height C in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface, or below The welding cross-sectional area A of the penetration part of the plate back surface of the plates 1b and 2b or the melting width portion of the standing plate 3 is made larger than the plate thickness cross-sectional area B1 of the lower plates 1b and 2b (A> B1), or the melting width w and A weld metal part 8a having a penetration shape in which both of the weld cross-sectional areas A are formed in a size of w> T1 and A> B1 is obtained, and two weld metal parts 7b and 8b are provided on both upper and lower sides of the T-shaped joint. The upper and lower T-type welded joints 12 provided are obtained.

  Even with a T-shaped joint with or without a gap G in the butt portion due to the construction of such welding, as described above, by wire welding filling and securing of the weld cross-sectional area A (A> B1). In addition, it is equivalent to the material strength of the upper and lower T-type welded joints 12 having upper and lower welded metal parts 7a, 7b, 8a, 8b having good quality without melting defects, undercuts and porosity, etc. The above welding strength (for example, tensile strength) can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

  It is most preferable to achieve the upper and lower T-type welded joints 12 having the weld metal portions 7b and 8b having a predetermined shape on both the upper and lower sides by welding one pass at a time. When surplus or undercut occurs, a second pass of welding should be added. The melting width w and the welding cross-sectional area A of the upright plate 3 have already been formed to a predetermined size (w> T1, A> B1) by the first pass welding. Therefore, when welding in the second pass, the welding of the first pass is performed so that the surface of each weld bead of the upper plate 1a, 2a or the lower plate 1b, 2b is in a predetermined range (1 ≦ C ≦ 3 mm). By reviewing the construction conditions, determining the welding conditions for the second pass, and performing arc welding of the flux-cored wire 4 feed from the bead surface part of the previous layer welding, the above-mentioned insufficient surplus and undercut are resolved. It is possible to improve the weld metal portion 7b having a weld bead with a surplus height and a penetration shape. Further, in the second-pass welding, it is possible to use a solid wire or a strand wire instead of the flux-cored wire 4, and it is possible to eliminate the above-mentioned insufficient filling and undercut.

  Further, in the case of a T-type joint without the lower plates 1b and 2b, the welding in the third step 33 is not necessary, and the upper plates 1b and 2b may be welded to the standing plate 3 by performing arc welding in the second step. . That is, when the upper plate 1a, 2a is placed on the upper surface of the upright plate 3 or two are butt-arranged and welded in parallel, as shown in (2) of FIG. 1 and (2) of FIG. By performing non-consumable electrode type arc welding using the flux-cored wire 4, the melting width w of the upright plate 3 after passing through the back surface from the plate surface of the upper plates 1a, 2a is larger than the upper plate thickness T1 (w> T1) forming or forming the melt width w to a size of w> T1, and at the same time forming a bead surface height C to be 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or of the standing plate 3 The weld cross-sectional area A of the melt width w is formed larger than the upper plate thickness cross-sectional area B1 (A> B1), or both the melt width w and the weld cross-sectional area A are w> T1 and A> B1. The weld metal parts 7a and 7b having a penetration shape formed on the T-type joint are provided on one side. It is good to do so. Accordingly, the weld strength (for example, tensile strength) equal to or higher than the strength of the upper and lower T-type welded joints 12 and the upper plate thickness material having the weld metal portion 7b having good quality without welding defects such as insufficient melting, undercut and porosity. Can be obtained.

[Embodiment 3]
FIG. 3 is an explanatory view showing another embodiment of the welding method of the upper and lower T-shaped joints, the welding procedure related to the upper and lower T-shaped welded joints, and the penetration shape. The main difference between FIG. 1 and FIG. 2 is that a double shield structure welding torch 13 (double shield gas supply means) that flows out a shield gas containing an inert gas and a shield gas containing an oxidizing gas is used. This is to perform non-consumable electrode type arc welding. The shape of the T-shaped joint and the penetration shape of the welded portion are substantially the same as those in FIGS.

That is, as shown in (2) of FIG. 3, a double shield structure welding torch 13 (double shield gas supply means) in which an inner tube and an outer tube are coaxially arranged is used, and an outer nozzle 10a. A mixed gas 10b (shield gas containing oxidizing gas) of several percent oxidizing gas (for example, O ₂ or CO ₂ ) and inert gas (Ar or He) is allowed to flow out from the nozzle hole of the nozzle, and at the same time, the inner nozzle A shielding gas of inert gas 9b (Ar or He) is caused to flow out from the nozzle hole 9a. In this double shield gas atmosphere, the non-consumable electrode type arc welding is performed, and at the same time, the flux-cored wire 4 having a penetration depth promoting property is fed to the arc 6 welding portion, while the plates of the upper plates 1a and 2a. It melt-bonds from the surface to the standing board 3. In particular, as described above, by this fusion bonding, the melting width w of the upright plate 3 after passing through the back surface from the plate surface of the upper plate 1a, 2a is made larger than the plate thickness T1 of the upper plate 1a, 2a (w> T1). Alternatively, the melt width w is formed so that w> T1 and at the same time the bead surface height C is 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or the upper plates 1a and 2a The weld cross-sectional area A of the through portion on the back surface or the melted width portion of the upright plate 3 is formed larger than the plate thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1), or the melt width w and the weld cross-sectional area A weld metal portion 7a having a penetration shape, both of which are formed in the size of w> T1 and A> B1, is obtained.

For example, a mixed gas 10b (shield gas containing oxidizing gas) of several percent oxidizing gas (for example, O ₂ or CO ₂ ) and inert gas (for example, Ar or He) is applied to the molten pool portion directly under the arc. When the flux-cored wire 4 that promotes penetration is fed to the arc 6 welding portion while flowing, both oxygen dissociated from the oxidizing gas and oxygen dissociated from the flux-cored wire 4 during melting Dissolves in the molten pool. By this oxygen dissolution, the convection of the molten pool 7a (molten metal) immediately below the arc 6 is greatly changed in the depth direction and the inward direction, and the penetration is further deepened. As a result of promoting the penetration depth, from the surface of the upper plates 1a, 2a to the standing plate 3, the melting width w of the standing plate 3 is larger than the thickness T1 of the upper plates 1a, 2a (w> T1). In addition, the welding cross-sectional area A of the melting width w portion of the upright plate 3 can also be formed larger than the thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1). The non-consumable electrode type arc welding (TIG arc welding or plasma arc welding) using the flux-cored wire 4 and the welding torch 13 having the double shield structure is deep in a convection type (and heat conduction type) melting mode. At the same time as melting, there is no spatter (spatter of molten metal). Furthermore, it is not necessary to apply a flux agent to the plate surface.

Incidentally, the shielding gas 10b of a gas mixture of an oxidizing gas (O ₂ and CO ₂₎ and inert gas (Ar or He) is already may be used a known commercial products. Further, a welding shield torch 13 having a double shield structure may be used as a method of causing the shielding gas 9b of inert gas and the shielding gas 10b containing oxidizing gas to flow out.

  Further, the adjustment of the melting form and the melting width can be adjusted by adjusting the feeding amount of the flux-cored wire 4, the content of the metal oxide or the mixing ratio, and the content of the oxidizing gas, Adjustment is also possible by adjusting the gas flow rate. Furthermore, it can be adjusted according to the size of welding heat input conditions such as welding current and welding speed, and a predetermined range of melting width w or welding cross-sectional area A is secured in advance depending on the plate thickness and application of the joint member. It is recommended to perform a confirmation test.

  In the first first step 31, as shown in (1) of FIG. 3, the upper plate along the horizontal direction and the upper and lower surfaces (both standing plate) along the vertical direction with respect to the floor surface Produces T-shaped joints that are arranged in a T-shape by placing the lower plates 1a, 1b, 2a, 2b one by one, or placing the upper and lower plates 1a, 1b, 2a, 2b side by side in parallel. To do. As described above, the T-shaped joint to be welded is, for example, a welded product incorporated in nuclear equipment or thermal equipment. The plate thickness T1 of the upper and lower plates 1a, 1b, 2a, and 2b is 2 <T1 ≦ 6 mm. Preferably, it is further better to keep it in the range of 2 <T1 ≦ 5 mm. The plate thickness T2 range of the upright plate 3 is not less than 2 times and not more than 5 times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (2 × T1 ≦ T2 ≦ 5 × T1), The upper plate and the lower plate 1a, 1b, 2a, 2b of the plate thickness T1 are arranged one by one on both the upper and lower surfaces of the upright plate 3 or two in parallel butts are arranged in a vertical T shape. The joint between the upper and lower plates 1a, 1b, 2a, 2b and the standing plate 3 in the middle thereof, with no gap G at the butted portion of the upper and lower plates 1a, 1b, 2a, 2b The surface also has almost no gap, and is positioned and arranged with relatively high accuracy. In addition, B1 described in the figure is a plate | board thickness cross-sectional area seen from plate | board thickness T1 direction of upper board and lower board 1a, 1b, 2a, 2b.

  Further, in the first step 31, when two upper plates 1a, 2a and two lower plates 1b, 2b are butt-arranged in parallel on the upper and lower surfaces of the upright plate 3, there is almost no gap G in each butt portion. 2 or a small gap G range (less than 0.2 times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b even if there is a gap G, as shown in (1) of FIG. 0 ≦ G ≦ 0.2 × T1). It is more preferable to set it within a range of 0 ≦ G ≦ 0.1 × T1, which is preferably 0.1 times or less. Further, it is preferable that the upper plate 1a, 2a and the upper surface of the upper plate 3 or the lower plate 1b, 2b and the lower surface of the upright plate 3 have almost no gap or even 0.5 mm or less. In this way, by suppressing the gap G range and the gap, assembly accuracy and positioning accuracy are increased, and one of factors that may adversely affect the welding quality can be removed.

  In the next second step 32, as shown in FIG. 3 (2), a welding torch 13 (double-layered) having a double shield structure that flows out the shielding gas 9b of inert gas and the shielding gas 10b containing oxidizing gas. A non-consumable electrode type arc welding is performed using a shield gas supply means). At the same time, the flux-cored wire 4 that promotes the penetration depth is melted from the plate surfaces of the upper plates 1a and 2b to the standing plate 3 while being fed to the arc 6 welding portion, and as described above, the melting width w of the standing plate 3 Is formed larger than the plate thickness T1 of the upper plates 1a and 2b (w> T1), or the melt width w is formed to a size of w> T1, and at the same time the bead surface height C of the upper plates 1a and 2a is set from the plate surface. Formed in a convex shape 1 to 3 mm higher (1 ≦ C ≦ 3 mm), or the thickness of the upper plate 1a, 2a is cut through the weld cross section A of the penetration portion of the back surface of the upper plate 1a, 2a or the melting width w portion of the standing plate 3 Forming a weld metal part 7a having a penetration shape larger than the area B1 (A> B1) or having both the melt width w and the weld cross-sectional area A in the size of w> T1 and A> B1. Yes.

  After completion of the welding in the second step 32, the joint member is turned over. Thereafter, the process proceeds to the next third step 33. That is, in the third step 33, as shown in FIG. 3 (3), the welding torch 13 having a double shield structure (double gas) that allows the shielding gas 9 b of inert gas and the shielding gas 10 b containing oxidizing gas to flow out. The non-consumable electrode type arc welding is performed using the shielding gas supply means), and at the same time, the flux-cored wire 4 that promotes the penetration depth is fed to the arc 6 welding portion, while facing the upper plates 1a and 2a. The plate 1b, 2b is melted from the plate surface of the plate 1b, 2b (the corresponding lower plate 1b, 2b is in the upper position because the joint member is turned upside down) to the standing plate 3. In particular, as in the case of the second step 32, the melt width w of the upright plate 3 after passing through the back surface from the plate surface of the lower plate 1b, 2b is larger than the plate thickness T1 of the lower plate 1b, 2b. (W> T1) formation, or forming the melt width w to a size of w> T1, and simultaneously forming a bead surface height C in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface, or below The welding cross-sectional area A of the penetration part of the plate back surface of the plates 1b and 2b or the melting width portion of the standing plate 3 is made larger than the plate thickness cross-sectional area B1 of the lower plates 1b and 2b (A> B1), or the melting width w and A weld metal portion 8a having a penetration shape in which both of the weld cross-sectional areas A are formed in a size of w> T1 and A> B1 is obtained, and two weld metal portions 7b and 8b are provided at the top and bottom of the T-shaped joint. The upper and lower T-shaped welded joints 12 are obtained.

  With such a welding construction, as described above, the weld metal part with good quality without welding defects such as lack of melting and undercut and porosity by wire welding filling and securing of the welding cross-sectional area A (A> B1). It is possible to obtain a welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints 12 having the upper and lower portions 7a, 7b, 8a, and 8b and the upper and lower plates. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

As described above, the flux agent filled in the flux-cored wire 4 is a powder agent in which an oxide composed of at least TiO ₂ , Cr ₂ O ₃ and SiO ₂ is mixed. The amount of welding of the flux-cored wire fed to the arc 6 welded part is in the range of 1 g / min to 7 g / min, preferably in the range of 2 g / min to 5 g / min. The melting width w is larger than the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (w> T1), and the content of oxygen gas contained in the weld metal portions 7b, 8b is 100 wt. The thickness T1 of the upper and lower T-type welded joints and the upper and lower plates 1a, 1b, 2a and 2b having the weld metal portions 7b and 8b with good quality on both the upper and lower sides by being in the range of .ppm to 200wt.ppm. Equal to or less than the material strength of The above weld strength (eg, tensile strength) can be obtained.

  If the welding amount of the flux-cored wire 4 is less than 1 g / min, the flux-cored wire 4 becomes irregularly welded and smoothly dissolves in order to smoothly enter the molten pools 7a and 8a (in the molten metal). Since the amount becomes too small, the weld bead has an irregular shape, and at the same time, the melt depth is shallow so that it does not melt to the standing plate 3 or even if it melts to the standing plate 3, the melt width w is secured (w > T1) This is not preferable because it cannot be performed. On the other hand, if the welding amount of the flux-cored wire 4 is more than 7 g / min, the arc energy is consumed for melting the wire and the amount of dissolved oxygen becomes excessive, so that the penetration depth becomes shallow, This is not preferable because the content of the oxygen gas contained in the weld metal parts 7b and 8b exceeds an acceptable standard (for example, 200 wt. Ppm or less) and the toughness strength of the weld metal parts 7b and 8b is lowered. Therefore, when the content of oxygen gas contained in the weld metal portions 7b and 8b is in the range of 100 wt. Ppm to 200 wt. Ppm, the weld metal portion 7b having a weld strength and toughness similar to the base metal strength. , 8b and its upper and lower T-shaped welded joints 12 can be obtained.

  Further, as described above, the flux cored wire 4 can be fed from the front in the welding progress direction to the arc 6 welding portion, or can be fed from the rear in the welding progress direction to the arc 6 welding portion. In particular, by feeding the tip of the flux-cored wire 4 so as to contact or insert into the molten pool, for example, when outputting a wide range of welding current (eg, 100 A to 350 A) from a small current to a large current or a low speed Even in the case of a small amount of wire, the flux-cored wire 4 can smoothly enter the melt pool 7a directly under the arc 6 and can be stably melted and welded without forming large droplets. At the same time, it deeply melts up to the standing plate 3 from the plate surface of the upper plates 1a, 2a or the plate surface of the lower plates 1b, 2b, and the melting width w of the standing plate 3 is set to the upper plate and the lower plates 1a, 1b, 2a, 2b. A weld metal part having a penetration shape formed larger than the plate thickness T1 (w> T1) or formed so that the weld cross-sectional area A of the melt width w portion is larger than the plate thickness cross-sectional area B1 of the plate thickness T1 portion (A> B1). 7b and 8b can be obtained.

  Further, when a solid wire or a strand wire is used instead of the flux-promoting wire 4 that promotes the penetration, the shield gas 10b in which the concentration of the oxidizing gas is doubled than when the flux-cored wire 4 is used, or A large amount of oxygen dissociated from the oxidizing gas is dissolved in the molten pool by performing non-consumable electrode type arc welding using the shielding gas having an increased flow rate or flow rate of the shielding gas 10b containing the oxidizing gas. Therefore, it can be melted to a specific depth. At the same time, as described above, the weld metal parts 7a, 7b, 8a, and 8b with good quality are free from welding defects such as insufficient melting, undercut and porosity by securing the welding cross-sectional area A (A> B1). It is possible to obtain a welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints 12 and the upper and lower plates.

  On the other hand, when welding a T-type joint without the lower plates 1b and 2b and having only the upper plates 1a and 2a, as shown in FIG. By performing non-consumable electrode type arc welding using the wire 4, the melting width w of the upright plate 3 after passing through the back surface from the plate surface of the upper plates 1a and 2a is made larger than the upper plate thickness T1 (w> T1). Alternatively, the melt width w is formed in a size of w> T1, and the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) 1 to 3 mm higher than the plate surface, or the melt width portion of the upright plate 3 The weld cross-sectional area A is larger than the upper plate thickness cross-sectional area B1 (A> B1), or the melt width w and the weld cross-sectional area A are both formed as w> T1 and A> B1. Shaped weld metal parts 7a and 7b are provided on one side of the T-shaped joint. In this way, the weld strength (equivalent to or higher than the strength of the upper and lower T-type welded joints 12 having the weld metal portion 7b with good quality without welding defects such as insufficient melting, undercut and porosity) For example, tensile strength) can be obtained.

  Further, as shown in FIGS. 3 (2), (3) and (4), the upper and lower T-type welded joints of the present invention flow out of the shielding gas 9b containing inert gas and the shielding gas 10b containing oxidizing gas. A non-consumable electrode type arc welding using a double shield structure welding torch 13 (double shield gas supply means) to be formed, or the lower plate 1b facing the upper plate 1a, 2a or the upper plate 1a, 2a, 2b is performed separately from the surface of the plate 2b, and at the same time, the flux-cored wire 4 that promotes the penetration depth is melted separately up to the standing plate 3 while being fed to the arc 6 welding portion, and at least the upper plates 1a and 2a Each melt width w of the upright plate 3 after passing through the back surface from the plate surface or the plate surface of the lower plate 1b, 2b is larger than the plate thickness T1 of the upper plate and the lower plate 1a, 1b, 2a, 2b (w> T1). Formation or the melting width w is w> At the same time, the bead surface height C is formed in a convex shape 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or the upper and lower plates 1a, 1b, 2a, 2b Each weld cross-sectional area A of the penetration portion or the melt width portion of the upright plate 3 is formed larger than the plate thickness cross-sectional area B1 of the upper and lower plates 1a, 1b, 2a, 2b (A> B1), or the melt width w and Upper and lower T-type welding having a structure in which weld metal parts 7a, 7b, 8a, and 8b are formed on both the upper and lower sides of the T-type joint in which both of the weld cross-sectional areas A are formed in the size of w> T1 and A> B1. A joint 12 can also be provided.

  Further, each melting width w of the standing plate 3 is such that w> T1, or the welding cross-sectional area A is A> B1, or both the melting width w and the welding cross-sectional area A are w> T1. And weld metal parts 7b and 8b having a penetration shape having a size of any of A> B1 are formed on the T-shaped joint by arc welding of the non-consumable electrode method using the flux-cored wire 4 and the double shield gas supply means. One pass may be formed on both the upper and lower sides.

  With such a configuration, as described above, the upper and lower T-type welded joints 12 and the upper and lower plates having weld metal portions 7b and 8b of good quality without welding defects such as lack of melting, undercut and porosity on the upper and lower sides. A welding strength (for example, tensile strength) equal to or higher than the material strength of the plate thickness T1 of 1a, 1b, 2a, 2b can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs.

[Embodiment 4]
FIG. 4 is an explanatory view showing an embodiment of the welding method of the upper and lower T-shaped joint of the present invention, the laser welding procedure and the penetration shape related to the upper and lower T-shaped welded joint. The main difference from FIG. 1 and FIG. 3 is that, instead of arc welding, laser welding is performed by irradiating a laser beam with a focus blur using a laser torch, and at the same time a wire is fed to the laser welding portion while It was made to melt even to the standing plate. Other parts and symbols are substantially the same as those in FIGS. 1 and 3.

  That is, as shown in (2) of FIG. 4, in the focus-blurring laser welding (second step 35), the position (distance) where the focal position 19 of the laser beam 18 is shifted upward from the plate surfaces of the upper plates 1a and 2a. L), the laser torch 17 is arranged so that the laser beam 18 is irradiated with the laser beam 18 for defocusing, and at the same time, the wire 44 is fed to the laser welding portion and melted to the standing plate 3 to at least the upper plate 1a. , 2a The melting width w of the upright plate 3 after penetrating the back surface is formed to be larger than the thickness T1 of the upper plates 1a, 2a (w> T1), or the melting width w is formed to the size of w> T1 and the upper plate at the same time The bead surface height C of 1a, 2a is formed in a convex shape 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm), or the penetration portion of the back surface of the upper plates 1a, 2a or the melting width w portion of the standing plate 3 Weld cross section A is the upper plate 1a, A weld metal portion 77a having a penetration shape that is larger than the plate thickness cross-sectional area B1 of 2a (A> B1) or in which both the melt width w and the weld cross-sectional area A are w> T1 and A> B1. Like to get.

In particular, the focus position 19 of the laser beam 18 to be used is shifted upward by at least a position L (for example, a distance L> T1 larger than the plate thickness T1 of the upper plates 1a and 2a) from the upper surface of the upper plates 1a and 2a. A laser torch 17 (for example, a laser processing torch composed of a condensing lens or the like for condensing the laser beam 18 and irradiating the workpiece) so that the laser beam is defocused. It is important to irradiate the part to be welded 18. By performing laser welding using the laser beam 18 with such a defocused focus, it is possible to change from a conventional keyhole-type penetration configuration that deeply melts in the depth direction to a penetration configuration that spreads in the width direction. Due to this change in the melting form, the generation of metal vapor and spatter can be drastically reduced, and at the same time, the melting width w of the upright plate 3 is formed larger than the plate thickness T1 (w> T1) of the upper plates 1a and 2a. It is possible to obtain a weld metal portion 77a having a penetration shape in which the weld cross section A of the melt width w is larger than the plate thickness cross section B1 of the upper plates 1a and 2a (A> B1). For the laser beam 18, a commercially available CO ₂ laser, YAG laser, fiber laser, or disk laser may be used.

  When the focal position of the laser beam 18 is determined to be just hocus (distance L = 0), which is the plate surface, or when it is determined on the inner side of the T-shaped joint (distance L <0), it deeply melts in the depth direction. The conventional keyhole-type penetration form results in a deep penetration shape, and conversely, the penetration width in the welding width direction is narrowed. Therefore, the melting width w of the upright plate 3 is larger than the thickness T1 of the upper plate (w> T1) It cannot be formed. Furthermore, since metal vapor and spatter frequently occur, it is not preferable.

The wire 44 fed to the laser welded portion may be a solid wire or a strand wire that is the same type as that of the T-shaped joint member. It is also possible to use the flux-cored wire 4 that promotes melting. Ar gas or N ₂ gas may be used for the shield gas 9c flowing through the laser welding portion. As described above, in the atmosphere of the shielding gas 9c, by performing laser welding by irradiating the laser beam 18 with the focus blurring and feeding and welding the wire 44 to the laser welded portion, insufficient melting, undercut, porosity, etc. It is possible to obtain the weld metal parts 77b and 88b with good quality without any weld defects and the upper and lower T-type welded joints 14 provided with the weld metal parts 77b and 88b on the upper and lower sides.

  In the first step 31, as shown in FIG. 4 (1), the upper plate and the lower plate along the horizontal direction on the upper and lower surfaces (both surfaces of the vertical plate) along the vertical direction with respect to the floor surface. A T-shaped joint is formed by arranging 1a, 1b, 2a, 2b one by one, or two upper and lower plates 1a, 1b, 2a, 2b in parallel butting in parallel. As described above, the T-shaped joint to be welded is a welded article incorporated in nuclear equipment or thermal equipment. The plate thickness T1 of the upper and lower plates 1a, 1b, 2a, and 2b is 2 <T1 ≦ 6 mm. Preferably, it is further better to keep it in the range of 2 <T1 ≦ 5 mm. The plate thickness T2 range of the upright plate 3 is not less than 2 times and not more than 5 times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (2 × T1 ≦ T2 ≦ 5 × T1), The upper plate and the lower plate 1a, 1b, 2a, 2b of the plate thickness T1 are arranged one by one on both the upper and lower surfaces of the upright plate 3 or two in parallel butts are arranged in a vertical T shape. The joint between the upper and lower plates 1a, 1b, 2a, 2b and the standing plate 3 in the middle thereof, with no gap G at the butted portion of the upper and lower plates 1a, 1b, 2a, 2b The surface also has almost no gap, and is positioned and arranged with relatively high accuracy.

  As described above, if the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b is less than 2 mm, welding deformation due to excessive melting tends to increase. On the contrary, if the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b is larger than 6 mm, it becomes difficult to form the melt width w of the upright plate 3 to a sufficient size. Forcibly melting and bonding requires a high-power laser transmission device and is not preferable because welding deformation due to excessive melting of the upper and lower plates 1a, 1b, 2a, and 2b tends to increase. On the other hand, if the plate thickness T2 of the standing plate 3 is thinner than twice the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b, for example, the upper and lower plates 1a, 1b, 2a, When the position of the welding line 2b and the both sides of the standing plate 3 is misaligned, the one end surface portion of the standing plate 3 is likely to melt and sag, or the penetration is likely to be uneven or distorted. On the contrary, if the plate thickness T2 of the standing plate 3 is thicker than five times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b, the melting width w of the standing plate 3 with respect to the plate thickness T2 of the standing plate 3 and This is not preferable because the ratio of the weld cross-sectional area A is reduced, and the balance of the plate thickness T1 with the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b is deteriorated and the weight of the material itself is increased.

  In addition, as described above, B1 described in FIG. 4 is the plate thickness cross-sectional area of the upper and lower plates 1a, 1b, 2a, 2b as viewed from the plate thickness T1 direction. The weld cross-sectional area A of the melt width w portion of the plate 3 is obtained by the product (A = w × L) of the melt width w of the upright plate 3 and the weld line length L. Similarly, the plate thickness cross-sectional area B1 in the plate thickness T1 direction is obtained by the product of the plate thickness T1 of the upper plates 1 and 2 and the weld line length L (B1 = T1 × L), and the melting width w is defined as If formed so as to satisfy w> T1, the weld cross-sectional area A at that time is formed larger than the plate thickness cross-sectional area B1 (A> B1).

  In the next second step 35, as shown in FIG. 4 (2), while performing laser welding by irradiating the laser beam 18 for defocusing, the upper plate 1a, 2a is melted from the plate surface to the standing plate 3, and at least the melting width w of the standing plate 3 is formed larger than the plate thickness T1 of the upper plates 1a, 2a (w> T1), or the melting width w portion of the standing plate 3 The welding cross-sectional area A is formed larger than the plate thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1), or both the melt width w and the welding cross-sectional area A are set to w> T1 and A> B1 The formed weld metal portion 77a having a penetration shape is obtained. As a result, the weld strength equal to or higher than the material strength of the upper and lower T-type welded joints 14 and the upper plates 1a and 2a provided with weld metal portions 77b and 77b of good quality without welding defects such as lack of melting, undercut and porosity. Strength can be obtained.

  After completion of the welding in the second step 35, the joint member is turned over. Thereafter, the process proceeds to the next third step 36. That is, in the third step 36, as shown in FIG. 4 (3), while performing laser welding by irradiating the laser beam 18 for defocusing, the upper plate 1 a , 2a, the lower plate 1b, 2b is melted from the plate surface of the lower plate 1b, 2b (the corresponding lower plate 1b, 2b is in the upper position because the joint member is turned upside down) to the standing plate 3. In particular, as in the case of the second step 35, at least the melt width w of the standing plate 3 is formed larger than the plate thickness T1 (w> T1) of the lower plates 1b and 2b by the melt bonding, or the melt width w is formed in the size of w> T1, and at the same time, the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) higher by 1 to 3 mm than the plate surface, or the through portion of the back surface of the lower plates 1b and 2b or The welding cross-sectional area A of the melting width portion of the upright plate 3 is formed larger than the plate thickness cross-sectional area B1 of the lower plates 1b and 2b (A> B1), or both the melting width w and the welding cross-sectional area A are w> T1. A weld metal portion 88a having a penetration shape formed in a size of A> B1 is obtained, and an upper and lower T-type weld joint 14 having two weld metal portions 77b and 88b provided above and below the T-type joint is obtained. ing.

  With such a welding construction, as described above, the weld metal part with good quality without welding defects such as lack of melting and undercut and porosity by wire welding filling and securing of the welding cross-sectional area A (A> B1). It is possible to obtain a welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints 14 having the upper and lower portions 77b, 77b, 88a, and 88b. In addition, the number of work steps can be greatly reduced as compared with conventional multi-pass welding or flux coating type welding. Furthermore, since the amount of heat input of laser welding is smaller than that of arc welding and the amount of deformation is also reduced, the work for removing strain can be reduced and the productivity can be further increased.

  Further, as described above, the melting width w of the upright plate 3 is formed so that w> T1 and at the same time the bead surface height C is formed to be 1 to 3 mm higher than the plate surface (1 ≦ C ≦ 3 mm) As a result, a sound weld metal part having a predetermined shape can be obtained, and a good weld bead having a convex shape without a dent or undercut on the weld surface of the T-shaped joint can be obtained. If the bead surface height C is less than 1 mm, an undercut is likely to occur at the bead boundary. On the other hand, if the bead surface height C is larger than 3 mm, the penetration depth becomes shallow, the bead appearance is deteriorated, and an excessive protruding portion is not preferable.

  Further, when the T-shaped joint is welded by changing from the downward posture to the horizontal posture or the vertical posture, the joint members 1a, 1b, 2a, 2b, 3 are assembled and arranged in the horizontal posture or the vertical posture (the joint member 1a). , 1b, 2a, 2b, 3 rotated 90 degrees counterclockwise) and then performing laser welding using the defocused laser beam 18 (for example, the upper plate 1a, 2a side) Welding from the surface to the standing plate 3 in a horizontal posture or a vertical posture, and then welding from the other (for example, the lower plate 1b, 2b side) plate surface to the vertical plate 3 in a horizontal posture or a vertical posture. Or by performing two sets of laser welding using the defocused laser beam 18, the vertical plate 3 in the horizontal position or the vertical position with the joint portions on the left and right sides at positions far apart in time and space. Until each welded separately, less Also, the weld metal portions 77a, 77b, 78a, 78b having a penetration shape in which the melt width w of the upright plate 3 has a size of w> T1 or the weld cross-sectional area A of the melt width w portion of A> B1 is T. By providing on both the left and right sides of the mold joint, the welding operation time can be greatly shortened, and weld metal portions 77b and 78b having a sound penetration shape and the upper and lower T-shaped weld joints 14 can be obtained.

  Further, as shown in FIGS. 4 (2), (3), and (4), in the upper and lower T-type welded joints of the present invention, laser welding using the laser beam 18 of the above-described defocusing is performed on the upper plates 1a and 2a. It is performed separately from the plate surface or the plate surfaces of the lower plates 1b and 2b facing the upper plates 1a and 2a, and at the same time, the wires 44 are fed to the laser welded portion and melted separately up to the standing plate 3, respectively. Each melt width w of the upright plate 3 after back surface penetration from the plate surface of the upper and lower plates 1a, 2a, 1b, 2b is formed larger than the plate thickness T1 (w> T1), or the melt width w is set to w > T1 is formed in a convex shape (1 ≦ C ≦ 3 mm) with a bead surface height C 1 to 3 mm higher than the plate surface at the same time, or the back side of the upper and lower plates 1a, 1b, 2a and 2b Each welding cross-sectional area A of the penetration part of the above or the melting width w part of the upright plate 3 The upper and lower plates 1a, 1b, 2a and 2b are formed larger than the plate thickness cross-sectional area B1 (A> B1), or both the melt width w and the weld cross-sectional area A are larger than w> T1 and A> B1. The weld metal portions 77a, 77b, 88a, 88b having a penetration shape formed on the upper and lower sides can be formed into the upper and lower T-type weld joint 14 having a structure provided on both upper and lower sides of the T-type joint.

  Further, each melting width w of the standing plate 3 is such that w> T1, or the welding cross-sectional area A is A> B1, or both the melting width w and the welding cross-sectional area A are w> T1. And weld metal parts 77b and 88b having a penetration shape having a size of either A> B1 are formed on each of the upper and lower sides of the T-shaped joint by laser welding using the laser beam with the defocusing. You can also.

  With such a configuration, as described above, the upper and lower T-type welded joints 14 and the upper and lower plates having the weld metal portions 77b and 88b of good quality without welding defects such as insufficient melting and undercut and porosity on the upper and lower sides. A welding strength (for example, tensile strength) equal to or higher than the material strength of the plate thickness T1 of 1a, 1b, 2a, 2b can be obtained. In addition, the number of work steps can be greatly reduced as compared with conventional multi-pass welding or flux coating type welding. Furthermore, since the amount of heat input of laser welding is smaller than that of arc welding and the amount of deformation is also reduced, the work for removing strain can be reduced and the productivity can be further increased.

[Embodiment 5]
FIG. 5 is an explanatory view showing another embodiment of the welding method for the upper and lower T-shaped joints of the present invention, the laser welding procedure and the penetration shape relating to the upper and lower T-shaped welded joints. The main difference from FIG. 4 is that when two upper plates 1a, 2a and two lower plates 2b, 2b are butt-arranged in parallel on the upper and lower surfaces of the upright plate 3, the butt portion between the upper plates 1a, 2a or the lower plate This is an example of a T-shaped joint in which there is no gap G at the abutting portion between the plates 1b and 2b, and other parts and symbols are substantially the same as those in FIG.

  As described above, it is unexpectedly difficult to assemble a T-shaped joint having a long weld line without the gap G, and the gap G is formed in the butt portion between the upper plates 1a and 2a or the butt portion between the lower plates 1b and 2b. In addition, there is a slight gap on the upper surface of the upper plates 1a, 2a and the upright plate 3 or on the joint contact surface between the lower plates 1b, 2b and the lower surface of the upright plate 3. May or may not be. In particular, when the gap G is excessively large as a whole, or when the gap G changes greatly, which sometimes exceeds the allowable value, the welding quality is adversely affected (for example, uneven penetration, uneven bead shape, Cut). In order to avoid this, in this embodiment, the allowable gap G range is limited as follows.

  That is, as shown in FIG. 5 (1), in the first first step 31, when two upper plates 1a, 2a and two lower plates 1b, 2b are butt-arranged in parallel on the upper and lower surfaces of the upright plate 3, respectively. Even if there is almost no gap G at each butting portion, a small gap G range not more than 0.2 times the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b (0 ≦ G ≦ 0) .2 × T1). It is more preferable to set it within a range of 0 ≦ G ≦ 0.1 × T1, which is preferably 0.1 times or less. Further, it is preferable that the upper plate 1a, 2a and the upper surface of the upper plate 3 or the lower plate 1b, 2b and the lower surface of the upright plate 3 have almost no gap or even 0.5 mm or less. In this way, by suppressing the gap G range and the gap, assembly accuracy and positioning accuracy are increased, and one of factors that may adversely affect the welding quality can be removed. In addition, as described above, the T-shaped joint to be welded is a welded object incorporated in, for example, nuclear equipment or thermal equipment. Particularly, it is made of stainless steel or general carbon steel excellent in corrosion resistance, and the plate thickness T1 range of the upper plate and lower plate 1a, 1b, 2a, 2b is 2 <T1 ≦ 6 mm, and the plate thickness of the upright plate 3 The range of T2 is not less than 2 times and not more than 5 times (2 × T1 ≦ T2 ≦ 5 × T1) the plate thickness T1 of the upper and lower plates 1a, 1b, 2a, 2b. An upper plate and a lower plate 1a, 1b, 2a, 2b having a thickness T1 are arranged in parallel in a horizontal direction so that a joint is formed in an upper and lower T shape.

  In the next second step 35, as shown in FIG. 5 (2), while performing laser welding by irradiation of the laser beam 18 for defocusing, the upper plate 1a, 2a is melted from the plate surface to the standing plate 3, and at least the melting width w of the standing plate 3 is formed larger than the plate thickness T1 of the upper plates 1a and 2a (w> T1), or the melting width w is larger than w> T1. At the same time, the bead surface height C of the upper plates 1a, 2a is formed in a convex shape (1 ≦ C ≦ 3 mm) which is 1 to 3 mm higher than the upper plate surface, or the welding cut of the melting width w portion of the standing plate 3 The area A is formed larger than the plate thickness cross-sectional area B1 of the upper plates 1a and 2a (A> B1), or both the melt width w and the weld cross-sectional area A are formed in the size of w> T1 and A> B1. A weld metal portion 77a having a penetration shape is obtained, and further, a weld metal The upper and lower T-type welded joints 14 having the genus parts 77a and 77b on one side of the T-type joint are obtained.

  After completion of the welding in the second step 35, the joint member is turned over. Thereafter, the process proceeds to the next third step 36. That is, in the third step 36, as shown in FIG. 5 (3), while performing laser welding by irradiating the laser beam 18 for defocusing, the wire 44 is fed to the laser welding portion and at the same time, the upper plate 1a. , 2a facing lower plate 1b, 2b (the corresponding lower plate 1b, 2b is at the upper position because the joint member is turned upside down) is melted from the plate surface to the standing plate 3 side. In particular, as in the case of the second step 35, at least the melt width w of the standing plate 3 is formed larger than the plate thickness T1 (w> T1) of the lower plates 1b and 2b by the melt bonding, or the melt width w is formed in the size of w> T1, and at the same time, the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) higher by 1 to 3 mm than the plate surface, or the through portion of the back surface of the lower plates 1b and 2b or The welding cross-sectional area A of the melting width portion of the upright plate 3 is formed larger than the plate thickness cross-sectional area B1 of the lower plates 1b and 2b (A> B1), or both the melting width w and the welding cross-sectional area A are w> T1. A weld metal portion 88a having a penetration shape formed in a size of A> B1 is obtained, and an upper and lower T-type weld joint 14 having two weld metal portions 77b and 88b provided above and below the T-type joint is obtained. ing.

  With such a welding construction, as described above, the weld metal part with good quality without welding defects such as lack of melting and undercut and porosity by wire welding filling and securing of the welding cross-sectional area A (A> B1). Welding strength (for example, tensile strength) equal to or higher than the material strength of the upper and lower T-type welded joints 14 having the upper and lower portions 77a, 77b, 88a, and 88b and the upper and lower plates can be obtained. In addition, the number of work steps can be greatly reduced as compared with conventional multi-pass welding or flux coating type welding. Furthermore, since the amount of heat input of laser welding is smaller than that of arc welding and the amount of deformation is also reduced, the work for removing strain can be reduced and the productivity can be further increased.

  In addition, it is most preferable to achieve the upper and lower T-type welded joints 14 having the weld metal portions 77b and 88b having a predetermined shape on both upper and lower sides by welding one pass at a time. When surplus or undercut occurs, a second pass of welding should be added. The melting width w and the welding cross-sectional area A of the upright plate 3 have already been formed to a predetermined size (w> T1, A> B1) by the first pass welding. Therefore, when welding in the second pass, the welding of the first pass is performed so that the surface of each weld bead of the upper plate 1a, 2a or the lower plate 1b, 2b is in a predetermined range (1 ≦ C ≦ 3 mm). Review the work conditions, determine the welding conditions for the second pass, and re-execute laser welding using the laser beam with the focus blur from the bead surface of the previous layer welding, thereby eliminating the above-mentioned lack of surplus and undercut. Thus, it is possible to improve the weld metal part 7b having a weld bead with a surplus height and a penetration shape.

  Further, in the case of a T-type joint without the lower plates 1b and 2b, the laser welding in the third step 36 is not necessary, and the upper plates 1b and 2b are welded to the upright plate 3 by performing the laser welding in the second step 35. do it. That is, as shown in (2) of FIG. 4 and (2) of FIG. 5, by performing laser welding using the laser beam 18 for defocusing, the surface of the upper plates 1a and 2a after the back surface has been penetrated. Form the melt width w of the upright plate 3 larger than the plate thickness T1 of the upper plates 1a and 2a (w> T1), or form the melt width w so as to satisfy the size of w> T1, and simultaneously set the bead surface height C to the plate. Forming a convex shape 1 to 3 mm higher than the surface (1 ≦ C ≦ 3 mm), or forming a welding cross-sectional area A of the melting width w portion on the standing plate 3 side larger than the upper plate thickness cross-sectional area B1 (A> B1), Or it is good to provide the weld metal part 7a, 7b of the penetration shape which formed both the said melt width w and the said weld cross-sectional area A in the magnitude | size of w> T1 and A> B1 in the one side of a T-type coupling. Accordingly, as described above, the weld strength (equal or better than the strength of the upper and lower T-type welded joints 14 having the weld metal portion 77b having good quality without welding defects such as insufficient melting, undercut and porosity) For example, tensile strength) can be obtained.

  Further, as shown in FIGS. 5 (2), (3) and (4), in the upper and lower T-type welded joints of the present invention, laser welding using the laser beam 18 of the above-mentioned defocusing is performed on the upper plates 1a and 2a. It is performed separately from the plate surface or the plate surfaces of the lower plates 1b and 2b facing the upper plates 1a and 2a, and at the same time, the wires 44 are fed to the laser welded portion and melted separately up to the standing plate 3, respectively. Each melt width w of the upright plate 3 after back surface penetration from the plate surface of the upper and lower plates 1a, 2a, 1b, 2b is formed larger than the plate thickness T1 (w> T1), or the melt width w is set to w > T1 is formed in a convex shape (1 ≦ C ≦ 3 mm) with a bead surface height C 1 to 3 mm higher than the plate surface at the same time, or the back side of the upper and lower plates 1a, 1b, 2a and 2b Each welding cross-sectional area A of the penetration part of the above or the melting width w part of the upright plate 3 The upper and lower plates 1a, 1b, 2a and 2b are formed larger than the plate thickness cross-sectional area B1 (A> B1), or both the melt width w and the weld cross-sectional area A are larger than w> T1 and A> B1. The weld metal portions 77a, 77b, 88a, 88b having a penetration shape formed on the upper and lower sides can be formed into the upper and lower T-type weld joint 14 having a structure provided on both upper and lower sides of the T-type joint.

  With such a configuration, as described above, the upper and lower T-type welded joints 14 and the upper and lower plates having the weld metal portions 77b and 88b of good quality without welding defects such as insufficient melting and undercut and porosity on the upper and lower sides. A welding strength (for example, tensile strength) equal to or higher than the material strength of the plate thickness T1 of 1a, 1b, 2a, 2b can be obtained. In addition, the number of work steps can be greatly reduced as compared with conventional multi-pass welding or flux coating type welding. Furthermore, since the amount of heat input of laser welding is smaller than that of arc welding and the amount of deformation is also reduced, the work for removing strain can be reduced and the productivity can be further increased.

[Embodiment 6]
FIG. 6 is an example showing the relationship between the welding current I for each plate thickness when the welding method shown in FIG. 1 is applied, the melting width w and the penetration depth h of the upright plate 3. In the upper side in FIG. 6, representative cross-sectional photographs according to the thickness of the upper plate side welded by changing the welding current are disclosed. In the description in the frame in FIG. 6, the penetration depth h is simply described as “melting depth h”. Three types (T1 = 3, 4, 6) of the upper plate 1 having an upper plate thickness T1 of 3, 4 and 6 mm are prepared, and the plate thickness T2 of the upright plate 3 is 12 mm and constant (T2 = 12). In either case, a stainless steel material (SUS304L) was used. Also, the welding speed (the length of the weld bead per minute) is constant (65 mm / min), the feeding amount of the flux-cored wire 4 is constant (2 g / min), and the welding current I is varied according to the plate thickness of the upper plate. Welded with varying

  As is apparent from FIG. 6, the melting width w and the penetration depth h of the upright plate 3 increase with the increase of the welding current I, and in the formation region where the penetration depth h of the upright plate 3 is 1 mm or more, the melting occurs. Each of the widths w was formed to have a size equal to or greater than the plate thickness T1 of the upper plate. For example, the welding current I formed when the melting width w of the upright plate 3 is equal to or greater than the upper plate thickness T1 is about 155 A or more when the upper plate thickness is T1 = 3 mm, about 195 A or more when T1 = 4 mm, T1 In the case of 6 mm, it was about 275 A. Moreover, the cross-sectional photograph according to the plate thickness shown in FIG. 6 shows the penetration shape of the portion where the penetration depth h of the upright plate 3 is about 1.2 to 1.7 mm, and the melting width w is the upper side in any cross section. It is the result of having formed in the magnitude | size exceeding this board thickness T1.

  As described above, in this embodiment, welding conditions such as an appropriate welding current corresponding to various plate thicknesses are set to perform non-consumable electrode type arc welding, and at the same time, the flux-cored wire 4 is sent to the arc 6 welding portion. While being fed, the upper plate 1a, 2a is melted from the plate surface to the standing plate 3 side, so that a melting width w equal to or larger than the upper plate thickness T1 is formed in the standing plate 3, and the upper plates 1a, 2a and the standing plate 3 It was possible to secure a weld cross-sectional area A equal to or greater than the plate thickness cross-sectional area of the weld metal portion 7b and the upper plate 1 that were reliably melt-bonded to each other. It was also confirmed that an upper and lower T-shaped welded joint including the weld metal portion 7b having such a size can be manufactured. Here, the penetration shape of one of the upper and lower T-shaped welded joints and the weld cross-sectional photograph thereof are described. However, as shown in FIGS. 1 (2) to (4), both-side welding of the T-shaped joint is performed. Thus, the upper and lower T-type welded joints 12 having the weld metal portions 7b and 8b having the above-described penetration shape and size can be obtained.

[Embodiment 7]
FIG. 7 is an example showing the relationship between the welding current I, the heat input Q, and the penetration depth H from the upper plate surface when the welding method shown in FIG. 1 is applied. In the description in the frame in FIG. 7, the penetration depth H from the upper plate surface is simply described as “penetration depth H”, and the penetration depth h of the standing plate is described as “melting depth h”. Three kinds of upper plates 1a (T1 = 3, 4, 6 mm) having an upper plate thickness T1 of 3, 4, 6 mm are prepared, and the plate thickness T2 of the upright plate 3 is set to 12 mm and constant (T2 = 12). In either case, a stainless steel material (SUS304L) was used. Further, the welding speed (the length of the weld bead per minute) is constant (65 mm / min), the feeding amount of the flux-cored wire is constant (2 g / min), and the welding current I is varied according to the thickness of the upper plate 1a. Welded with varying The welding heat input Q (kJ / cm) was calculated from the relationship between the welding current I (A), the arc voltage Va (V), and the welding speed V (mm / min). The penetration depth H from the upper plate surface is a value obtained by adding the upper plate thickness T1 and the fusion depth h of the lower standing plate 3 (H = T1 + h).

  As is apparent from FIG. 7, the penetration depth H from the upper plate surface has a large welding current I for any plate thickness (T1 = 3,4,6 mm) when the welding speed is constant (65 mm / min). It increases almost proportionally. Similarly, the heat input Q of welding increases in proportion to the magnitude of the welding current I. The melting width w of the upright plate 3 is the value shown in FIG. Therefore, appropriate welding conditions such as welding current I and heat input Q corresponding to various plate thicknesses are set so that the melting width w of the standing plate 3 is larger than the plate thickness T1 of the upper plate 1a (w> T1). At the same time as performing the arc welding, it is preferable to melt the flux-cored wire 4 that promotes the penetration depth from the upper plate surface to the upright plate 3 while feeding it to the arc 6 welding portion. By welding in this way, a weld cross section A having a larger shape (A> B1) than the plate thickness cross section B1 of the weld metal portion 7b and the upper plate 1a which reliably melt-bonded the upper plate 1a and the upright plate 3 is obtained. I was able to get it. Here, the relationship between the welding current I, the heat input Q, and the penetration depth H from the plate surface in one of the upper and lower T-type welded joints is described, but as shown in (2) to (4) of FIG. In addition, by performing both-side welding of the T-shaped joint, it is possible to obtain the upper and lower T-shaped welded joints 12 having the weld metal portions 7b and 8b having the above-described penetration shape and size on both the upper and lower sides, and the upper plate. And the welding cross-sectional area A of the shape larger than the plate | board thickness cross-sectional area B1 of the lower board 1a, 1b, 2a, 2b (A> B1) can be obtained.

[Embodiment 8]
FIG. 8 is an example showing the relationship between the welding amount of the flux-cored wire, the penetration depth, and the O gas content in the molten metal part when the welding method shown in FIG. 1 is applied. Using stainless steel (material SUS304L, plate thickness 9.7 mm), welding speed is constant (65 mm / min), welding current is changed within the range of 200 to 260 A, and penetration of flux-cored wire 4 that promotes penetration Welding was performed while changing the feeding amount (0 to 8.6 g / min). It is the result of collecting a predetermined amount of weld metal part (metal part) and analyzing and measuring the O gas content in the metal part by the melting infrared absorption method. In FIG. 8, the welding amount range of the flux-cored wire 4 and the minimum value of the O gas content in a region where a penetration depth of 1/2 or more of the used plate thickness is secured are shown.

  As is apparent from FIG. 8, when the welding amount of the flux-cored wire is 0 g / min (no wire), the O gas content in the molten metal part is as low as 17 wt.ppm, which is about half the value of the base metal part. In addition, the penetration depth is shallow at 3 mm or less, has not reached a specific penetration (for example, a penetration depth capable of penetrating and melting the upper plate T1 having a thickness of 4 to 5 mm), and is insufficiently melted. Has reached. When the welding amount of the flux-cored wire is in the range of 0.8 to 6.8 g / min, the penetration depth is as deep as 5.6 to 7 mm, and reaches a specific penetration depth. The O gas content at this time varies slightly, but is in the range of 100 to 250 wt. Ppm. When the welding amount of the flux-cored wire is larger than the above range (for example, 8.6 g / min), the penetration depth is reduced to 3.4 mm and does not reach the specific depth, resulting in insufficient melting. . In the welding of the T-shaped joint, it is necessary to melt from the plate surface of the upper plates 1a and 2a to the standing plate 3, and the melting width w of the standing plate 3 is larger than the thickness T1 of the upper plates 1a and 2a (w> T1). ) It is most important to form. Therefore, as shown in FIG. 8, the welding amount of the flux-cored wire in which the melt width w of the upright plate 3 (joint surface portion between the upper plate and the upright plate) is such that w> T1 is 0.8-6. It was within the range of 0.8 g / min, and was rounded off to the appropriate range from 1 g / min to 7 g / min. Further, the O gas content contained in the molten metal part having the penetration depth is in the range of 100 to 250 wt.ppm, but if it exceeds 200 wt.ppm, the toughness strength of the molten metal part is preferably reduced. Since it was not, it was rounded down and limited to the range of 100 wt.ppm to 200 wt.ppm. In addition, about the adjustment of the welding width w of the standing board 3, in addition to the welding amount of the said flux cored wire, it can adjust by the magnitude | size of welding heat input conditions, such as welding current I and a welding speed, The board thickness of a joint member It is preferable to perform a confirmation test in advance and make adjustments so as to ensure a predetermined range of melt width w or weld cross section A according to the application.

  As shown in FIGS. 1 to 5, arc welding is performed with a welding current corresponding to the plate thickness T1 range (2 <T1 ≦ 6 mm) of the upper and lower plates 1a, 2a, 1b and 2b of the T-shaped joint, At the same time as performing laser welding by defocusing laser beam irradiation, the welding amount of the flux-cored wire fed to the arc welding part or the laser welding part is in the range of 1 g / min to 7 g / min, preferably 2 g. The melting width w of the upright plate 3 is larger than the plate thickness T1 of the upper and lower plates 1a, 2a, 1b, 2b (w> T1). In addition, the weld metal parts 7b, 77b, 8b, 88b having good quality are provided on both the upper and lower sides when the content of oxygen gas contained in the weld metal part is in the range of 100 wt.ppm to 200 wt.ppm. Upper and lower T-type welded joint Fine top and material strength equal to or higher than the welding strength of the lower plate (e.g. tensile strength) can be obtained.

[Embodiment 9]
FIG. 9 is a perspective view of an embodiment showing an outline of a welded structure having a plurality of T-shaped joints and weld lines. In the lower part of FIG. 9, the cross section A of the welded portion of the T-shaped joint and the cross section B of the welded portion of the corner joint are shown. A plurality of upper plates 1a, 2a and lower plates 1b, 2b extending in the horizontal direction from both the upper and lower sides are arranged on the upper and lower surfaces of the plurality of standing plates 3 along the vertical direction with respect to the floor surface, respectively, so as to form a vertical T shape. It is the welded structure 28 of the comprised T-shaped joint. The welded structure 28 is incorporated in, for example, nuclear equipment or thermal equipment, and is deployed in an environmental state in which most of the welded portions of the upper and lower T-type welded joints come into contact with a high-temperature steam medium or corrosive medium. It will be. A plurality of upper plates 1a, 1b and lower plates 2a, 2b arranged on the upper and lower surfaces of the plurality of standing plates 3 are many on the plate surfaces of other portions excluding the portions of the welding lines 15 and 16 and the vicinity thereof. Are the perforated plates in which the holes are formed in advance, and the thick black line portions are the weld lines 15 and 16. The material of the welded structure 28 is stainless steel having excellent corrosion resistance, and has a structure in which a high-temperature steam body or corrosive fluid mainly passes through the holes. A welding line 15 shown in FIG. 9 is a welded portion of a T-shaped joint, and a welded line 16 at both left and right end portions is a welded portion of a corner joint. As described above, the plate thickness T1 range of the upper plates 1a and 2a and the lower plates 1b and 2b respectively disposed on the upper and lower surfaces of the upright plate 3 is 2 <T1 ≦ 6 mm.

  The welded portion of the T-shaped joint (weld line 15, cross section A) is welded to the vertical plate 3 by applying the welding method shown in FIGS. (Welding line 16, cross section B) is square-welded by applying the welding method so that the melting width w of the upright plate 3 is greater than w> T1. That is, by performing the non-consumable electrode type arc welding using the fusion-promoting flux-cored wire 4 or the laser welding using the laser beam of the focal blur, each melting width w of the upright plate 3 satisfies w> T1. The weld metal parts 7b and 8b having a penetration shape formed such that the weld cross-sectional area A of the melt width w portion has a size of A> B1 are provided on both the upper and lower sides of the T-type joint or the upper and lower sides of the square joint, respectively. This is a welded structure 28 having the structure provided.

  With such a construction of welding construction, as described above, upper and lower T-shaped welding provided with weld metal parts 7b, 77b, 8b and 88b of good quality without welding defects such as insufficient melting, undercut and porosity. Since the joints 12 and 14 or the rectangular welded joint and the welded structure 28 using the same are obtained, and the weld cross-sectional area A of the melting width w portion of the upright plate 3 is secured (A> B1), A weld strength (for example, tensile strength) equal to or greater than the plate thickness material strength of the plate and the lower plate can be obtained. In addition, since the amount of deformation is significantly reduced as compared with the conventional multi-pass welding, it is possible to reduce the work for removing distortion, and it is possible to improve productivity and reduce costs. Further, the welded structure 28 is incorporated in nuclear equipment or thermal power equipment, and the weld metal portions 7b, 77b, 8b, 88b, 15 of the upper and lower T-type welded joints 12, 14 or the upper and lower T-type welded joints 12, 14 and Since the welded structure 28 including the welded portion 16 and the cross-section B of the side-by-side square welded joints is deployed in an environmental state in contact with the high-temperature steam medium or corrosive medium, the steam medium environment is activated by the operation of nuclear equipment or thermal equipment. Even if it is applied for a long time under a corrosive environment, corrosion resistance and weld strength are high, so that an event such as corrosion cracking can be prevented, which contributes to a longer life.

  As described above, according to the welding method of the upper and lower T-shaped joints of the present invention, the upper and lower T-shaped welded joints 12 and 14 and the welded structure 28 using the same, welding defects such as insufficient melting, undercut and porosity are provided. There are obtained upper and lower T-type welded joints 12 and 14 having weld metal portions 7b, 77b, 8b and 88b with good quality, and a welded structure 28 using the same. Since the cross-sectional area A is ensured (A> B1), a welding strength (for example, tensile strength) equal to or higher than the material strength of the upper plate and the lower plate can be obtained. In addition, the number of work steps can be significantly reduced compared to conventional multi-pass welding and flux application welding, and at the same time, the amount of deformation is greatly reduced compared to the large deformation that has occurred in multi-pass welding, so the work to remove distortion It is possible to improve productivity and reduce costs. Furthermore, even if it is applied for a long period of time in a steam medium environment or a corrosive environment due to the operation of nuclear equipment or thermal equipment, the corrosion resistance and welding strength are high, so it is possible to prevent corrosion cracking and other events and contribute to a longer life. it can.

[Comparative Example]
FIG. 10 is a cross-sectional view of a comparative example showing a multi-pass welding shape of a grooved T-shaped joint by a conventional TIG welding method. Moreover, FIG. 11 is sectional drawing of the other comparative example which shows the multipass welding shape of the other T type joint with a gap by the conventional TIG welding method. Furthermore, FIG. 12 is a cross-sectional view of still another comparative example showing a multi-pass welded shape of another G-type joint with a gap by a conventional TIG welding method.

  That is, in the conventional TIG welding method, since the penetration is shallow, as shown in (1) of FIG. 10, in order to make the upper plate 1 and the standing plate 3 easy to melt, groove grooves 20 are formed on the surface portion of the upper plate 1. Formed and thinned. Then, as shown in FIG. 10 (2), first, the thin-walled portion of the groove 20 is welded and melted up to the standing plate 3 to form the first layer welded portion 22. Thereafter, multi-pass welding is performed in which a plurality of laminated welds 23 are sequentially laminated up to the upper part of the upper plate 1. As another method according to the comparative example, as shown in FIGS. 11 (1) and (2), a large gap 21 (gap G) is provided at the joint portion where the two upper plates 1 and 2 are arranged in parallel. Then, after welding the bottom portion of the joint gap 21 and the space portion on the upright plate 3 side to melt up to the upright plate 3 to form the first layer welded portion 22, a plurality of laminated welded portions 23 are sequentially laminated up to the upper portion of the groove. Performs multi-pass welding. Further, as another method related to the comparative example, as shown in FIGS. 12 (1) and (2), a large joint gap 21 is provided at a joint portion in which two upper plates 1 and 2 are arranged in parallel. After the plate 3 and the left and right upper plates 1 are each fillet welded 24, welding 25 is performed to build up the central portion of the remaining joint.

  For this reason, the conventional TIG welding method shown in FIGS. 10, 11 and 12 has a problem that multi-pass welding with increased man-hours is required, and the welding deformation tends to increase.

  FIG. 13 is a cross-sectional view of a comparative example showing a penetration shape of a T-shaped joint by a conventional laser welding method. That is, in the conventional laser welding method, keyhole type deep penetration and narrow width welding are performed. Therefore, as shown in FIG. Since the melting width w of the plate 3 is narrow, the welding cross-sectional area correlated with the welding strength is small. Also, metal vapor and spatter are likely to occur frequently during laser welding. In order to increase the cumulative weld cross-sectional area, for example, a plurality of laser welds 26 are formed by irradiating a plurality of laser beams to a plurality of locations, and a plurality of narrow melting widths w are added to widen each.

DESCRIPTION OF SYMBOLS 1a, 2a Top plate 1b of a T type joint, 2b Bottom plate of a T type joint 3 Standing plate 4 of a T type joint 4 Flux-cored wire 5 Non-consumable electrode 6 Arc 7a, 77a, 8a, 88a Molten metal (molten pool)
7b, 77b, 8b, 88b Weld metal portion 9a Inner nozzle 9b Inert gas 9c Shield gas 10a Outer nozzle 10b Mixed gas containing oxidizing gas 11 Welding torch 12, 14 Upper and lower T-type welded joint 13 after welding of double shield structure Welding torch 15 T-joint weld line (welded part)
16 Welding line of square joint (welded part)
17 laser torch 18 laser beam 19 focal position 20 groove groove 21 joint gap 22 first layer welded portion 23 laminated welded portion 24, 25 fillet welded portion 26 laser welded portion 28 welded structure 44 wire T1 upper and lower plate thickness T2 vertical plate Thickness w Standing plate melt width C Bead surface height h Standing plate melting depth A Welding cross section w1 Welding sectional area B1 Thickness sectional area L of upper and lower plates Defocus height

Claims (12)

It consists of a stainless steel plate with one or two upper and lower plates placed on the top and bottom surfaces of the standing plate. While feeding the wires from the top and bottom surfaces to the standing plate side In the welding method of the upper and lower T-shaped joints for performing laser welding by non-consumable electrode type arc welding or laser beam irradiation of focal blurring in which the focal position of the laser beam is shifted upward from the plate surface,
The range of the plate thickness T1 of the upper plate or the lower plate is 2 <T1 ≦ 6 mm,
The range of the plate thickness T2 of the standing plate is 2 to 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1),
The upper plate or the melt width w of the upright plate after penetrating the lower plate, the plate thickness T1 than the size rather formed (w> T1), or through portions of the plate rear surface which is formed on the upper and lower plates Or the welding cross-sectional area A of the standing plate melting width part is formed larger than the plate thickness cross-sectional area B1 of the upper plate or the lower plate (A> B1),
A method for welding an upper and lower T-shaped joint, wherein a solid wire or a strand wire is used as the wire . A method for welding the upper and lower T-shaped joints according to claim 1,
An upper and lower T-shaped joint characterized in that a surface height C of a bead formed on at least one of the upper plate and the lower plate is formed in a convex shape (1 ≦ C ≦ 3 mm) higher by 1 to 3 mm than the plate surface. Welding method. A welding method for upper and lower T-shaped joints according to claim 1 or 2 ,
The arc welding is performed under shield gas using a shield gas supply means for flowing out an inert gas shield gas, or a double shield gas supply means for flowing out an inert gas shield gas and a shield gas containing an oxidizing gas. A method for welding the upper and lower T-shaped joints. It consists of a stainless steel plate with one or two upper and lower plates placed on the top and bottom surfaces of the standing plate. While feeding the wires from the top and bottom surfaces to the standing plate side In the welding method of the upper and lower T-shaped joints for performing laser welding by non-consumable electrode type arc welding or laser beam irradiation of focal blurring in which the focal position of the laser beam is shifted upward from the plate surface,
The range of the plate thickness T1 of the upper plate or the lower plate is 2 <T1 ≦ 6 mm,
The range of the plate thickness T2 of the standing plate is 2 to 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1),
The upper plate or the melt width w of the upright plate after penetrating the lower plate, the plate thickness T1 than the size rather formed (w> T1), or through portions of the plate rear surface which is formed on the upper and lower plates Or the welding cross-sectional area A of the standing plate melting width part is formed larger than the plate thickness cross-sectional area B1 of the upper plate or the lower plate (A> B1),
As the wire, using a flux-cored wire containing a flux agent promoting penetration depth,
The flux agent filled in the flux-cored wire is a powder agent in which an oxide composed of at least TiO ₂ , Cr ₂ O ₃ and SiO ₂ is mixed,
The welding amount of the flux-cored wire to be fed is in the range of 1 g / min to 7 g / min,
The melting width w of the upright plate is formed larger than the plate thickness T1 of the upper plate and the lower plate (w> T1),
The method for welding upper and lower T-shaped joints, wherein the content of oxygen gas contained in the weld metal part is in the range of 100 wt.ppm to 200 wt.ppm . In the welding method of the upper and lower T-shaped joint according to any one of claims 1 to 4 ,
Two upper and lower plates are butt-arranged on both the upper and lower surfaces of the standing plate without gap G or with gap G equal to or less than 0.2 times the plate thickness T1 (0 ≦ G ≦ 0.2 × T1). A welding method for upper and lower T-shaped joints. A first step in which one upper plate and two lower plates are arranged on both upper and lower surfaces of the upright plate, or two are arranged in parallel to form the shape of the upper and lower T-shaped joints;
A second step of welding from the surface of the upper plate to the vertical plate side by the welding method of claim 1 ;
And a third step of welding from the surface of the lower plate facing the upper plate to the vertical plate side by the welding method of claim 1 . The upper and lower surfaces of the vertical plate are made of stainless steel plate with one or two upper and lower plates arranged in abutment, and the focus position of the non-consumable electrode type arc welding or laser beam using a wire Upper and lower T-type welded joints having weld metal parts welded from the surface of the upper plate and the lower plate to the standing plate by laser welding by defocused laser beam irradiation shifted upward from the surface,
The plate thickness T1 range of the upper plate and the lower plate is 2 <T1 ≦ 6 mm,
The plate thickness T2 range of the upright plate is 2 to 5 times the plate thickness T1 (2 × T1 ≦ T2 ≦ 5 × T1),
The melting width w of the standing plate after passing through the upper plate or the lower plate is larger than the plate thickness T1 (w> T1),
Or the weld metal part in which the welding cross-sectional area A of the penetration part of the board back surface of an upper board and a lower board or the melt width part by the side of a standing board is larger than board thickness cross-sectional area B1 of an upper board and a lower board (A> B1) On both upper and lower sides of the T-shaped joint ,
An upper and lower T-type welded joint , wherein at least one of the upper plate and the lower plate is a perforated plate having a plurality of holes formed in advance in a range other than the weld metal portion . In the upper and lower T-shaped welded joint according to claim 7 ,
Arc welding or laser welding using a shield gas supply means for flowing out an inert gas shield gas or a double shield gas supply means for flowing out an inert gas shield gas and a shield gas containing an oxidizing gas An upper and lower T-shaped welded joint. In the upper and lower T-shaped welded joint according to claim 7 ,
The upper and lower T-shaped welded joint, wherein the wire is a solid wire, a strand wire, or a flux-cored wire containing a flux agent that promotes penetration depth. In the upper and lower T-shaped welded joint according to claim 7 ,
An upper and lower T-shaped welded joint, wherein the bead surface height C is formed in a convex shape (1 ≦ C ≦ 3 mm) which is 1 to 3 mm higher than the plate surface. In the upper and lower T-shaped welded joint according to claim 7 ,
The upper and lower T-shaped welded joints are characterized in that the weld metal part is formed by one pass on both upper and lower sides of the T-shaped joint. Used in nuclear devices or thermal devices, a welded structure that are deployed in the environmental conditions in contact with the hot steam medium or corrosive media, the welded structure can be of any claims 7 to 11 in at least a part A welded structure comprising the upper and lower T-shaped welded joints according to claim 1.

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