JP2011189363A - Horizontal gas shield arc welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a horizontal gas shield arc welding method capable of carrying out butt welding of box pillars used for construction of a building or the like and horizontal multi-layer welding of an end of a column and a diaphragm efficiently in a good working environment and capable of obtaining a high quality welding part. <P>SOLUTION: The gas shield arc welding method is directed for carrying out multi-layer welding of a beveling part of a square pillar-shaped construction in a horizontal posture. The beveling part of the square pillar-shaped construction is a bevel groove with a backing metal, has a root gap of 2-5 mm, and is made to be a chevron type or a V type bevel groove with a bevel angle of 25-35&deg;. A steel tab with a plate thickness of 2-6 mm is mounted in a bevel groove of each corner part. A copper cooling member is arranged so as to contact with the back surface side of the beveling part to which the steel tab is welded and then the gas shield arc welding is carried out in a horizontal posture. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a lateral gas shielded arc welding method in which diaphragms are welded in a lateral posture with high efficiency in abutting between box columns used for building construction or the like and in an end portion of a column.

  If the diaphragm cannot be welded by butt welding the box columns or tilting the column, welding is performed in a horizontal orientation using solid wires. Usually, the welded joint is a grooved groove with a backing metal, the groove angle is set to 35 °, and the root interval is set to around 7 mm. In this horizontal welding, if the groove cross-sectional area is excessively reduced, or if the amount of welding per pass is increased, the probability of occurrence of poor fusion and slag entrainment defects increases. The current situation is that multi-pass construction under small heat input conditions is performed in the groove cross-sectional area. Originally, transverse welding has a lower welding efficiency than the downward and vertical postures, and it can be said that the welding is highly difficult in terms of construction.

  FIG. 1 is a perspective view in which box columns are butted against each other, and FIG. Grooves a, b, c and d are provided outside the upper member 1 and the lower member 2 of the box column, and a steel backing metal 3 is attached to the back side of the groove, and a root gap is formed by an erection piece or the like. The upper member 1 is provided and fixed to the lower member 2. Welding is performed simultaneously with groove part a or groove part a and groove part b by gas shield arc welding in a horizontal posture using a solid wire. When the groove portion a and the groove portion b are multilayered and welded up to the final pass, the welding of the groove portion a and the groove portion b was multilayered for the purpose of preventing the occurrence of welding defects. Both ends of the welded part are cut into a predetermined shape by gouging. Next, multilayer welding is performed on the groove portion c and the groove portion d to complete the welding.

  However, when welding is performed by the conventional welding method, it is necessary to cut both end faces of the welded portion of the groove portion a and the groove portion b, which have been welded, into a predetermined shape by gouging. In addition, the gouging work has a very bad working environment because of many noises and powder scattering.

  As a technique for solving the above-mentioned problem, for example, in Japanese Patent Application Laid-Open No. 6-297144 (Patent Document 1), a ceramic tab is attached to the start and end of a groove portion, and a multi-layered gas shield with a lateral orientation between both tabs. There is a description of a technique of performing arc welding and damming the weld metal with a tab.

  When multi-layer welding is performed by the technique described in Patent Document 1, it is not necessary to scrape both end surfaces of the welded portion of the groove portion that are multi-layer welded by gouging, but ceramic remains on the uneven portion of the end surface of the welded portion. It is necessary to finish with a grinder. Further, in the final layer, the beads are likely to sag, and in order to prevent the sag of the beads, the welding is performed at a low current and a high welding speed, but there is a problem that welding defects such as slag entrainment defects are likely to occur. Furthermore, when performing automatic welding, since an arc cannot be generated on the ceramic, it is necessary to perform a complicated operation such as a backstep method.

  On the other hand, as a technique for obtaining a clean front bead with no bead sag by the horizontal multi-layer gas shielded arc welding method, for example, Japanese Patent Laid-Open No. 8-267235 (Patent Document 2) discloses a technique in which a flux-cored wire is applied. JP-A-6-640 (Patent Document 3) discloses a technique to which a high-speed rotating arc is applied, and JP-A-10-314985 (Patent Document 4) discloses a technique in which a front cover material is arranged. There is.

  However, the technique described in Patent Document 2 has a problem that when multi-layer welding is performed in a lateral orientation using a flux-cored wire, the penetration tends to become shallow and slag entrainment defects are likely to occur. In addition, the technique described in Patent Document 3 requires a special welding device and is expensive. Furthermore, the technique described in Patent Document 4 can prevent the bead sagging in the first layer of the final layer, but there is a problem that the weld bead in the subsequent layers tends to sag.

JP-A-6-297144 JP-A-8-267235 JP-A-6-640 JP-A-10-314985

  The present invention obtains a high-quality and high-quality welded part in a favorable working environment by butt-matching box columns used in building construction, etc., and column-by-side multi-layer welding of a diaphragm and a diaphragm. An object of the present invention is to provide a lateral gas shielded arc welding method capable of performing the following.

  The gist of the present invention is a gas shielded arc welding method in which a groove portion of a quadrangular columnar structure is multi-layer welded in a lateral orientation, wherein the groove portion of the quadrangular columnar structure is a groove with a backing metal, and a route interval is 2 -5 mm, groove angle of 25-35 ° lave or V-shaped groove, and a steel tab with a plate thickness of 2-6 mm is mounted in each corner groove, and the groove portion where the steel tab is welded A copper cooling member is provided so as to be in contact with the back surface side of the steel plate and welded.

  C: 0.02-0.08 mass%, Si: 1.0-1.7 mass%, Mn: 1.8-2.8 mass%, Si + Mn: 3.2-4.1 mass% The other is a lateral gas shielded arc welding method characterized by welding using solid wire which is Fe and inevitable impurities.

  According to the horizontal gas shielded arc welding method of the present invention, since steel tabs are attached in each corner groove of a quadrangular columnar structure and multilayer build-up welding is performed, there is no need to process the end face of the welded portion, and the working environment Improves welding efficiency.

  Further, since the route interval and the groove angle are narrowed, the welding time can be shortened and the welding efficiency is further improved.

  Furthermore, since the components of the solid wire to be used are limited, welding defects and weld beads are not drooped, and a high-quality weld can be obtained.

It is the perspective view which matched the box pillars. It is sectional drawing which shows the state which looked downward from the groove | channel cross section of FIG. It is sectional drawing which shows the state which looked at the embodiment of the horizontal gas shield arc welding method of this invention from the groove | channel cross section of FIG. It is sectional drawing which shows the groove shape which faced box columns. It is sectional drawing which shows the groove shape which contact | abutted the diaphragm to the edge part of the column. The lamination example of the multilayer build-up welding in the Example of this invention is shown.

  In order to solve the above-mentioned problems, the present inventors have worked by multi-layer gas shield arc welding in a lateral orientation to butt the box columns used for building construction or the like and to weld the column end and the diaphragm. We investigated in detail the welding method that can obtain a welded part with high efficiency and no weld defects without harming the environment.

  As a result, a steel tab that does not need to be removed after welding with a copper cooling member in contact with the corner groove of each groove is attached, reducing the groove cross-sectional area and limiting the components of the solid wire used Thus, the present inventors have found a multi-layered horizontal gas shielded arc welding method that does not harm the work environment and has no welding defects.

  Hereinafter, the present invention will be described in detail.

  FIG. 1 is a perspective view in which box columns are butted together, and FIG. 3 is a cross-sectional view showing a state in which the embodiment of the horizontal gas shield arc welding method of the present invention is viewed from the groove cross section of FIG.

  In the present invention, a lave or V-shaped groove portion a, b, c, d is provided outside the upper member 1 and the lower member 2 of the box column, and a steel backing metal is provided on the back side of the groove portion. 3 is attached, and a root gap is provided by an erection piece or the like to fix the upper member 1 to the lower member 2. Next, steel tabs 4a, 4b, 4c, and 4d that are matched to the plate thickness t and the groove shape are mounted in the corner grooves of the groove portions a, b, c, and d, and the steel tabs 4a and 4b are attached. Copper cooling members 5a, 5b, 5c, and 5d are provided so as to be in contact with the back surface side of the groove portions 4c and 4d to be welded. Welding is performed simultaneously with groove part a or groove part a and groove part b by gas shield arc welding in a horizontal posture using a solid wire. If welding is performed at the same time, in addition to the efficiency surface, it is possible to prevent the root interval deformation of the unwelded groove due to welding shrinkage only in one direction. When the groove part a and the groove part b are multilayered and welded to the final pass, the groove part c and the groove part d are multilayered and welded except for the copper cooling members 5a, 5b, 5c and 5d. To complete the welding.

  As shown in FIG. 4, the groove portion is a groove with a steel backing metal 3, the root interval 6 is 2 to 5 mm, and the groove angles are the upper member 1 side groove angle θ1 and the lower member side groove angle θ2. A total of 25 to 35 ° is a lave or V-shaped narrow groove.

  When the root interval 6 of the groove portion is less than 2 mm, the steel backing metal 3 cannot be sufficiently melted by the first layer welding. On the other hand, when the route interval 6 exceeds 5 mm, the groove cross-sectional area becomes large and the welding efficiency decreases.

  If the sum of the upper member 1 side groove angle θ1 and the lower member side groove angle θ2 is less than 25 °, the nozzle does not enter the groove even if the nozzle portion (not shown) of the welding torch is flattened. When the plate thickness t is thick, the protruding length of the wire becomes long, and blow holes are likely to occur due to insufficient shielding. Moreover, the upper member 1 side cannot be melt | dissolved enough and a slag entrainment defect may arise. On the other hand, when the total of the upper member 1 side groove angle θ1 and the lower member side groove angle θ2 exceeds 35 °, the groove cross-sectional area increases and the welding efficiency decreases.

In addition, it is preferable that upper member 1 side groove angle (theta) 1 is 10 degrees or more from defect resistance.
FIG. 5 shows a groove sectional view when the diaphragm 8 is brought into contact with the end of the column 7. When the diaphragm 8 is brought into contact with the end of the column 7, a groove with a steel backing metal 3 having a root interval 6 of 2 to 5 mm and a column 7 side groove angle θ1 of 25 to 35 ° The narrow gap.

  The plate thickness of the steel tabs 4a, 4b, 4c, and 4d to be installed in each corner groove of the groove portions a, b, c, and d is 2 to 5 mm. If the plate thickness of the steel tabs 4a, 4b, 4c, and 4d is less than 2 mm, the welding arc penetrates to the copper cooling members 5a, 5b, 5c, and 5d provided in contact with the back side, and the weld bead hangs down. The copper cooling members 5a, 5b, 5c, and 5d are melted and cracks occur in the weld metal. On the other hand, if the plate thickness exceeds 6 mm, the surfaces in contact with the groove surfaces of the steel tabs 4a, 4b, 4c, and 4d cannot be completely melted by the arc from both sides, and the steel tabs 4a, 4b, 4c and 4d need to be removed by gouging or the like, or a steel tab needs to be completely welded and attached, resulting in poor efficiency.

The copper cooling members 5a, 5b, 5c, and 5d in contact with the back side of the welded groove portion of the steel tabs 4a, 4b, 4c, and 4d prevent overheating of the steel tabs 4a, 4b, 4c, and 4c due to arcing. Thus, the weld metal is prevented from being melted down.
Next, the reasons for limiting the components of the solid wire used in the horizontal gas shield arc welding method of the present invention will be described.

  The C of the solid wire is 0.02% by mass or more from the reduction of spatter generation amount and 0.08% by mass or less from the hot cracking resistance.

  Si and Mn increase the viscosity of the molten metal to reduce oxygen and prevent bead sag in lateral orientation welding.

  When the Si content is less than 1.0% by mass, the viscosity of the molten metal is lowered, the beads are dripped, and slag entrainment defects are likely to occur in the intermediate layer, and the bead appearance is poor in the final layer. On the other hand, if it exceeds 1.7 mass%, the arc becomes unstable and the amount of spatter generated increases. Moreover, since the amount of slag generation increases, it takes time to remove the slag and the welding efficiency is deteriorated. Therefore, Si is 1.0 to 1.7 mass%.

  In narrow groove welding, the protruding length of the wire is set to be particularly long in the lower layer portion, and blow holes are likely to occur due to insufficient shielding, so that a relatively large amount of Mn is contained to prevent the occurrence of blow holes. If Mn is less than 1.8% by mass, the effect of preventing the generation of blowholes cannot be obtained. On the other hand, if Mn exceeds 2.8% by mass, the arc becomes unstable and the amount of spatter generated increases. Moreover, since the amount of slag generation increases, it takes time to remove the slag and the welding efficiency is deteriorated. Therefore, Mn is set to 1.8 to 2.8% by mass.

  Further, when the total amount of Si and Mn is less than 3.2% by mass, the viscosity of the molten metal is lowered, the beads are dripped, and slag entrainment defects are easily generated in the intermediate layer, and the bead appearance is poor in the final layer. On the other hand, if the total of Si and Mn exceeds 4.1% by mass, the familiarity of the bead toe portion becomes poor and slag entrainment defects are likely to occur. Moreover, since the amount of slag generation increases, it takes time to remove the slag and the welding efficiency is deteriorated. Therefore, Si + Mn is set to 3.2 to 4.1% by mass.

  Other inevitable impurities P and S are each preferably 0.02% by mass or less in view of crack resistance. The wire diameter is preferably 1.2 mm or 1.4 mm, and the welding conditions are preferably a welding current of 250 to 400 A and a welding speed of 25 to 50 cm / min in consideration of work efficiency.

  In addition, by setting the torch angle in the lateral gas shielded arc welding method of the present invention to 10 to 15 °, the wire aiming position is stable and preferable from the viewpoint of welding defect resistance. The shielding gas can be carbon dioxide or argon gas mixed with 10 to 50% by volume carbon dioxide. In consideration of the amount of slag generated, argon gas is mixed with 10 to 30% by volume carbon dioxide. It is preferable to use the prepared gas.

  In addition, when welding is performed outdoors or indoors where the wind blows, it is preferable to use a windproof jig that covers the welding work place with a curtain or covers the entire groove portion on one side of the welded portion in order to prevent the occurrence of blowholes.

  Furthermore, as a welding power source, a type having a constant voltage characteristic by thyristor or inverter control can be used. However, when the above mixed gas is used, a pulse power source may be used in consideration of the amount of penetration. .

  Hereinafter, the effect of the present invention will be described in detail with reference to examples. JIS G3136 SN490B steel, 45 mm thick plate columns shown in FIG. 1, each side of which is 1100 mm butting each other, the various groove-shaped portions shown in Table 1 with a 12 mm thick backing metal are shown in Table 2. Welding was performed using a solid wire having a wire diameter of 1.2 mm. The welding conditions were the standard welding conditions shown in Table 3. In addition, the lamination example of the multilayer build-up welding in the Example of this invention is shown in FIG.

また、各角部開先内に表１に示す板厚の鋼製タブを開先形状に合わせて加工して取付け、鋼製タブの溶接する開先部の裏面側に接するように銅製の冷却部材を設けて、開先部ａと開先部ｂを同時に多層盛溶接して最終パスまで溶接し、銅製の冷却部材を除いて開先部ｃおよび開先部ｄを同時に多層盛溶接を行った。なお、溶接はボックス柱の上部材にレールを取付けて台車に溶接トーチを搭載した溶接機で行った。

In addition, a steel tab having the thickness shown in Table 1 is processed and attached in each corner groove according to the groove shape, and is cooled by copper so as to be in contact with the back side of the groove portion to be welded of the steel tab. A member is provided, and the groove portion a and the groove portion b are simultaneously multilayer welded and welded to the final pass, and the groove portion c and the groove portion d are simultaneously multilayer welded except for the copper cooling member. It was. The welding was performed with a welding machine in which a rail was attached to the upper member of the box column and a welding torch was mounted on the carriage.

  The survey items were observation of welding workability and bead appearance during welding, time from the start to the end of welding, and the presence or absence of welding defects due to ultrasonic flaw detection after welding. The results are also summarized in Table 1.

  The welding time was the longer of the welding times of the groove portions a and b and the groove portions c and d. The set time of the rail to the upper member of the box column and the welding machine was excluded, and the time from the start of welding to the end of the final pass welding was used. The welding time was good within 4 hours.

  In Table 1, Test No. 1 to Test No. 5 are examples of the present invention, and Test No. 6 to Test No. 12 are comparative examples. Test No.1 to Test No.5, which are examples of the present invention, have a route interval, a groove angle, a steel tab plate thickness is appropriate, and a copper-side cooling member on the back surface side of the groove portion where the steel tab is welded. Furthermore, since the components of the solid wire used were appropriate, the welding workability was good, the welding time was short, and there were no defects in the welded part, which was a very satisfactory result.

  In comparative example test No. 6, the root interval was narrow, so that poor penetration occurred in the first layer. Also, since the Mn of the solid wire used was small, blow holes were generated in the first layer and the second pass.

  In Test No. 7, the root interval was wide, so the welding time was long. Further, since the solid wire used had less Si, the bead dripped and a slag entrainment defect occurred.

  In Test No. 8, since the groove angle was narrow, even when a flat nozzle was used from the first layer to the lower layer, the wire protrusion length became longer and a blow hole was generated in the lower layer. In addition, since the solid wire used had a large amount of Si, the arc was unstable, the amount of spatter generation was large, and the amount of slag generation was also large.

  In Test No. 9, since the total of the groove angles θ1 and θ2 was wide, the welding time was increased. Further, since the solid wire used had a small amount of Si + Mn, the bead dripped and a slag entrainment defect occurred.

  In Test No. 10, since the steel tab was thin, the arc penetrated to the copper cooling member. Therefore, it took time for repair welding, and the welding time became longer. In addition, the amount of spatter generated was large because C of the solid wire used was small. Further, since the amount of Si + Mn is large, the amount of slag generated is increased, and it takes time to remove the slag.

  In Test No. 11, since the steel tab was thick, an unmelted portion was formed in the portion in contact with the groove surface. Further, since the solid wire used had a large amount of Mn, the arc was unstable, the amount of spatter generation was large, the amount of slag generation was also large, and it took time to remove the slag, so the welding time was long.

  In Test No. 12, since the copper cooling member was not in contact with the steel tab, the steel tab was melted down, and it took time for repair welding, and the welding time became longer. Moreover, since there was much C of the solid wire used, the hot crack occurred in the first layer.

DESCRIPTION OF SYMBOLS 1 Upper member 2 Lower member a, b, c, d Groove part 3 Steel backing metal 4a, 4b, 4c, 4d Steel tab 5a, 5b, 5c, 5d Copper cooling member 6 Route space | interval (theta) 1 Upper member Side groove angle (column side groove angle)
θ2 Lower member side groove angle 7 Column 8 Diaphragm

Claims (2)

In the gas shielded arc welding method in which the groove portion of the square columnar structure is multi-layered in a horizontal orientation, the groove portion of the square columnar structure is a groove with a backing metal, the root interval is 2 to 5 mm, and the groove angle Is a 25-35 ° ladle or V-shaped groove, and a steel tab having a thickness of 2 to 6 mm is attached to each corner groove so that the steel tab contacts the back side of the groove portion to be welded. A horizontal gas shielded arc welding method, wherein a copper cooling member is provided for welding. C: 0.02-0.08 mass%, Si: 1.0-1.7 mass%, Mn: 1.8-2.8 mass%, Si + Mn: 3.2-4.1 mass% contained The transverse gas shielded arc welding method according to claim 1, wherein welding is performed using Fe and a solid wire that is an inevitable impurity.

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