JP6354941B2 - Method for suppressing groove shrinkage in automatic TIG back wave welding - Google Patents

Description

  The present invention relates to a method for forming a healthy back wave by suppressing thermal contraction of the root interval of a groove portion in automatic TIG back wave welding of a steel butt joint.

Automatic TIG back wave welding of steel butt joints is intended to form a healthy back wave by welding the first layer without using the automatic back TIG welding machine to obtain a fully-penetrated joint. It is said.
FIG. 7 shows an example of an automatic TIG back wave welding method performed in construction of a tank or the like. FIG. 7A shows an example of a butt joint in the vertical direction and FIG. 7B shows a horizontal direction. FIG. 8 is an enlarged cross-sectional explanatory view of the butt joint of FIG. 7 (A) or (B). The members having the same names common to these drawings are given the same reference numerals.
The automatic TIG back wave welding of the butt joint of the steel material 1 shown in FIG. 7 and FIG. 8 is provided with a backing 6 for preventing back wave oxidation on the narrow side of the groove portion 2, and an assembly jig 8 and deformation restraint. This is a welding method in which a large number of jigs 9 are installed, an arc 5b is generated from the electrode 5a of the welding torch 5 from the wide side of the groove portion 2, and the filler rod 12 is melted.

  As a technique relating to welding, for example, Japanese Patent Laid-Open No. 11-156590 “Backing for Welding” of Patent Document 1 is known. In this invention, when the plate materials to be welded are butted on both sides, a contact member having a substantially circular cross section that contacts the root edge of the groove portion and a pressing material that presses the contact material against the groove portion are formed. A backing member is disclosed, and an attachment member such as a portal member or a pressing member is attached in the vicinity of the groove portion.

  Also, Japanese Patent Application Laid-Open No. 2012-115858 of “Patent Document 2”, “Guide part and welding method of welded joint” describes an open butt weld joint of a storage tank side plate assembled on site, which is the upper side of the lower side plate material between the side plate materials. It is disclosed that a convex part is provided on the whole or a part of the front surface and a concave part that fits the convex part is provided on the whole or a part of the groove surface that is the lower side of the upper plate member. ing.

  Japanese Patent Application Laid-Open No. 09-225652 “Electron Beam Welded Joint” of Patent Document 3 describes an insert material which is an intermediate metal medium as a buffer material in an electron beam welded joint of an I-shaped joint made of different materials. In addition, it is also disclosed that welding is performed while being inserted between the metal and the backing metal.

Furthermore, Japanese Patent Application Laid-Open No. 2012-662 “Stainless Steel Plate Welding Method and Welded Joint” of Patent Document 4 includes a method of butt welding stainless steel plates arranged in a vertical direction, wherein the stainless steel plate is an I groove, A ceramic backing material is attached to one side of the welded portion of the stainless steel plate, and the entire plate thickness is welded in one pass by gas shielded arc welding using a flux-cored wire from the opposite side of the one side of the stainless steel plate. It is disclosed.

JP 11-156590 A JP 2012-115858 A JP 09-225652 A JP 2012-662 A

The automatic TIG back wave welding of the butt joint of FIG. 8 which shows the longitudinal direction of FIG. 7 (A), the horizontal direction of FIG. This is a welding method in which an arc 5b is generated from the electrode 5a of the welding torch 5 on the wide side of the welding torch 5 and the filler rod 12 is melted.
In order to efficiently form a high quality back wave by such automatic TIG back wave welding, oxidation of the back wave during welding is suppressed, and the route interval L necessary for forming the back wave of the groove portion 2 is maintained. Is required.
However, in automatic welding in which welding is performed using a large heat input, heat shrinkage increases, so that there is a problem in that the root interval L of the groove portion 2 is greatly shrunk during welding, making it difficult to form a back wave.
As shown in FIGS. 7 and 8, a backing 6 for preventing back-surface oxidation is provided on the narrow side of the groove portion 2 of the steel material 1 and supported by an assembly jig 8. In addition, the deformation restraining jig 9 is provided on the narrow side of the groove portion 2 to suppress the shrinkage of the root interval L during automatic welding, but a large number of deformation restraining jigs 9 are necessary. The work of mounting and removing, the grinding process by the grinder of the jig welded portion 11 trace, the inspection and the repair welding are increased, and the work process is not efficient.
7 and FIG. 8, machining the groove in the U shape instead of the V shape groove makes it easy to perform back wave welding, but requires a specialized processing tool, which requires labor and cost for processing. Is required.
In addition, by inserting spacers at equal intervals in the weld length direction of the groove portion 2, it is possible to secure the route interval L during welding and reduce the number of deformation restraining jigs 9, but the spacer Not only is it impossible to form a back wave in the portion where the spacer is inserted, but the groove portion 2 contracts due to heat shrinkage due to welding, and the spacer 4 cannot be removed.
On the other hand, after welding the wide side of the groove part 2 without performing back wave welding, the first layer welded part is picked up from the side where the width of the groove part 2 is narrow. It is possible to obtain a completely-penetrated joint, but the back side is hung and the back side requires a post-hanging grinder processing step, which is not efficient.
As described above, in order to obtain a back wave in automatic TIG welding of a butt joint, installation of a large number of jigs and specialized processing tools are required, which has a great problem in terms of work process and cost.

  In the invention of “backing for welding” of Patent Document 1 relating to welding, a contact material having a substantially circular cross section that comes into contact with the root edge of the groove portion when the welded plate materials are faced to each other and welded on both sides, and this contact Although a backing formed with a pressing material that presses the material against the groove portion is disclosed, the welding backing is a backing material used when performing multi-layer welding from both the front and back sides of a thick plate. It is not melted by a welding arc and becomes part of the deposited metal to form a back wave.

  In addition, the invention of the “welded joint groove and welding method” in Patent Document 2 describes the shape of the groove of the welded joint of the storage tank side plate, which makes it easy to align, assemble and weld the welded joint on site. Although it is a welding construction method, it relates to a groove forming method for facilitating side plate assembly, and is not a construction method that facilitates back wave formation.

  Further, in the invention of the “electron beam welded joint” of Patent Document 3, an insert material which is an intermediate metal medium is used as a buffer and a backing metal in an electron beam welded joint of an I-shaped joint made of different materials. Although it is disclosed that welding is also inserted between the two, it is a construction method that suppresses the decrease in joint strength due to transverse cracks occurring at the bottom of the joint and dilution of the backing, and heat shrinkage of the groove It is not a construction method for the purpose of suppression.

  Furthermore, Japanese Patent Application Laid-Open No. 2012-662 “Stainless Steel Plate Welding Method and Welded Joint” of Patent Document 4 includes a method of butt welding stainless steel plates arranged in a vertical direction, wherein the stainless steel plate is an I groove, It is disclosed that a ceramic backing material is attached to one side of a welded portion of a stainless steel plate, and a total thickness is welded in one pass by gas shielded arc welding using a flux-cored wire from the opposite side. The present invention relates to a welding method for eliminating deformation and welding distortion, and is not a welding method for the purpose of forming a back wave by the first layer welding of automatic TIG welding.

The present invention has been made in view of the above-described problems of the prior art. The object of the present invention is to prevent the root face portion 3 of the groove portion 2 of the steel material 1 from being thermally contracted by the main welding. It is another object of the present invention to provide a groove shrinkage suppression method for automatic TIG back wave welding that always forms a sound back wave while maintaining the route interval L necessary for the back wave formation.

The groove shrinkage suppression method according to claim 1 is the automatic TIG back wave welding performed by forming the groove portion 2 by abutting the steel material 1A and the steel material 1B, over the entire length in the groove portion 2, and the groove A continuous spacer 4 is provided between the root face portion 3A and the root face portion 3B of the portion 2 and a continuous spacer 4 is provided. The continuous spacer 4 is a filler rod by the heat of the arc 5b from the electrode 5a of the welding torch 5 12 and the keyhole 13 are melted while forming a part of the deposited metal to form a continuous uniform back wave.

The groove shrinkage suppression method for automatic TIG back wave welding according to claim 1, wherein the groove portion 2 provided with the continuous spacer 4 is a V-shaped groove or an X-shaped groove.

Spacer 4 to the continuous, if steel 1A and steel 1B each other of the same material of the automatic TIG penetration welding according to claim 1 or 2, wherein the a same Material and workpieces or filler material A method for suppressing groove shrinkage.

The groove shrinkage suppression method according to claim 1 is the automatic TIG back wave welding performed by forming the groove portion 2 by abutting the steel material 1A and the steel material 1B, over the entire length in the groove portion 2, and the groove A continuous spacer 4 is provided between the root face portion 3A and the root face portion 3B of the portion 2 and a continuous spacer 4 is provided. The continuous spacer 4 is a filler rod by the heat of the arc 5b from the electrode 5a of the welding torch 5 12 is melted while forming a keyhole 13 together with 12 to form a continuous uniform back wave, and welding is performed while suppressing heat shrinkage of the root interval L in the unmelted portion. As a result, it is possible to form a back bead without penetration failure.
The continuous spacer 4 suppresses heat shrinkage of the root interval L in the unmelted portion, and with the steel material 1A and the steel material 1B in the vicinity of the groove portion 2 and the separately supplied filler rod 12 by the heat of the arc 5b. By proceeding with welding while forming the keyhole 13 at the tip of the molten pool 7a, the solidified molten pool 7a forms a back bead, and a complete penetration joint is obtained.
By using the above-mentioned continuous spacer 4 and welding while forming the keyhole 13, the inert gas supplied from the wide side of the groove portion 2 passes through the concave groove of the backing 6 from the keyhole 13. Since it is distributed to cover the surface of the back wave, oxidation of the back wave is suppressed and a high quality back wave bead is obtained.
Therefore, it is possible to obtain a good quality back bead without supplying an inert gas for the back shield.
By adopting this groove shrinkage suppression method, it is possible to reduce or downsize the jig for restraining the thermal shrinkage of welding, and reduce the grinding work by the grinder for jig trace processing, Repair welding can be reduced.
Since the continuous spacer 4 itself becomes the filler material, the amount of the filler material supplied separately can be reduced.

The groove portion 2 of the continuous spacer 4 in the groove shrinkage suppression method for automatic TIG reverse wave welding according to claim 2 is a V-shaped groove or an X-shaped groove. As compared with the conventional groove shrinkage suppression method, the back wave can be easily formed, a completely penetration joint can be obtained, and the cost can be reduced by shortening the construction period. In the case of the X-shaped groove, it is possible to form a good back wave without suspending the back with a thick plate, and it is possible to reduce the cost by shortening the construction period like the V-shaped groove.

Spacer 4 according to claim 3 bevel shrinkage suppression method for an automatic TIG penetration welding according Because if steel 1A and steel 1B each other of the same material which is the same Material and workpieces or filler material, to be welded wood and steel 1A and steel 1B each other Te If odor of the same material is, it is possible to obtain a weld metal containing a proper chemical components.

It is front explanatory drawing of the butt joint of the vertical direction which shows the groove shrinkage | contraction suppression method of the automatic TIG back wave welding which concerns on this invention. It is sectional drawing which looked at FIG. 1 from the upper direction. FIG. 3 is a front view of FIG. 2. It is explanatory drawing which looked at the butt joint of the vertical direction from the side where the width | variety of the groove part 2 is narrow. It is explanatory drawing which looked at the butt joint of the horizontal direction from the side with the narrow width | variety of the groove part. It is sectional drawing which looked at FIG. 5 from the horizontal direction. It is explanatory drawing which shows an example of automatic TIG back wave welding, (A) shows the vertical direction and (B) shows the butt joint of a horizontal direction. FIG. 8 is an explanatory cross-sectional view illustrating an enlarged butt joint of FIGS.

  Embodiment examples of the groove shrinkage suppression method of automatic TIG back wave welding according to the present invention will be described with reference to FIGS. In the drawings, the same, corresponding, or generically possible items will be described with the same reference numerals. The present invention is not limited to the following embodiments. It goes without saying that the embodiments can be changed without departing from the gist of the present invention.

FIG. 1 is an explanatory front view of a longitudinal butt joint showing a groove shrinkage suppression method for automatic TIG back wave welding according to the present invention.
1A and 1B are steel materials, 2 is a groove portion, 3A and 3B are root faces of steel materials 1A and 1B, respectively, and a backing 6 for preventing backside oxidation is installed on the narrow side of the groove portion 2 Then, in order to maintain the route interval L necessary for forming the back wave of the groove portion 2, a continuous spacer 4 is fitted between the route face portion 3A and the route face portion 3B in the groove portion 2. It is installed by tack welding, and an arc 5b is generated by the electrode 5a of the welding torch 5 from the wide side of the groove portion 2 to melt the filler rod 12 and the continuous spacer 4 to melt the first layer weld portion 7. Form.
The continuous spacer 4 has a length that can be fitted between the root face portion 3A and the root face portion 3B in the groove portion 2 over the entire length of the groove portion 2, and a necessary route interval L is set. A width that can be ensured and a thickness that can form the keyhole 13 at the time of melting.
When the steel material 1A and the steel material 1B are made of the same material, the continuous spacer 4 is made of the same material as the material to be welded or the filler material. When the steel material 1A and the steel material 1B are made of different materials, the welded metal Select the one with the appropriate dilution rate.
The continuous spacer 4 is a flat steel, a round steel, a filler wire, or the like, and is melted by the heat of the arc 5b during main welding to form a part of the weld metal between the steel material 1A and the steel material 1B.
The conventional spacer cannot be removed due to compressive force when the root interval L of the groove portion 2 becomes narrow due to heat shrinkage due to welding, but the continuous spacer 4 itself of this groove shrinkage suppression method is used as a filler material. It also has a function and is melted by the arc 5b to form a back wave. Therefore, it does not need to be removed after welding and is easy to handle.

The continuous spacer 4 is applicable not only to the V-shaped groove shown in the figure but also to the root face portion of the X-shaped groove not shown.
When the spacer 4 that is continuous with the V-shaped groove is used, the V-shaped groove processing is easy, and the back wave can be easily formed compared to the conventional case, and a completely-penetrated joint is obtained, and the work period is shortened. The cost can be reduced.
When using the spacer 4 which is continuous to the X-shaped groove of the thick plate, it is possible to obtain a good back wave without defects by complete penetration, so there is no need to hang the back by gouging or grinder, etc. This makes it possible to shorten the construction period and reduce costs.

FIG. 2 is a cross-sectional view of FIG. 1 as viewed from above. Steel 1A, steel 1B, groove 2, root face 3A, root face 3B, continuous spacer 4, welding torch 5, and backing 6 are shown. Show.
The continuous spacer 4 is fitted between the root face portion 3A of the steel material 1A of the groove portion 2 and the root face portion 3B of the steel material 1B and is installed by tack welding. 5a is an electrode, 5b is an arc, and 6a is a backing groove.
A broken line portion 7b indicates a range melted by the arc 5b and solidifies to form the first layer weld portion 7.

FIG. 3 is a front view of FIG. 2 and shows a steel material 1A, a steel material 1B, a groove portion 2, a root face portion 3A, a root face portion 3B, and a continuous spacer 4. FIG.
The continuous spacer 4 is fitted between the root face portion 3A of the steel material 1A of the groove portion 2 and the root face portion 3B of the steel material 1B, and is installed by temporary welding.

Thus, since the continuous spacer 4 is fitted between the root face portion 3A of the steel material 1A and the root face portion 3B of the steel material 1B in the groove portion 2 and welding is performed, the continuous spacer 4 of the unmelted portion is performed. As a result, the root interval L of the groove portion 2 is prevented from being narrowed due to thermal contraction, and the continuous spacer 4 itself and the adjacent steel material 1A, steel material 1B, and filler rod 12 are simultaneously and reliably grooved by the arc 5b. The portion 2 can be melted to the narrow side, and a back wave is easily formed without causing poor penetration.
This groove shrinkage suppression method facilitates the formation of a back wave by automatic TIG welding by fitting a continuous spacer 4 to a V-shaped groove or the like that is easy to process.
The continuous spacer 4 has a length that can be fitted between the root face portion 3A and the root face portion 3B in the groove portion 2 over the entire length of the continuous groove portion 2, and a necessary route interval. Since L is set to a width that can be secured and the thickness is such that the keyhole 13 can be formed at the time of melting, welding can be performed while the keyhole 13 is maintained, and a healthy backside bead can be formed.
In this groove shrinkage suppression method, the continuous spacer 4 suppresses the heat shrinkage of the root interval L in the unmelted portion, and the steel material 1A and the steel material 1B in the vicinity of the groove portion 2 are separately supplied by the heat of the arc 5b. The weld pool 7a becomes the molten pool 7a together with the rod 12, and welding is advanced while forming the keyhole 13 at the tip of the molten pool 7a, so that the solidified molten pool 7a forms a back bead and a complete penetration joint is obtained.
Inert gas supplied from the wide side of the groove portion 2 by performing welding in the direction of the arrow while forming the keyhole 13 at the tip of the molten pool 7a using the continuous spacer 4 described above. Is distributed from the keyhole 13 to the concave groove of the backing 6 to cover the surface of the back wave, so that oxidation of the back wave is suppressed and a good quality back bead is obtained.
Therefore, it is possible to obtain a good quality back bead without supplying an inert gas for the back shield.

When the steel material 1A and the steel material 1B are made of the same material, it is possible to obtain a weld metal containing an appropriate chemical component by using a continuous spacer 4 made of the same material as the material to be welded or the filler material. .
When the steel material 1A and the steel material 1B are different materials, it is possible to obtain a weld metal containing an appropriate chemical component by selecting and using a continuous spacer 4 made of a material with an appropriate dilution ratio of the weld metal. is there.
Therefore, in this groove shrinkage suppression method, it is possible to obtain a high-quality weld metal that does not crack even when the steel material 1A and the steel material 1B, which are welded materials, are the same material or different materials.

FIG. 4 is an explanatory view of the longitudinal butt joint viewed from the side where the width of the groove portion 2 is narrow. The steel material 1A, the steel material 1B, the groove portion 2, the continuous spacer 4, the welding torch 5, the backing 6, An assembly jig 8, a deformation restraining jig 9, and a wedge 10 are shown, and the detailed structure thereof has been described with reference to FIGS.
Thus, by using the continuous spacer 4, the deformation restraining jig 9 for preventing thermal shrinkage due to welding can be reduced or downsized as compared with the conventional one, and grinding work by a jig trace processing grinder can be performed. This makes it possible to reduce inspection and repair welding of the relevant part.

FIG. 5 is an explanatory view of the horizontal butt joint viewed from the side where the width of the groove portion 2 is narrow.
A continuous spacer 4 is temporarily welded to the groove portion 2 of the horizontal joint of the steel material 1C and steel material 1D, and the backing 6, the assembly jig 8, and the deformation restraining jig are mounted on the narrow side of the groove portion 2. 9. A wedge 10 is installed, and welding is performed with a welding torch 5 from the surface side.
Thus, by using the continuous spacer 4, the deformation restraining jig 9 for preventing thermal shrinkage due to welding can be reduced or downsized as compared with the conventional construction method, and grinding by a jig trace processing grinder. Work can be reduced, and inspection and repair welding of the relevant part can be reduced.

FIG. 6 is a cross-sectional view of FIG. 5 viewed from the lateral direction.
Between the root face portion 3C of the steel material 1C and the root face portion 3D of the steel material 1D, which are located at the top and bottom of the steel joint 1C and 1D, the groove portion 2 of the horizontal joint, the continuous spacer 4 is fitted and temporarily welded. The backing 6 is put on the side where the width of the groove portion 2 is narrow, and welding is performed with the welding torch 5 from the side where the width of the groove portion 2 is wide.
5a is an electrode, 5b is an arc, and 6a is a backing groove.
A broken line portion 7b indicates a range to be melted by the arc 5b and solidifies to form the first layer weld portion 7.

The groove shrinkage suppression method for automatic TIG back wave welding of the present invention can be applied to various welding structures that require back wave formation.

1 Steel
2 groove part
3 Route face part
4 consecutive spacers
5 Welding torch
6 backing
7 First layer weld
8 Assembly jig
9 Deformation restraint jig
10 wedges
11 Jig welded part
12 Filler rod
13 Keyhole

Claims (3)

In the automatic TIG back wave welding performed by forming the groove portion 2 by abutting the steel material 1A and the steel material 1B, the root face portion 3A and the root face portion 3B of the groove portion 2 extend over the entire length in the groove portion 2. The continuous spacer 4 is melted while forming the keyhole 13 together with the filler rod 12 by the heat of the arc 5b from the electrode 5a of the welding torch 5. A method for suppressing groove shrinkage in automatic TIG back wave welding, which is a part of the weld metal and forms a continuous uniform back wave. The groove shrinkage suppression method for automatic TIG back wave welding according to claim 1, wherein the groove portion 2 provided with the continuous spacer 4 is a V-shaped groove or an X-shaped groove. Spacer 4 to the continuous, if steel 1A and steel 1B each other of the same material of the automatic TIG penetration welding according to claim 1 or 2, wherein the a same Material and workpieces or filler material A method for suppressing groove shrinkage.

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