JP7603511B2 - Method and device for correcting butt welded joints - Google Patents

Description

The present invention relates to a method for correcting butt welded joints in which the base material is stainless steel plate, and a device for correcting butt welded joints.

When butt welding is performed on a base material made of stainless steel plate, the base material may undergo welding deformation at the welded joint after welding, mainly due to thermal contraction in the direction of the weld line.

When viewed from the welding torch side, welding deformation of the base material can be so-called angular distortion, in which the weld line forms a V-shape as the valley line, buckling distortion, in which the base material curves along the weld line so that it protrudes toward the welding torch, or a combination of these. This type of welding deformation can be reduced to some extent by restraining the base material during welding, but there is a limit to how much deformation can be reduced.

In order to correct welding distortion, a correction process may be carried out on the welded joint after welding. Conventional methods for correction include local heating and hammering. However, the local heating method is difficult to apply to stainless steel due to concerns about high-temperature oxidation and sensitization. In addition, the hammering method requires the worker to have experience and skill, and has the problem of being unable to adequately handle complex distortions.

There is also a method of straightening the deformed welded joint by applying pressure with a roll. Patent Document 1 describes a method of removing welding deformation in which small rollers are used to sufficiently cool only the high residual stress areas near the weld bead, and in a state where residual stress is generated, a sufficiently large pressure is applied in the thickness direction of the plate base material. Patent Document 2 describes a method of applying roll pressure to the plate part in a range of 30 mm from the weld boundary parallel to the weld in a butt welded joint of aluminum and its alloy plates.

However, in the case of stainless steel plates, significant angular distortion and buckling deformation can occur due to low thermal conductivity, and sufficient correction is difficult to achieve using the methods described in Patent Document 1 and Patent Document 2.

Japanese Unexamined Patent Publication No. 52-41144 Japanese Patent Application Publication No. 8-39285

The present invention was made in consideration of the above circumstances, and aims to provide a method and device for correcting butt welded joints that can sufficiently correct welding distortion in butt welded joints whose base material is stainless steel plate.

[1] A method for correcting a butt welded joint having a pair of base materials and a welded portion made of stainless steel plates, comprising:
For each of the pair of base metals, a rolling roll is brought into contact with both sides of the base metal in a thickness direction within a region on the surface of the base metal that is 10 mm or more away from a boundary between the welded portion and the base metal and within 25 mm of the boundary, and the base metal is rolled along the longitudinal direction of the welded portion ;
A method for correcting a butt welded joint , in which a crown roll having a roll surface bulging in an arc shape is used as the rolling roll .
[ 2 ] A method for correcting a butt welded joint having a pair of base materials and a welded portion made of stainless steel plates, comprising:
For each of the pair of base metals, a rolling roll is brought into contact with both sides of the base metal in a thickness direction within a region on the surface of the base metal that is 10 mm or more away from a boundary between the welded portion and the base metal and within 25 mm of the boundary, and the base metal is rolled along the longitudinal direction of the welded portion;
The welded portion is pressed by a straightening roll or a straightening jig from the side where the welded portion protrudes due to angular distortion against the butt welded joint being rolled by the rolling roll,
a distance between the boundary end face of the rolling roll and the boundary is set to a dimension equal to or greater than a plate thickness of the base material during the rolling .
[3] The method for correcting a butt welded joint according to [1] or [2], wherein the reduction ratio in rolling the base metal by the reduction rolls is 0.5 to 2.0%.
[4] A method for correcting a butt welded joint having a pair of base materials and a welded portion made of stainless steel plates, comprising:
a first step of rolling the base metal along the longitudinal direction of the weld by contacting a rolling roll with both sides of the base metal in a thickness direction of the base metal in a region of the base metal surface that is 10 mm or more away from a boundary between the weld and the base metal and within 25 mm of the boundary;
a second step of rolling the base material along the longitudinal direction of the welded portion by the rolling rolls while contacting the region with rolling rolls from both sides in the plate thickness direction of the base material and pressing the welded portion with a straightening roll or a straightening tool from the side where the welded portion protrudes due to angular deformation;
Equipped with
A method for correcting a butt welded joint, wherein during the rolling in the first step and the second step, a distance between the end face of the rolling roll on the boundary side and the boundary is set to be equal to or greater than a dimension corresponding to a plate thickness of the base material.
[5] In the rolling of the base material by the rolling rolls in the first step, the rolling reduction is 0.5 to 2.0%,
The method for correcting a butt welded joint according to [4], wherein the rolling reduction rate in the rolling of the base material by the rolling rolls in the second step is 0.1 to 2.0%.
[6] The method for correcting a butt welded joint according to any one of [ 2 ] to [5], wherein a crown roll having a roll surface bulging in an arc shape is used as the rolling roll.
[7] A device for correcting a butt welded joint comprising a pair of base materials and a welded portion made of stainless steel plates, comprising:
For each of the pair of base metals, a rolling roll is provided that contacts the base metal from both sides in a plate thickness direction within a region that is 10 mm or more away from a boundary between the welded portion and the base metal on the surface of the base metal and within 25 mm from the boundary, and rolls the welded portion along a longitudinal direction ,
1 is a schematic diagram showing a straightening apparatus for a butt welded joint according to the first embodiment of the present invention ;
[8] A device for correcting a butt welded joint having a pair of base materials and a welded portion made of stainless steel plates, comprising:
For each of the pair of base metals, a rolling roll is provided that contacts the base metal from both sides in a plate thickness direction within a region that is 10 mm or more away from a boundary between the welded portion and the base metal on the surface of the base metal and within 25 mm from the boundary, and rolls the welded portion along a longitudinal direction,
A straightening device for a butt welded joint , comprising a straightening roll or a straightening tool that presses the welded portion from the side where the welded portion protrudes due to angular distortion against the welded joint being rolled by the rolling rolls.
[9] The apparatus for straightening a butt welded joint according to [8] , wherein the rolling roll is a crown roll having a roll surface bulging in an arc shape.

According to the findings of the inventor, when buckling deformation occurs, in each of the pair of base materials of a butt welded joint, the difference between the longitudinal residual stress of the weld on the surface side of the base material and the longitudinal residual stress of the weld on the back side opposite the surface becomes large in an area 10 to 25 mm away from the boundary between the weld and the base material on the surface of the base material. Therefore, in the present invention, rolling is performed on this area from both sides in the thickness direction of the base material using rolling rolls. This makes it possible to correct the buckling deformation in the butt welded joint. In addition, the correction method of the present invention can perform sufficient correction compared to the conventional correction method using roll pressure. Furthermore, since the present invention does not require heating of the base material, it can be suitably applied to butt welded joints made of stainless steel plates. Furthermore, since the present invention does not involve hammering on the base material, no skill is required from the worker and it can also handle welding deformations of complex shapes.

In addition, according to the present invention, by pressing the welded portion with a straightening roll or straightening tool from the side where the welded portion protrudes due to angular distortion while the welded joint is being rolled by the rolling roll, the angular distortion can be corrected as well as the buckling distortion. In addition, by leaving a distance between the boundary end face of the rolling roll and the boundary that is equal to or greater than the thickness of the base material, it is possible to prevent the base material of the welded joint pressed by the straightening roll or straightening tool from coming into contact with the end face of the rolling roll on the opposite side of the straightening roll or straightening tool across the welded joint.

Next, according to the correction method of the present invention, for example, in a butt welded joint where both buckling and angular distortion have occurred and the amount of buckling distortion has become large, the buckling distortion is corrected by performing a first step of rolling the above-mentioned area of the base material with a rolling roll, and then performing a second step of rolling the above-mentioned area of the base material with a rolling roll and pressing the welded portion with a roll or a jig, thereby correcting the buckling distortion and angular distortion, and more reliably correcting the welding distortion.

In addition, the straightening device of the present invention makes it easy to straighten welded joints that have been deformed by welding.

FIG. 1 is a perspective view showing an example of a butt welded joint to be subjected to the method for correcting a butt welded joint of the present invention. FIG. 2 is a diagram for explaining the method for correcting a butt welded joint according to the first embodiment of the present invention, and is a front view seen from the conveying direction of the welded joint. FIG. 3 is a perspective view showing a butt welded joint corrected by the correction method of the first embodiment of the present invention. FIG. 4 is a distribution diagram showing the distribution of residual stress on the surface side of a butt welded joint before correction. FIG. 5 is a distribution diagram showing the distribution of residual stress on the back side of a butt welded joint before correction. FIG. 6 is a perspective view showing another example of a butt welded joint to be subjected to the method for correcting a butt welded joint of the present invention. FIG. 7 is a diagram for explaining a method for correcting a butt welded joint according to a second embodiment of the present invention, and is a front view seen from the conveyance direction of the welded joint. FIG. 8 is a diagram for explaining a method for correcting a butt welded joint according to a second embodiment of the present invention, and is a side view seen from the side in the conveyance direction of the welded joint. FIG. 9 is a perspective view showing a butt welded joint corrected by the correction method according to the second embodiment of the present invention. FIG. 10 is a diagram for explaining a method for correcting a butt welded joint according to a third embodiment of the present invention, and is a front view seen from the traveling direction of the rolling rolls. FIG. 11 is a side view seen from the side in the traveling direction of the rolling rolls, illustrating an example of a method for correcting a butt welded joint according to the third embodiment of the present invention. FIG. 12 is a side view seen from the side in the traveling direction of the rolling rolls, for explaining another example of the method for correcting a butt welded joint according to the third embodiment of the present invention. FIG. 13 is a perspective view showing another example of a butt welded joint to be subjected to the method for correcting a butt welded joint of the present invention. FIG. 14 is a front view seen from the traveling direction of the rolling rolls, illustrating a first step of the method for correcting a butt welded joint according to the fourth embodiment of the present invention. FIG. 15 is a perspective view showing a butt welded joint after the first step. FIG. 16 is a front view seen from the conveying direction of the welded joint, illustrating a second step of the method for correcting a butt welded joint according to the fourth embodiment of the present invention. FIG. 17 is a side view showing the butt welded joint after the second step.

Below, an embodiment of the method for correcting a butt welded joint of the present invention will be described with reference to the drawings. In the following description, a "butt welded joint" may be referred to as a "welded joint," and a "method for correcting a butt welded joint" may be referred to as a "correction method."

(First embodiment)
First, a welded joint to be subjected to the straightening method of the present embodiment will be described. FIG. 1 is a perspective view showing an example of a welded joint to be subjected to the straightening method of the present embodiment. The welded joint 100 shown in FIG. 1 includes a pair of base materials 101 made of stainless steel plates and a welded portion 102. The type of stainless steel plate constituting the base material 101 is not particularly limited, and may be any of an austenitic stainless steel plate, a ferritic stainless steel plate, a martensitic stainless steel plate, and a ferritic-austenitic duplex stainless steel plate, but is particularly suitable for use with a welded joint made of an austenitic stainless steel plate. Austenitic stainless steel plates have a relatively low thermal conductivity and tend to be prone to welding deformation, and are therefore particularly suitable as a target for the straightening method of the present invention. In addition, the base material 101 is preferably a thin steel plate having a plate thickness of 4 mm or less that can be welded in a single layer.

The welded portion 102 is a butt welded portion formed by butting the ends of each base material 101 together and welding them. In FIG. 1, the upper surface of the base material 101 is called the front surface 101a, and the lower surface of the base material 101 is called the back surface 101b. The welded joint 100 shown in FIG. 1 is formed by butting two base materials 101, 101 together and welding them while applying heat from the front surface 101a side with a welding torch. In the welded joint 100 shown in FIG. 1, buckling deformation occurs after butt welding. The buckling deformation in the welded joint 100 shown in FIG. 1 is a welding deformation in which the base material 101 curves so as to protrude toward the welding torch along the longitudinal direction of the welded portion 102.

Next, the straightening method of this embodiment will be described. FIG. 2 is a front view of the weld joint from the conveying direction, which is a diagram for explaining the straightening device and the straightening method of this embodiment. In the straightening method of this embodiment, as shown in FIG. 2, a straightening device 1 is used that is equipped with a rolling roll 2 that contacts the base material 101 from both sides in the plate thickness direction and rolls the base material 101 along the longitudinal direction of the welded portion 102. The rolling roll 2 is configured to be able to roll an area on the surface 101a of the base material 101 that is 10 mm or more away from the boundary 103 between the welded portion 102 and the base material 101 and within 25 mm of the boundary 103 along a direction parallel to the longitudinal direction of the welded portion 102. The reduction rate during rolling can be adjusted within a range of at least 0.5 to 2.0%.

In the correction method of this embodiment, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the base material 101 is rolled along the longitudinal direction of the welded portion 102, thereby correcting the welding deformation. Rolling is performed simultaneously on each of a pair of base materials 101 on both sides in the width direction of the welded portion 102. Here, the area in which the rolling rolls 2 are in contact is within a region R that is 10 mm or more away from the boundary 103 between the welded portion 102 and the base material 101 on the surface 101a of the base material 101, and within 25 mm of the boundary 103. The rolling conditions in the correction method are described below.

The base materials 101 to be rolled are a pair of base materials 101 on both sides of the welded portion 102 in the width direction. If rolling is performed only on the base materials 101 on one side of the welded portion 102 in the width direction, only one of the base materials 101 will stretch along the longitudinal direction of the welded portion 102, and not only will the welding deformation not be corrected, but the welded portion 102, which is formed in a straight line, will be curved. Therefore, it is preferable to simultaneously roll the base materials 101 on both sides of the welded portion 102 in the width direction.

As shown in FIG. 2, it is preferable to use a crown roll in which the roll surface 2b bulges in an arc shape as the rolling roll 2. By using a crown roll as the rolling roll 2, the contact area with the base material 101 is reduced, making it possible to roll down efficiently, and the indentations made by the rolling roll 2 are less noticeable. Furthermore, even if the base material 101 is tilted relative to the rolling roll 2 during rolling, there is no risk of plastic deformation of the base material 101. It is preferable that the crown height of the rolling roll 2 is 100 μm or more.

The area in which the rolling roll 2 comes into contact is, as shown in FIG. 2, within a region that is 10 mm or more away from the boundary 103 between the welded portion 102 and the base material 101 on the surface 101a of the base material 101 and within 25 mm of the boundary 103. It is preferable that the boundary 103 between the welded portion 102 and the base material 101 is the boundary between the weld metal of the welded portion 102 and the base material.

When buckling deformation occurs in the welded joint 100, in the region R that is 10 mm or more away from the boundary 103 and within 25 mm from the boundary 103, the difference between the longitudinal residual stress of the welded portion 102 on the surface 101a side of the base material 101 and the longitudinal residual stress of the welded portion 102 on the back surface 101b side opposite the surface 101a becomes large in each of the pair of base materials 101 of the welded joint 100. It is presumed that the buckling deformation occurs due to this difference in residual stress. Therefore, in this embodiment, the base material 101 is sandwiched between the rolling rolls 2 from both sides in the thickness direction of the base material 101 and lightly pressed down in this region R, thereby reducing the difference in residual stress between the surface 101a and the back surface 101b of the base material 101. This reduces the buckling deformation. The range in which the rolling rolls 2 are in contact is more preferably within a region that is 12 mm or more away from the boundary 103 and within 17 mm from the boundary 103.

When performing light reduction, the reduction ratio is in the range of 0.5 to 2.0%. By setting the reduction ratio to 0.5% or more, the difference in residual stress between the front surface 101a and the back surface 101b of the base material 101 can be sufficiently reduced, and buckling deformation can be mitigated. In addition, by setting the reduction ratio to 2.0% or less, the occurrence of cracks near the welded portion 102 can be prevented.

Figure 3 shows the welded joint 110 after correction. In the welded joint 100 shown in Figure 3, the curvature of the base material 101 along the longitudinal direction of the welded portion 102 has been eliminated, and the buckling deformation has been corrected.

Figure 4 shows a distribution diagram of residual stress on the surface 101a side of the butt welded joint 100 before correction, and Figure 5 shows a distribution diagram of residual stress on the back surface 101b side. As shown in Figure 4, on the surface 101a side of the welded joint 100, tensile residual stress occurs along the longitudinal direction of the welded part 102 near the welded part 102. On the other hand, as shown in Figure 5, on the back surface 101b side of the welded joint 100, compressive residual stress occurs along the longitudinal direction of the welded part 102 near the welded part 102. In the region R that is 10 mm or more away from the boundary 103 between the welded part 102 and the base material 101 and within 25 mm from the boundary 103, the difference between the residual stress on the surface 101a side and the residual stress on the back surface side is large, and the difference in residual stress is particularly large in the region that is 12 mm or more away from the boundary and within 17 mm from the boundary 103. In this embodiment, by performing rolling using the rolling roll 2 on the area where the difference in residual stress between the front surface 101a and the back surface 101b is large, the difference in residual stress between the front surface 101a and the back surface 101b becomes smaller, and buckling deformation can be eliminated.

As described above, according to this embodiment, the buckling deformation in the butt welded joint 100 can be corrected by rolling the region R 10 to 25 mm away from the boundary 103 between the welded portion 102 and the base material 101 from both sides in the thickness direction of the base material 101 using the rolling rolls 2. Furthermore, the correction method of this embodiment can perform sufficient correction compared to the conventional correction method using roll pressure. Furthermore, since this embodiment does not require heating the base material 101, it can be suitably applied to the butt welded joint 100 made of stainless steel plate. Furthermore, since this embodiment does not involve hammering the base material 101, no skill is required from the worker, and it can also handle welding deformations of complex shapes.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings.
An example of a welded joint that can be subjected to the correction method of this embodiment is a welded joint 200 as shown in Fig. 6. The welded joint 200 shown in Fig. 6 includes a pair of base materials 101 made of stainless steel plates and a welded portion 102. The welded joint 200 shown in Fig. 6 has angular deformation as well as buckling deformation after butt welding. The buckling deformation is defined as a welding deformation in which the base material 101 is curved along the longitudinal direction of the welded portion 102 so as to protrude toward the welding torch. The angular deformation is defined as a welding deformation in which the welded portion 102 is deformed into a V-shape with the welded portion 102 as a valley line.

Next, the straightening method of this embodiment will be described. Figures 7 and 8 are diagrams for explaining the straightening device and the straightening method of this embodiment. In the straightening method of this embodiment, as shown in Figures 7 and 8, a straightening device 10 is used that is equipped with a rolling roll 2 similar to that of the first embodiment and a straightening roll 3 that presses the welded portion 102. The straightening roll 3 that presses the welded portion 102 is configured to press the welded portion 102 along the longitudinal direction of the welded portion 102. The straightening roll 3 is a crown roll whose roll surface 3a bulges in an arc shape. In the straightening device 10, the direction of the arrow X is the transport direction of the welded joint 200, as shown in Figure 8.

In addition, when the welded joint 200 is long in the weld line direction, the straightening device 10 may be provided with a support roll 5 that supports the welded joint 200 from the underside in front of and/or behind the conveying direction X (weld line direction) of the welded joint of the rolling roll 2, as shown in FIG. 8.

As shown in FIG. 8, the position of the straightening roll 3 is preferably aligned with the rolling roll 2 when viewed from a direction perpendicular to the conveying direction X of the welded joint 200. The positions of the rolling roll 2 and the straightening roll 3 are based on the contact positions where the rolls 2 and 3 contact the base material 101, and the contact positions may be aligned at the same position when viewed from a direction perpendicular to the conveying direction X of the welded joint 200. By making the position of the straightening roll 3 the same as the position of the rolling roll 2, the straightening of the angular deformation by the straightening roll 3 can be performed at the same time as the straightening of the buckling deformation by the rolling roll 2. The position of the straightening roll 3 does not need to be exactly the same as the rolling roll 2. For example, the position of the straightening roll 3 may be shifted within a range of 10 mm from the position of the rolling roll 2.

The correction method of this embodiment is performed in the same manner as in the first embodiment. That is, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the welding deformation is corrected by rolling along the longitudinal direction of the welded portion 102. Rolling is performed simultaneously on each of a pair of base materials 101 on both sides in the width direction of the welded portion 102. The area in which the rolling rolls 2 are in contact is within a region R that is 10 mm or more away from the boundary 103 between the welded portion 102 and the base material 101 on the surface 101a of the base material 101, and within 25 mm of the boundary 103. The reduction rate by the rolling rolls 2 is in the range of 0.5 to 2.0%.

In addition, in the correction method of this embodiment, during rolling by the rolling roll 2, the distance M between the end face 2a on the boundary side of the rolling roll 2 and the boundary 103 is maintained at a distance equal to or greater than the thickness of the base material.

Furthermore, in this embodiment, as shown in Figs. 7 and 8, the straightening roll 3 presses the welded portion 102 from the side where the welded portion 102 protrudes due to angular deformation. Because the base material 101 on both sides of the welded portion 102 is constrained by the rolling roll 2, pressing the welded portion 102 with the straightening roll 3 generates a reverse bending deformation against the angular deformation. In order to generate a reverse bending deformation, the height of the straightening roll 3 may be set to the same height as the lower rolling roll 2, or to a height equal to or greater than the height of the lower rolling roll 2 and equal to or less than the height of the lower rolling roll 2 + 2 mm. In this way, by generating a reverse bending deformation against the angular deformation in the welded joint 200, it is possible to eliminate the angular deformation.

Furthermore, if the rolling roll 2 is too close to the welded portion 102, when the straightening roll 3 reversely bends the welded joint 200 and warps the base material 101 upward, there is a risk that the warped base material 101 may come into contact with the end face 2a of the upper rolling roll 2 on the opposite side of the straightening roll 3 across the welded joint 200. Therefore, when using the straightening roll 3 as in this embodiment, the distance M between the end face 2a on the boundary side of the rolling roll 2 and the boundary 103 is set to at least the thickness of the base material 101.

Figure 9 shows the welded joint 210 after correction. In the welded joint 210 shown in Figure 9, the curvature of the base material 101 along the longitudinal direction of the welded portion 102 has been eliminated, and the buckling deformation has been corrected. In addition, the angular distortion has also been eliminated.

As described above, according to this embodiment, the welded joint 200 being rolled by the rolling roll 2 is pressed by the straightening roll 3 from the side where the welded part 102 protrudes due to angular distortion, so that the angular distortion can be corrected simultaneously with the buckling deformation. In addition, by leaving a distance M between the end face 2a of the rolling roll 2 on the boundary side and the boundary 103 that is equal to or greater than the thickness of the base material 101, the base material 101 of the welded joint 200 pressed by the straightening roll 3 can be prevented from coming into contact with the end face 2a of the rolling roll 2 on the opposite side of the straightening roll 3 across the welded joint 200.

In addition, the correction method of this embodiment has been described as a case in which a welded joint 200 in which buckling deformation and angular distortion have occurred is corrected, but the object of correction in this embodiment is not particularly limited, and a welded joint in which only angular distortion has occurred may be the object of correction.

Third Embodiment
Next, a third embodiment of the present invention will be described with reference to the drawings. The object of correction in this embodiment is, for example, a welded joint 200 in which buckling deformation and angular distortion occur, as in the second embodiment.

In this embodiment, a straightening jig 4 is used instead of the straightening roll 3 in the second embodiment. Figures 10 and 11 are front and side views, respectively, for explaining the straightening device and the straightening method of this embodiment. The straightening device 20 shown in Figures 10 and 11 is provided with a straightening jig 4 that presses the welded portion 102 from the side where the welded portion 102 protrudes due to angular deformation. The straightening jig 4 is configured to press the welded portion 102 from the back surface 101b side. Also, as shown in Figure 10, the tip surface 4a of the straightening jig 4 when viewed from the transport direction of the welded joint is a curved surface that bulges in an arc shape. Also, as shown in Figure 11, the tip surface 4a of the straightening jig 4 when viewed from the side of the transport direction of the welded joint is a curved surface that protrudes upward in an arc shape. This makes it possible to press the welded portion 102 while sliding the straightening jig 4 and the welded portion 102 relative to each other. A lubricant or the like may be applied between the correction jig 4 and the welded portion 102 to improve sliding properties.

The correction method of this embodiment is performed in the same manner as in the first embodiment. That is, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the welded joint 200 is conveyed in the conveying direction X while being rolled along the longitudinal direction of the welded portion 102, thereby correcting the welding deformation. Rolling is performed on each of the pair of base materials 101 on both sides in the width direction of the welded portion 102. The area in which the rolling rolls 2 are in contact is within a region R that is 10 mm or more away from the boundary 103 between the welded portion 102 and the base material 101 on the surface 101a of the base material 101, and is within 25 mm from the boundary 103. During rolling by the rolling rolls 2, the distance between the end face 2a on the boundary side of the rolling roll 2 and the boundary 103 is kept at a distance equal to or greater than the thickness of the base material 101. The reduction rate by the rolling rolls 2 is in the range of 0.5 to 2.0%.

Furthermore, in this embodiment, as shown in Figs. 10 and 11, the welded portion 102 is pressed by the correction jig 4 from the side where the welded portion 102 protrudes due to angular distortion, while being rolled by the rolling roll 2. Since the base material 101 on both sides of the welded portion 102 is constrained by the rolling roll 2, pressing the welded portion 102 with the correction jig 4 causes a reverse bending deformation in relation to the angular distortion. In order to cause a reverse bending deformation, the height of the correction jig 4 is set to the same height as the lower rolling roll 2, or to a height equal to or greater than the height of the lower rolling roll 2 and equal to or less than the height of the lower rolling roll 2 + 2 mm. In this way, by causing a reverse bending deformation in relation to the angular distortion in the welded joint 200, it is possible to eliminate the angular distortion.

After correction, the welded joint will have buckling and angular distortion corrected.

As described above, according to this embodiment, the welded joint 200 being rolled by the rolling roll 2 is pressed against the welded portion 102 by the correction tool 4 from the side where the welded portion 102 protrudes due to angular distortion, so that the angular distortion can be corrected simultaneously with the buckling deformation. In addition, by leaving a distance M between the end face 2a of the rolling roll 2 on the boundary side and the boundary 103 that is equal to or greater than the thickness of the base material 101, the base material 101 of the welded joint 200 pressed against the correction roll 3 can be prevented from coming into contact with the end face 2a of the rolling roll 2 on the opposite side of the correction roll 3 across the welded joint 200.

The correction tool 4 according to this embodiment is not limited to the one shown in Figs. 10 and 11. For example, as shown in Fig. 12, a correction tool 44 having a length along the longitudinal direction of the welded portion 102 longer than the correction tool 4 shown in Figs. 10 and 11 may be used, the welded joint 200 may be placed on the correction tool 44, and the welded joint 102 may be pressed by the correction tool 44 while the roll roll 2 is moved in the direction of arrow Y relative to the correction tool 44 and the welded joint 200 to roll them, thereby generating a reverse bending deformation in relation to the angular deformation.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to the drawings. An example of a correction target of this embodiment is a welded joint 300 as shown in Fig. 13. The welded joint 300 shown in Fig. 13 has angular distortion as well as buckling distortion after butt welding, similar to the welded joint shown in Fig. 6. The welded joint 300 shown in Fig. 13 has a larger amount of buckling distortion than the welded joint 200 shown in Fig. 6.

Figures 14 to 17 are diagrams illustrating the straightening device and straightening method of this embodiment. In the straightening method of this embodiment, as shown in Figures 14 and 16, a straightening device 20 similar to that of the second embodiment is used. This straightening device 20 is equipped with a rolling roll 2 and a straightening roll 3 that presses the welded portion 102. The straightening roll 3 that presses the welded portion 102 is configured to press the welded portion along the longitudinal direction of the welded portion 102. In addition, the straightening roll 3 is a crown roll with a roll surface 3a that bulges in an arc shape.

In the correction method of this embodiment, the first and second steps are performed in sequence. In the first step, as in the first embodiment, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the welding deformation is corrected by rolling along the longitudinal direction of the welded portion 102. In this first step, correction by the correction roll 3 is not performed. Next, in the second step, as in the second embodiment, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the welded portion 102 is rolled along the longitudinal direction of the welded portion 102, and the welded portion 102 is pressed by the correction roll 3, thereby correcting the welding deformation.

It is preferable that the reduction rate of the rolling roll 2 in the first step is in the range of 0.5 to 2.0%, and the reduction rate of the rolling roll 2 in the second step is in the range of 0.1 to 2.0%.

That is, in the first step, as shown in FIG. 14, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the base material 101 is rolled along the longitudinal direction of the welded portion 102 to correct the welding deformation. The pair of base materials 101 on both sides in the width direction of the welded portion 102 are rolled simultaneously. The area in which the rolling rolls 2 are in contact is an area that is 10 mm or more away from the boundary 103 between the welded portion 102 and the base material 101, and is within 25 mm of the boundary 103. During rolling by the rolling rolls 2, the distance M between the end face 2a on the boundary side of the rolling roll 2 and the boundary 103 is kept at a distance equal to or greater than the thickness of the base material. In the first step, the correction roll 3 is kept retracted below the welded portion 102.

Figure 15 shows the welded joint 310 after the first step. As shown in Figure 15, the buckling deformation of the welded joint 310 after the first step has been completely or incompletely corrected by rolling with the reduction rolls. In addition, the angular distortion has been corrected to some extent, but has not yet been completely corrected.

Next, in the second step, as shown in FIG. 16, the rolling rolls 2 are brought into contact with the base material 101 from both sides in the thickness direction of the base material 101, and the base material 101 is rolled along the longitudinal direction of the welded portion 102, while the straightening roll 3 presses the welded portion 102 from the side where the welded portion 102 protrudes due to angular deformation. The height of the straightening roll 3 may be the same as in the second embodiment. The rolling conditions by the rolling roll 2 may be the same as those in the first step, or may be changed from those in the first step. For example, the reduction rate in the second step may be lower than that in the first step within a range of 0.1 to 2.0%. The contact position of the rolling roll 2 in the second step may be at a position different from the contact position in the first step, within a region 10 mm or more away from the boundary 203 and within 25 mm from the boundary 203.

Figure 17 shows the welded joint 320 after the second process. As shown in Figure 17, the buckling deformation of the welded joint 320 after the second process has been almost completely corrected by rolling with the rolling roll 2. In addition, the angular distortion has also been almost completely corrected.

The straightening method of this embodiment can reduce the amount of buckling deformation by correcting the buckling deformation in the first step, even when the amount of buckling deformation is particularly large and the straightening roll 3 cannot sufficiently correct the angular distortion, so that the angular distortion can be reliably corrected using the straightening roll 3 in the subsequent second step.

As described above, according to the correction method of this embodiment, for a butt welded joint 300 in which both buckling and angular distortion have occurred and the amount of buckling distortion has increased, the buckling distortion is corrected by performing a first process of rolling the above-mentioned region R of the base material 101 with the rolling roll 2, and then performing a second process of rolling the above-mentioned region R of the base material 101 with the rolling roll 2 and pressing the welded portion 102 with the correction roll 3, thereby correcting the buckling distortion and angular distortion and more reliably correcting the welding distortion.

In this embodiment, the straightening method using the straightening device 20 equipped with the straightening roll 3 has been described, but the present invention is not limited to this, and the straightening method of this embodiment may be performed using a straightening device 30 equipped with straightening jigs 4 and 44 as in the third embodiment.

1, 10, 20, 30...straightening device, 2...rolling roll, 2a...end surface, 3...straightening roll, 4, 44...straightening jig, 100, 200, 300...butt weld joint, 101...base material, 101a...surface, 102...weld, 103 boundary, R...area.

Claims (9)

A method for correcting a butt welded joint having a pair of base materials made of stainless steel plates and a welded portion, comprising the steps of:
For each of the pair of base metals, a rolling roll is brought into contact with both sides of the base metal in a thickness direction within a region on the surface of the base metal that is 10 mm or more away from a boundary between the welded portion and the base metal and within 25 mm of the boundary, and the base metal is rolled along the longitudinal direction of the welded portion ;
A method for correcting a butt welded joint , in which a crown roll having a roll surface bulging in an arc shape is used as the rolling roll . A method for correcting a butt welded joint having a pair of base materials made of stainless steel plates and a welded portion, comprising the steps of:
For each of the pair of base metals, a rolling roll is brought into contact with both sides of the base metal in a thickness direction within a region on the surface of the base metal that is 10 mm or more away from a boundary between the welded portion and the base metal and within 25 mm of the boundary, and the base metal is rolled along the longitudinal direction of the welded portion;
The welded portion is pressed by a straightening roll or a straightening jig from the side where the welded portion protrudes due to angular distortion against the butt welded joint being rolled by the rolling roll,
a distance between the boundary end face of the rolling roll and the boundary is set to a dimension equal to or greater than a plate thickness of the base material during the rolling . The method for correcting a butt welded joint according to claim 1 or 2, wherein a reduction ratio in rolling the base material by the reduction rolls is 0.5 to 2.0%. A method for correcting a butt welded joint having a pair of base materials made of stainless steel plates and a welded portion, comprising the steps of:
a first step of rolling the base metal along the longitudinal direction of the weld by contacting a rolling roll with both sides of the base metal in a thickness direction of the base metal in a region of the base metal surface that is 10 mm or more away from a boundary between the weld and the base metal and within 25 mm of the boundary;
a second step of rolling the base material along the longitudinal direction of the welded portion by the rolling rolls while contacting the region with rolling rolls from both sides in the plate thickness direction of the base material and pressing the welded portion with a straightening roll or a straightening tool from the side where the welded portion protrudes due to angular deformation;
Equipped with
A method for correcting a butt welded joint, wherein during the rolling in the first step and the second step, a distance between the end face of the rolling roll on the boundary side and the boundary is set to be equal to or greater than a dimension corresponding to a plate thickness of the base material. In the rolling of the base material by the rolling rolls in the first step, a rolling reduction is set to 0.5 to 2.0%,
The method for correcting a butt welded joint according to claim 4, wherein the rolling reduction rate in the rolling of the base material by the rolling rolls in the second step is 0.1 to 2.0%. 6. The method for correcting a butt welded joint according to claim 2 , wherein a crown roll having a roll surface bulging in an arc shape is used as the reduction roll. A device for correcting a butt welded joint having a pair of base materials and a welded portion made of stainless steel plates, comprising:
For each of the pair of base metals, a rolling roll is provided that contacts the base metal from both sides in a plate thickness direction within a region that is 10 mm or more away from a boundary between the welded portion and the base metal on the surface of the base metal and within 25 mm from the boundary, and rolls the welded portion along a longitudinal direction ,
1 is a schematic diagram showing a straightening apparatus for a butt welded joint according to the first embodiment of the present invention ; A device for correcting a butt welded joint having a pair of base materials and a welded portion made of stainless steel plates, comprising:
For each of the pair of base metals, a rolling roll is provided that contacts the base metal from both sides in a plate thickness direction within a region that is 10 mm or more away from a boundary between the welded portion and the base metal on the surface of the base metal and within 25 mm from the boundary, and rolls the welded portion along a longitudinal direction,
A straightening device for a butt welded joint , comprising a straightening roll or a straightening tool that presses the welded portion from the side where the welded portion protrudes due to angular distortion against the welded joint being rolled by the rolling rolls. 9. The apparatus for straightening a butt welded joint according to claim 8 , wherein the reduction roll is a crown roll having a roll surface bulging in an arc shape.

Images