Runoff plate and welding method using runoff plate

Abstract

To reduce work hours for removing a run-off plate 1 significantly.SOLUTION: A run-off plate 1 is fixed to a base material end part 100E of a welding joint 100J of a base material 100 when the base material 100 (101 and 102) is welded. Further, the run-off plate 1 is used to prevent a welding end part of joint work, in which the base material 100 is welded, from remaining in the base material 100 and includes: a projection part 10 which is placed in contact with the base material end 100E; a body part 20 which is disposed around the projection part 10 and fixed to the base material 100 in a state that the projection part 10 contacts with the base material end 100E; and a connection part 30 which connects the projection part 10 with the body part 20 and is burned through by heat being applied thereto during the joint work.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a runoff plate and a welding method using the runoff plate. [Background technology]

[0002] It has long been known that craters or burn-through occur at the end of a weld, and in order to prevent these defects from occurring in the base metal being welded, a welding process using a run-off plate that sets the end of the weld on the outside of the joint is known (Non-Patent Document 1). Note that, in this specification, "crater" refers to a crater defined in JIS Z3001-7:2018 No. 73146 (ISO / TR25901-4:2016), and "burn-through" refers to burn-through defined in JIS Z3001-4:2013 No. 47010 (ISO6520-1:1998 No. 510). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Technology for preventing end cracks in one-sided submerged arc welding," by Yamato Yokota, KOBELCO Publishing, October 2018 issue Summary of the Invention [Problem to be solved by the invention]

[0004] However, because runoff plates are welded to the base material, the removal process takes time. Runoff plates are typically removed by grinding with a grinder, and the larger the volume of the joint between the runoff plate and the base material, the longer the removal process takes. Another method involves bending the runoff plate, but this can create notches in the base material when the runoff plate is removed, which can result in lower product quality. In other words, while welding using runoff plates can eliminate weld defects that occur at the weld end, it has the drawback of requiring a lot of time and effort to remove the runoff plate. However, because a certain size is required for the runoff plate to be fixed to the base material before welding, there is a limit to how small the runoff plate can be. [Means for solving the problem]

[0005] One aspect of the present invention is a runoff plate that is fixed to the base metal end of a weld joint of a base metal when welding the base metal, so that the end of the weld from the joining operation of welding the base metal does not remain on the base metal, and it comprises a protrusion that abuts against the base metal end, a main body that is arranged around the protrusion and is fixed to the base metal with the protrusion abutting against the base metal end, and a connection that connects the protrusion and main body and melts away when heat generated during the joining operation is applied.

[0006] According to one aspect of the present invention, a runoff plate includes a protrusion that abuts against the end of a base metal in a welded joint of the base metal, thereby extending the joining operation of the base metal from the end of the base metal to the protrusion. This prevents defects that occur at the end of a weld from occurring in the base metal. The protrusion is arranged around the protrusion and is fixed to the base metal with the protrusion abutting the end of the base metal, thereby maintaining the protrusion in a state of abutting against the end of the base metal. The protrusion and the main body are connected to each other by a connecting portion that melts away when heat generated during the joining operation is applied, thereby extending the joining operation from the end of the base metal to the protrusion, melting away the connecting portion and fusing the main body away from the protrusion. This allows only the protrusion to be joined to the base metal.

[0007] One aspect of the present invention is a welding method using a runoff plate comprising: a protrusion that abuts against the base metal end of a welded joint in the base metal; a main body that is arranged around the protrusion and fixed to the base metal with the protrusion abutting against the base metal end; and a connection that connects the protrusion and main body and melts down when heat generated during the joining operation is applied; the protrusion abuts against the base metal end of the welded joint in the base metal, the main body is fixed to the base metal, the joining operation is extended from the base metal end to the protrusion to melt down the connection, and the protrusion welded to the base metal is removed after the joining operation.

[0008] According to a welding method using a runoff plate, which is one aspect of the present invention, the protrusion is brought into contact with the end of the base material of the weld joint and the main body is fixed to the base material, thereby maintaining the protrusion in contact with the end of the base material. This allows the end of the weld in the joining operation of the base material to be extended from the end of the base material to the protrusion, preventing defects that occur at the end of the weld from occurring in the base material. By extending the joining operation from the end of the base material to the protrusion and melting off the connection, the main body can be fused from the protrusion. This leaves only the protrusion joined to the base material. [Effects of the Invention]

[0009] According to one aspect of the present invention, the number of steps required to remove the runoff plate can be significantly reduced. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a runoff plate according to this embodiment. [Figure 2A] FIG. 2A is a diagram showing a state in which the runoff plate according to this embodiment is fixed to a base material, and a state in which the joining operation is extended from the end of the base material to the protrusion. [Figure 2B] FIG. 2B is a view showing a state in which the main body portion has been fused after the joining operation of the runoff plate according to this embodiment. [Figure 3] FIG. 3 is a diagram showing the dimensions and positions of various portions of the runoff plate according to this embodiment. [Figure 4] FIG. 4 is a diagram showing a melt-run test for determining the dimensions of the protrusions and connection portions of the runoff plate according to this embodiment. [Figure 5A] FIG. 5A is a top view showing an example of a jig for fixing the runoff plate according to the present embodiment, and is a diagram showing an example of a method for determining the dimensions of the main body portion. [Figure 5B] FIG. 5B is a side view showing an example of a jig for fixing the runoff plate according to the present embodiment, and is a diagram showing an example of a method for determining the dimensions of the main body portion. [Figure 6A] FIG. 6A shows a test plate used in testing to determine the appropriate dimensions of the connection. [Figure 6B] FIG. 6B is a diagram showing the test content for determining the dimension at which the connection portion burns through. [Figure 7A] FIG. 7A is a diagram showing test results of the connection portion (part 1). [Figure 7B] FIG. 7B is a diagram showing test results of the connection portion (part 2). [Figure 8A] FIG. 8A is a diagram showing the bead width obtained in the melt-run test. [Figure 8B] FIG. 8B is a diagram showing the test results of the connection portion (part 3). [Figure 8C] FIG. 8C is a diagram showing test results of the connection portion (part 4). [Figure 9] Figure 9 shows the crater length obtained in the melt-run test. [Figure 10A] FIG. 10A is a diagram showing test results of the protrusions (part 1). [Figure 10B] FIG. 10B is a diagram showing the test results of the protrusions (part 2). [Figure 10C] FIG. 10C shows the test results of the protrusions (part 3). [Figure 10D] FIG. 10D shows the test results of the protrusions (part 4). [Figure 11] FIG. 11 is a diagram showing another example of the planar shape of the protrusion. [Figure 12]FIG. 12 is a diagram illustrating types of weld joints to which the runoff plate according to this embodiment can be applied. [Figure 13A] FIG. 13A is a diagram (part 1) that schematically illustrates a welding method using a runoff plate according to this embodiment. [Figure 13B] FIG. 13B is a diagram (part 2) that schematically illustrates a welding method using a runoff plate according to this embodiment. [Figure 13C] FIG. 13C is a diagram (part 3) that schematically illustrates a welding method using a runoff plate according to this embodiment. [Figure 13D] FIG. 13D is a diagram (part 4) that schematically illustrates a welding method using a runoff plate according to this embodiment. [Figure 13E] FIG. 13E is a diagram (part 5) that schematically illustrates a welding method using a runoff plate according to this embodiment. [Figure 14] FIG. 14 is a flowchart showing a welding method using a runoff plate according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The embodiments will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0012] [Runoff plate configuration] The configuration of a runoff plate 1 according to this embodiment will be described with reference to Figures 1 to 2B. The runoff plate 1 according to this embodiment is a plate-like member that is fixed to a base metal end 100E of a weld joint 100J of base metal 100 when joining base metals 101 and 102, and that extends the weld termination portion of the joining operation of the base metals 100 outward from the base metal end 100E. In this embodiment, for example, the base metals 101 and 102 are joined by laser welding, but arc welding may also be used.

[0013] FIG. 1 is a diagram showing an example of the configuration of a runoff plate according to this embodiment. FIG. 2A is a diagram showing a state in which the runoff plate according to this embodiment is fixed to a base material and a state in which the joining operation extends from the end of the base material to the protrusion. FIG. 2B is a diagram showing a state in which the main body of the runoff plate according to this embodiment has been melted after the joining operation. Note that the "joining operation" refers to the operation of melting and joining the base material 100. For example, in the case of laser welding, the joining operation corresponds to the operation of irradiating a laser onto the weld joint 100J.

[0014] The runoff plate 1 comprises a protrusion 10 that abuts against the base material end 100E of the weld joint 100J of the base material 100, a main body 20 that is arranged around the protrusion 10 and fixed to the base material 100 with the protrusion 10 abutting against the base material end 100E, and a connection part 30 that connects the protrusion 10 and the main body 20 and melts down when heat generated during the joining operation is applied.

[0015] The connection portion 30 is a heat conduction path between the protrusion 10 and the main body 20. The connection portion 30 is located at the end of the weld during the joining operation and is sized to melt away during the joining operation. The connection portion 30 may connect the protrusion 10 and the main body 20 at a position on an extension line of the weld joint 100J.

[0016] The protrusion 10 is thermally insulated from the main body by a thermal insulating element, except for the connection portion 30. In this embodiment, a slit 40 is provided as the thermal insulating element. Note that the thermal insulating element is not limited to the slit 40. For example, the thermal insulating element may be a material with low thermal conductivity relative to the protrusion 10 and the main body 20, or a material with low thermal conductivity may be arranged around the protrusion 10, except for the connection portion 30.

[0017] The runoff plate 1 may be cut from a single sheet metal using, for example, a laser processing machine. The material of the runoff plate 1 is the same as that of the base material 100 when it is not permitted to produce an alloy different from that of the base material at the interface between the runoff plate 1 and the base material 100; however, except in such cases, the material of the runoff plate 1 is not limited. The material of the runoff plate 1 may be, for example, cold-rolled steel plate (SPCC: Steel Plate Cold Commercial). The dimensions of each part of the runoff plate 1 are determined based on a melt-run test, which will be described later, to satisfy the requirements for the runoff plate 1 according to this embodiment.

[0018] Next, with reference to FIGS. 2A and 2B , a description will be given of a joining operation using the runoff plate 1 and the state of the runoff plate 1 after the joining operation. As shown in FIG. 2A , the joining operation is performed along the weld joint 100J toward the base metal end 100E and then extends from the base metal end 100E to the protrusion 10 of the runoff plate 1. More specifically, the joining operation is extended to a position where the weld end overlaps the connection portion 30. For example, laser irradiation (an example of a welding operation) may be terminated at the connection portion 30. This allows the connection portion 30 to melt through due to the heat generated during the joining operation, thereby melting the main body portion 20 away from the protrusion 10. Furthermore, defects caused by the joining operation occur in the protrusion 10. Therefore, the protrusion 10 can prevent defects from occurring in the base metal 100. The defect refers to a crater C or burn-through that occurs at the weld end.

[0019] As shown in FIG. 2B , after the joining operation, the runoff plate 1 has the main body 20 (not shown) separated from the protrusion 10, and only the protrusion 10 remains joined to the base material 100. This reduces the size of the protrusion 10 that remains joined to the base material 100 compared to conventional runoff plates, thereby reducing the amount of work required for removal. The figure shows an example in which the joining operation is extended to a position where the weld end overlaps the connection portion 30. However, as long as the connection portion 30 melts down and the main body 20 is fused away from the protrusion 10 after the joining operation, the joining operation may be extended to a position where the weld end overlaps the main body 20. In other words, the laser irradiation (an example of the joining operation) may be extended to the main body 20, passing through the protrusion 10 and the connection portion 30.

[0020] As described above, the protrusions 10 are intended to prevent defects from occurring in the base material 100 and must dissipate heat conducted during the joining process as efficiently as possible, similar to the base material 100. However, it is desirable for the protrusions 10 to be as small as possible to reduce the labor required for removal after the joining process. The connection portions 30 may melt away due to the heat generated during the joining process, causing the main body portion 20 to melt away from the protrusions 10. Even if they do not melt away, they can be easily broken off and removed manually. Meanwhile, it is desirable for the main body portion 20 to have sufficient size and rigidity to ensure ease of use during setup operations, such as when fastening the main body portion 20, and for the connection portions 30 to be rigid enough to withstand deformation even when pressed against the base material by a jig or the like. To satisfy these conditions, it is desirable to appropriately set the dimensions of each part of the runoff plate 1.

[0021] A method for setting the dimensions of each part of the runoff plate 1 will be described below with reference to FIGS. 3 to 5B. FIG. 3 is a diagram showing the position of each dimension of the runoff plate according to this embodiment. FIG. 4 is a diagram showing a melt-run test for determining the dimensions of the protrusions and connection parts of the runoff plate according to this embodiment. FIG. 5A is a top view of a jig for fixing the runoff plate according to this embodiment, showing an example of a method for determining the dimensions of the main body. FIG. 5B is a side view of a jig for fixing the runoff plate according to this embodiment, showing an example of a method for determining the dimensions of the main body.

[0022] The length 10L and width 10W of the protrusion 10 and the length 30L and width 30W of the connection portion 30 shown in Fig. 3 are determined based on the results of a melt-run test shown in Fig. 4. The length 20L and width 20W of the main body 20 may be determined based on the jig 50 that fixes the main body 20. Note that the length is the dimension of the weld joint 100J in the longitudinal direction shown in Fig. 2A, and the width is the dimension of the weld joint 100J in the width direction.

[0023] The melt-run test measures the width of the bead and the length of the crater created during the welding process by performing a similar welding operation to that performed when welding a base metal 100 to a metal sheet of the same thickness and material as the runoff plate 1. In the melt-run test shown in Figure 4, a metal sheet SM of the same thickness and material as the runoff plate 1 is welded from position WS to position WE, and the width BW of the bead B and the length CL of the crater C created during the welding process are measured. Bead B is a raised portion of the weld metal WM created during the welding process, and crater C is a depression created at the end of bead B (position WE) during the welding process. The state before bead B is formed, i.e., the metal puddle created by the base metal melting due to the heat generated during the welding process, is called the molten pool. The method for measuring the width BW of bead B and the length CL of crater C will be described later with reference to Figures 8A and 9.

[0024] The "melt run" in the melt run test refers to the melt run defined in JIS Z 3001-1:2018 No. 11707 (ISO / TR 25901-1:2016). The "bead" refers to the bead defined in JIS Z 3001-7 No. 73102 (ISO / TR 25901-4). The "crater" refers to the crater defined in JIS Z 3001-7 No. 73146 (ISO / TR 25901-4). The "molten pool" refers to the molten pool defined in JIS Z 3001-7:2018 No. 73143 (ISO / TR 25901-4:2016).

[0025] Here, a method for measuring the width BW of a bead B and the length CL of a crater C formed by a melt-run test on a metal sheet of the same thickness and material as the runoff plate 1 will be described with reference to FIGS. 8A and 9. FIG. 8A shows the bead width obtained by the melt-run test. FIG. 9 shows the crater length obtained by the melt-run test. The width BW of a bead B and the length CL of a crater C can be measured, for example, using a digital microscope. Specifically, two parallel lines are superimposed on both ends of the width BW direction of a bead B imaged on a digital microscope screen, and the distance between the parallel lines calculated by the digital microscope function is taken as the width BW of the bead B. The same applies to the length CL of a crater C. Two parallel lines are superimposed on both ends of the length CL direction of a crater C imaged on a digital microscope screen, and the distance between the parallel lines calculated is taken as the length CL of the crater C. Note that the ends of the bead B in the width BW direction are wavy, resulting in variations in the width BW of the bead B. Therefore, in this embodiment, the width BW of bead B is calculated by placing a parallel line at the median between the maximum and minimum widths of one bead formed by the melt run test, and is described as a dimension ( FIG. 8A ), but the method for calculating the width BW of bead B is not limited to this, and any value between the maximum and minimum values ​​of the width BW of bead B may be used. Furthermore, what is simply described as the width BW of bead B may be any value included in the range between the minimum and maximum values ​​of the width BW of bead B.

[0026] The length 30L and width 30W of the connecting portion 30 are determined based on the width BW of the bead B measured by the melt-run test. Specifically, the length 30L of the connecting portion 30 satisfies formula (1), and the width 30W of the connecting portion 30 satisfies formula (2). [Number 1] Length of connection = width of bead × 0.3 (1) [Number 2] Connection width = Bead width × 0.3 (2)

[0027] By satisfying formulas (1) and (2), the connecting portion 30 has the rigidity to hold the protruding portion 10 without deforming when the main body portion 20 is fixed. Furthermore, the connecting portion 30 melts away when heat generated during the joining operation is applied. Even if the connecting portion 30 does not melt away, the connecting portion 30 can be easily broken off to remove the main body portion 20. Details of formulas (1) and (2) will be described later with reference to FIGS. 6A to 8C.

[0028] The length 10L and width 10W of the protrusion 10 are determined based on the width BW of the bead B and the length CL of the crater C measured by the melt-run test. Specifically, the length 10L of the protrusion 10 satisfies formula (3), and the width 10W of the protrusion 10 satisfies formula (4). [Number 3] Length of protrusion ≥ length of crater (3) [Number 4] Width of protrusion ≧ Width of bead × 3 (4)

[0029] By satisfying formulas (3) and (4), the size of the protrusion 10 (length 10L and width 10W) ​​is such that, when the joint 30 is located at the end of the weld, the molten pool and crater C formed at the protrusion 10 will fit within the protrusion, and the size of the molten pool formed at the protrusion 10 will be the same as or smaller than the size of the molten pool formed in the base material 100. Furthermore, by satisfying formulas (3) and (4), the protrusion 10 will have the minimum dimensions that will not cause the crater C and burn-through that will become defective parts to form in the base material 100. Details of formulas (3) and (4) will be described later with reference to FIGS. 9 to 10D.

[0030] Next, referring to Figures 5A and 5B, an example of a method for determining the length 20L and width 20W of the main body 20 when a jig 50 for fixing the runoff plate 1 is used will be described. Figures 5A and 5B show an example of a jig 50 for fixing the runoff plate 1. The jig 50 includes a base plate 51 and clamp bands 52 (52U and 52L) that are positioned on both sides of the base metal end face, including the base metal end 100E, and parallel to an imaginary line extending from the weld joint 100J, and can press the main body 20. The base metal 100 (101 and 102) and the runoff plate 1 are placed on the base plate 51 and fixed by the clamp bands 52 (52U and 52L). More specifically, with the protrusion 10 abutting the base material end 100E, the main body 20 is fixed to the base material 100 along the longitudinal direction of the weld joint 100J by the weight of the clamp band 52 (52U and 52L).

[0031] Referring to FIG. 5A, the length 20L of the main body 20 is the sum of the lengths of the protrusion 10 and the connecting portion 30 and the length X. The length X is the minimum length necessary to secure the main body 20 without movement until the joining operation moves from the base material 100 to the protrusion 10 and the connecting portion 30 melts through. The width 20W of the main body 20 is the sum of the clamp spacing 52I and the clamping margin H of the two clamps. The clamp spacing 52I is the distance between the two clamp bands 52 (52U and 52L), and the clamping margin H is the width dimension of the weld joint 100J where one clamp band 52 secures the main body 20. The clamp spacing 52I is determined taking into account interference between the clamp bands 52 and the welding head of the laser welding machine. The pressure allowance H of the two clamps is the minimum length required to provide the area required for the main body 20 to be fixed without moving until the joining operation moves from the base material 100 to the protrusion 10 and the connection part 30 melts off.

[0032] When the main body 20 is fixed by the jig 50 using such a fixing method, the length 20L of the main body 20 satisfies the formula (5), and the width 20W of the main body 20 satisfies the formula (6). [Number 5] Length of main body ≥ Length of protrusion + Length of connection + X (5) [Number 6] Width of main body ≧ Clamp spacing + (2 × clamp pressure) (6)

[0033] Next, with reference to Figures 6A to 8C, the test contents and test results when determining equation (1) that is satisfied by length 30L of connection portion 30 and equation (2) that is satisfied by width 30W of connection portion 30 will be described. Figure 6A is a diagram showing a test plate used in a test to determine the appropriate dimensions of the connection portion. Figure 6B is a diagram showing the test contents for determining the dimensions at which the connection portion will burn through. Figures 7A and 7B are diagrams showing the test results of the connection portion. Figures 8B and 8C are diagrams showing the test results of the connection portion.

[0034] As shown in Figure 6A, a slit S was formed in the test plate TP, and a connection portion 30 was formed in the region R surrounded by the dashed line. Tests were conducted while changing the length JL and width JW of the connection portion 30 to determine the appropriate dimensions of the connection portion 30. The dimensions of each portion of the test plate TP are as shown in Figure 6A. The material of the test plate TP is SPCC, and the plate thickness is 1.6 mm.

[0035] First, the inventors conducted a test to determine the dimensions of the connection portion 30 that would maintain the rigidity required to hold the protrusion 10 without deformation during setup operations such as fixing the main body portion 20. In the test, the length JL of the connection portion 30 was fixed at 0.2 mm, and the width JW was varied. The laser welding machine settings were a feed rate of 200 cm / min, a laser power of 2000 W, a spot diameter of 0.72 mm, and an argon (Ar) gas shield of 80 L / min, the same as those used during the welding of the base metal 100. In this case, the width BW of the bead B measured during the welding operation using a melt-run test was 1.83 mm (Figure 8A). In Figure 7A, when the width JW of the connection portion 30 was set to 0.3 mm, an operator or a jig pressed the test plate TP in the direction corresponding to the main body portion 20 toward the base metal. The test plate TP lost its rigidity and underwent plastic deformation due to the moment applied to the connection portion 30 by the pressing force. The portion corresponding to the main body portion 20 is the portion of the test plate TP on the warped side shown in Figure 7A. Next, in Figure 7B, the width JW was changed to 0.5 mm, and the operator or a jig pressed the portion of the test plate TP corresponding to the main body portion 20 in the direction corresponding to the base metal. The test plate TP maintained its shape without deformation. Therefore, the ratio of the width 30W of the connection portion 30, which maintains the rigidity required to hold the protrusion 10, to the width BW (1.83 mm) of the bead B is approximately 0.3, and the width 30W of the connection portion 30 satisfies equation (2) is obtained. The sufficient rigidity of the connection portion 30 before welding depends on the plate thickness of the connection portion 30, so the width BW of the bead B is not directly related. However, the thicker the plate thickness of the base metal 100, the larger the bead width formed. In other words, because there is a positive correlation between the plate thickness and the width BW of the bead B, the width BW of the bead B can be used as a criterion for determining the rigidity of the connection portion 30.

[0036] Next, the inventors conducted a test to determine the melt-through dimension of the connection portion 30 when the joining operation was extended from the base material end 100E to the protrusion 10. As shown in FIG. 6B, in the test, laser irradiation was performed from position WS to position WE on the test plate TP under the same conditions as during the joining operation. Note that in the test, the width JW of the connection portion 30 was fixed at 0.5 mm, a width at which the connection portion 30 had rigidity, and the length JL was varied. In FIG. 8B, when the welding operation was performed with the length JL of the connection portion 30 set to 0.2 mm, the molten metal in and around the connection portion 30 solidified in the slit S without melting through, and the test plate TP did not separate. Next, in FIG. 8B, when the length JL of the connection portion was changed to 0.5 mm and the joining operation was performed, the connection portion 30 melted through and the test plate TP melted. Therefore, the ratio of the width BW (1.83 mm) of bead B to the length 30L of connection portion 30, where the welding end is located at connection portion 30 and connection portion 30 melts down, is approximately 0.3, and the equation (1) that is satisfied by the length 30L of connection portion 30 is obtained.

[0037] Next, with reference to Figures 9 to 10D, we will explain the test content and test results when determining the formula (3) satisfied by the length 10L of the protrusion 10 and the formula (4) satisfied by the width 10W of the protrusion 10. Figure 9 is a diagram showing the crater length obtained in the melt-run test. Figures 10A to 10C are diagrams showing the test results of the protrusion.

[0038] First, the inventors determined the length 10L of the protrusion 10. The protrusion 10 is required to prevent defects from occurring in the base material 100. Therefore, it is desirable that the length 10L of the protrusion 10 is a length that allows the crater C to fit within the protrusion 10 when the welding end is positioned at the connection portion 30. Therefore, the equation (3) that the length 10L of the protrusion 10 satisfies is determined.

[0039] Next, the inventors conducted a test to determine the width 10W of the protrusion 10. The test was conducted by creating a test plate with the same shape as the runoff plate 1. First, the length CL of the crater C was measured by a melt-run test. The settings of the laser processing machine were as described above. As shown in Figure 9, the length CL of the crater C was measured to be 4.5 mm. Therefore, the length 10L of the protrusion 10 was fixed at 5 mm, which satisfies equation (3), and the width 10W of the protrusion 10 was changed.

[0040] FIG. 10A shows the results of welding when the width 10W of the protrusion 10 is 2 mm. In FIG. 10A, the entire protrusion 10 melts, and a portion of the protrusion 10 and the connection portion 30 melt down, leaving a crater C extending into the base material 100. FIG. 10B shows the results of welding when the width 10W of the protrusion 10 is 3 mm, and FIG. 10C shows the results of welding when the width 10W of the protrusion 10 is 4 mm. In FIGS. 10B and 10C, the protrusion 10 is welded to the base material 100 without melting down entirely, but the crater C is excessively large and extends into the base material 100. This is because the heat capacity of the protrusion 10 is insufficient, and the volume of the crater C expands toward the base material 100 more than in the melt-run test results. FIG. 10D shows the results of welding when the width of the protrusion 10 is 5 mm. In FIG. 10D, the crater C does not extend into the base material 100. Therefore, the ratio of the width 10W of the protrusion 10 at which the volume of the crater C does not spread toward the base material 100 to the width BW (1.83 mm) of the bead B is approximately 3, and equation (4) is obtained that satisfies the width 10W of the protrusion 10.

[0041] When the size of the protrusion 10 satisfies Equations (3) and (4), and the joint 30 is located at the end of the weld, the size of the crater C and the size of the molten pool are approximately the same. More specifically, the width of the crater C and the width of the molten pool are approximately the same. Furthermore, the width of the molten pool generated during the melt run test and the width of the molten pool generated during the joining operation of the base metals 100 are approximately the same, and the size of the crater C generated during the melt run test and the size of the crater C generated during the joining operation of the base metals 100 are approximately the same. This is because the volume of the protrusion 10 that satisfies Equations (3) and (4) is a volume that has a heat capacity that can withstand heat conduction equivalent to that of the base metal 100. Note that the protrusion 10 may have a thermal conductivity equal to or greater than that of the base metal 100, for example, by making the plate thickness of the protrusion 10 thicker than that of the base metal 100. In this case, the size of the molten pool and crater C formed on the protrusion 10 will be smaller than the size of the molten pool and crater C formed on the base metal 100.

[0042] In this embodiment, the planar shape of the protrusion 10 is a square with one side abutting the base material 100. However, the shape of the protrusion 10 is not limited to this as long as the molten pool and crater C formed on the protrusion 10 are contained within the protrusion 10 and the size of the molten pool formed on the protrusion 10 is the same as the size of the molten pool formed on the base material 100. In other words, the shape of the protrusion 10 is not limited to this as long as formulas (3) and (4) are satisfied. FIG. 11 shows an example of another planar shape of the protrusion 10. However, the planar shape of the protrusion 10 may be a triangular shape PS1 with one side abutting the base material 100, or a semicircular shape PS2 with the diameter abutting the base material, as long as it surrounds the protrusion 10. In FIG. 11, S20 shows a state in which the main body 20 is fixed to the base material 100 with the protrusion 10 abutting the base material end 100E. S30 shows a state in which the joining operation has been extended to the protrusion 10. S50 shows a state in which the connection portion 30 has melted through and the main body portion 20 has been fused away from the protrusion 10.

[0043] The runoff plate 1 can also be used for multiple types of welded joints. FIG. 12 illustrates examples of types of welded joints to which the runoff plate 1 according to this embodiment can be applied. For example, the runoff plate 1 can be used for a butt weld WT1 shown in FIG. 12A, a corner weld WT2 shown in FIG. 12B, a fillet weld WT3 shown in FIG. 12C, and a lap weld WT4 shown in FIG. 12D. In the diagram, t and 2t indicate the thickness of the base material 100 (101 or 102) or the runoff plate 1. Note that "butt weld" refers to a butt weld defined in JIS Z3001-1:2018 No. 11507 (ISO / TR25901-4:2016). A "corner joint" refers to a corner joint defined in JIS Z3001-1:2018 No. 11307 (ISO / TR25901-4:2016). "Fillet weld" refers to a fillet weld defined in JIS Z3001-1:2018 No. 11506 (ISO / TR25901-4:2016). "Lap joint" refers to a lap joint defined in JIS Z3001-1:2018 No. 11304 (ISO / TR25901-4:2016).

[0044] [Welding method using runoff plates] A welding method using the runoff plate 1 shown in Fig. 1 will be described with reference to Fig. 13A to Fig. 14. Fig. 13A to Fig. 13D are diagrams schematically showing the welding method using the runoff plate according to this embodiment. Fig. 14 is a flowchart showing the welding method using the runoff plate according to this embodiment.

[0045] In step S10 (FIG. 13A), for example, an operator abuts the protrusion 10 of the runoff plate 1 against the base material end 100E. Proceeding to step S20 (FIG. 13B), in this state, the runoff plate 1 is fixed to the base material 100 by fixing the main body 20. More specifically, the main body 20 is fixed to the base material 100 so that the connection portion 30 is positioned on an extension line of the weld joint 100J of the base material 100. The main body 20 may be fixed using a jig 50 or temporarily fixed by welding.

[0046] Proceeding to step S30 (FIG. 13C), an operator or processing machine performs the joining operation so that the molten pool passes through the base metal end 100E and fits within the protrusion 10, and the weld end reaches the connection 30. Proceeding to step S40 (FIG. 13D), heat generated during the welding operation is applied, melting the connection 30 and fusing the main body 20 from the protrusion 10. In step S40, when the joining operation is completed and the beam is turned off, the molten pool solidifies and becomes a crater C. Crater C is approximately the same size as the molten pool and, like the molten pool, fits within the protrusion 10. Proceeding to step S50 (FIG. 13E), the operator removes the protrusion 10 welded to the base metal 100. For example, the protrusion 10 is removed by grinding using a grinder. Note that other tools may be used as the removal method as long as the quality of the base metal end 100E after removal is maintained.

[0047] [Action and effect] As described above, the present embodiment provides the following advantageous effects.

[0048] The runoff plate 1 includes a protrusion 10 that abuts against the base metal end 100E, a main body 20 that is disposed around the protrusion 10 and fixed to the base metal 100 with the protrusion 10 abutting against the base metal end 100E, and a connection 30 that connects the protrusion 10 and the main body 20 and melts when heat generated during the joining operation is applied. This allows the weld end of the joining operation to be removed from the base metal 100, preventing defects caused by the joining operation from occurring in the base metal 100. By fixing the main body 20 to the base metal 100, the runoff plate 1 can fulfill its function. Furthermore, the runoff plate 1 of the present disclosure allows the main body 20 to remain in contact with the base metal 100 without directly conducting heat from the crater C. Furthermore, by extending the joining operation from the base material end 100E to the protrusion 10, the connection portion 30 can be melted away, and the connection portion 30 can easily separate the protrusion 10 and the main body 20 when the joining operation is completed. Therefore, the runoff plate 1 can fulfill its function as a runoff plate with the smallest contact surface with the base material 100. As a result, the amount of work required to remove the runoff plate 1 can be significantly reduced.

[0049] The connection portion 30 is a heat conduction path between the protrusion portion 10 and the main body portion 20. As a result, heat resulting from welding within the protrusion portion 10 cannot be conducted between the protrusion portion 10 and the main body portion 20 except through the connection portion 30. Therefore, the main body portion 20 will not melt except through heat conduction from the connection portion 30, so that changes in the shape and rigidity of the main body portion 20 due to melting can be prevented until the connection portion 30 melts down, and the abutting state can be reliably maintained until the connection portion 30 melts down.

[0050] The connecting portion 30 may connect the protruding portion 10 and the main body portion 20 at a position on an extension line of the weld joint 100J. This allows the connecting portion 30 to be melted down at a position on an extension line of the weld joint 100J.

[0051] The connection portion 30 is located at the end of the weld and is sized to melt away during the joining operation. This allows the joining operation to be extended from the base metal end 100E to the protrusion 10, allowing the connection portion 30 to be easily separated from the protrusion 10 and the main body 20 when the joining operation is completed. Therefore, the function of the runoff plate 1 can be realized with the smallest contact surface with the base metal 100. As a result, the amount of work required to remove the runoff plate 1 can be significantly reduced.

[0052] The protrusion 10 is thermally insulated from the main body 20 by a thermal insulating element, except for the connection portion 30. This prevents heat caused by welding within the protrusion 10 from being conducted between the protrusion 10 and the main body 20, except for the connection portion 30. Therefore, the main body 20 will not melt except through heat conduction from the connection portion 30, so that changes in the shape and rigidity of the main body 20 due to melting can be prevented until the connection portion 30 melts down, and the abutting state can be reliably maintained until the connection portion 30 melts down.

[0053] The size of the protrusion 10 is such that, when the connection portion 30 is positioned at the end of the weld, the molten pool and crater C formed at the protrusion 10 will fit within the protrusion 10, and the size of the molten pool formed at the protrusion 10 will be the same as or smaller than the size of the molten pool formed in the base material 100. In other words, the size of the protrusion 10 is such that it has a volume with a heat capacity capable of withstanding heat conduction equivalent to that of the base material 100, or a volume with a thermal conductivity equal to or greater than that of the base material 100. Therefore, the runoff plate 1 can be formed to have the function of a minimum-sized runoff plate while satisfying the mechanical contact requirements with the base material 100.

[0054] The base materials 100 are joined by laser welding, and if the longitudinal dimension of the welded joint 100J is defined as the length and the width dimension of the welded joint 100J is defined as the width, then the length 30L of the connection portion 30 satisfies formula (1), and the width 30W of the connection portion 30 satisfies formula (2). As a result, when joining the base materials 100, the size of the connection portion 30 can be determined based on the width BW of the bead B. Therefore, by applying heat generated during the joining operation to the connection portion 30, the connection portion 30 can be appropriately melted down.

[0055] The base materials 100 are joined by laser welding, and if the longitudinal dimension of the welded joint 100J is defined as the length and the width dimension of the welded joint 100J is defined as the width, the length 10L of the protrusion 10 satisfies formula (3), and the width 10W of the protrusion 10 satisfies formula (4). This allows the size of the protrusion 10 to be set to a size that does not cause defects in the base materials 100 and can significantly reduce the number of steps required for removal after the joining operation. Therefore, the number of steps required for removing the runoff plate 1 after the joining operation can be significantly reduced while improving the quality of the weld.

[0056] The main body 20 is fixed along the longitudinal direction of the welded joint 100J by two parallel clamp bands 52 (52U and 52L). If the longitudinal dimension of the welded joint 100J is defined as the length and the width dimension of the welded joint 100J as the width, the length 20L of the main body 20 satisfies formula (5), and the width 20W of the main body 20 satisfies formula (6). However, the length X is the minimum length necessary to provide an area required for the main body 20 to remain fixed without moving until the joining operation moves from the base material 100 to the protrusion 10 and the connection portion 30 melts through. The clamp spacing 52I is the distance between the two clamp bands 52 (52U and 52L), and the clamp pressure H is the width dimension of the welded joint 100J where one clamp band 52 fixes the main body 20. Therefore, the length 20L of the main body is the length of the protrusion 10 and the connection portion 30 plus the length X, and the width 20W of the main body is the clamp spacing 52I plus the holding margin H of the two clamps. This allows the area of ​​the main body 20 to be the area required to fix the main body 20 without moving even during the joining operation, and allows the welding operation to be performed with the protrusion 10 in contact with the base material end 100E.

[0057] The planar shape of the protrusion 10 is a quadrangle with one side abutting the base material. By making the planar shape of the protrusion 10 quadrangular, it is possible to easily form a quadrangular shape that satisfies the above formulas (3) and (4).

[0058] The planar shape of the protrusion 10 may be a triangle PS1 with one side abutting the base material 100, or a semicircular shape PS2 with the diameter abutting the base material 100. This allows the shape of the protrusion 10 to be changed in accordance with the shape of the jig that fixes the runoff plate 1 and the method for removing the protrusion.

[0059] The runoff plate 1 can be used for butt welding WT1, corner joint welding WT2, fillet welding WT3, and lap joint welding WT4, thereby preventing defects from occurring in the base material 100 in a variety of joining methods.

[0060] The welding end of the joining operation extended to the protrusion 10 is set at the position of the connection part 30. This makes it possible to remove the welding end of the joining operation from the base material 100, and prevents defects caused by the joining operation from occurring in the base material 100. [Explanation of symbols]

[0061] 1 Runoff Plate 10 Protrusion 20 Main body 30 Connection 40 slits 50 Jig 52 (52U and 52L) Clamp Band 52I Clamp Spacing 100 (101 and 102) base material 100J welded joint 100E Base metal end B bead BW Bead width C Crater CW crater length H Clamp pressure PS1 Triangular (shape of protrusion) PS2 semicircular shape (shape of protrusion) WM weld metal WT1 Butt Weld WT2 Corner Joint Welding WT3 fillet weld WT4 lap joint weld

Claims

1. A runoff plate that is fixed to a base metal end of a weld joint of the base metal when welding the base metal, and that does not leave a welding end portion of a joining operation for welding the base metal on the base metal, a protrusion that contacts the end of the base material; a main body portion disposed around the protrusion portion and fixed to the base material in a state in which the protrusion portion abuts against an end of the base material; a connection portion that connects the protrusion portion and the main body portion and melts down when heat generated during the joining operation is applied; A runoff plate comprising:

2. The connection portion is a heat conduction path between the protrusion portion and the main body portion. The runoff plate of claim 1 .

3. The connecting portion connects the protrusion and the main body portion at a position on an extension line of the welded joint. The runoff plate of claim 1 .

4. The connection portion is located at the end of the welding and is sized to melt away during the joining operation. The runoff plate of claim 1 .

5. The protrusion, except for the connection portion, is thermally insulated from the main body by a thermal insulating element. The runoff plate of claim 1 .

6. The connecting portion has a rigidity that holds the protrusion without deformation when the main body portion is fixed. The runoff plate of claim 1 .

7. The size of the protrusion is such that, when the connection portion is positioned at the welding end portion, the molten pool and crater generated at the protrusion are contained within the protrusion, and the size of the molten pool generated at the protrusion is equal to or smaller than the size of the molten pool generated in the base material. The runoff plate of claim 1 .

8. The base materials are joined by laser welding, When the dimension of the weld joint in the longitudinal direction is defined as the length and the dimension of the weld joint in the width direction is defined as the width, the length of the connection portion satisfies formula (1), and the width of the connection portion satisfies formula (2). The runoff plate of claim 1 . However, the bead is a raised portion of the weld metal that occurs during the joining operation, and the width of the bead falls within the range from the minimum value to the maximum value of the measured bead width. [Equation 1] Length of connection part = width of bead × 0.3 (1) [Equation 2] Connection width = bead width × 0.3 (2)

9. The base materials are joined by laser welding, When the dimension of the weld joint in the longitudinal direction is defined as the length and the dimension of the weld joint in the width direction is defined as the width, the length of the protrusion satisfies the formula (3), and the width of the protrusion satisfies the formula (4). The runoff plate of claim 1 . However, the bead is a raised portion of the weld metal that occurs during the joining operation, the bead width is within the range from the minimum to maximum measured bead width, and the crater is a depression that occurs at the end of the bead during the joining operation. [Equation 3] Length of protrusion ≧ length of crater (3) [Equation 4] Width of protrusion ≧ width of bead × 3 (4)

10. The main body is fixed along the longitudinal direction of the weld joint by two parallel clamp bands. When the longitudinal dimension of the weld joint is defined as the length and the width dimension of the weld joint is defined as the width, the length of the main body satisfies formula (5) and the width of the main body satisfies formula (6). The runoff plate of claim 1 . however, X is the minimum length necessary to provide an area required for the main body portion to be fixed without moving until the joining operation moves from the base material to the protrusion portion and the connection portion melts down, Clamp spacing is the distance between the two clamp bands; The clamping margin is the dimension in the width direction of the weld joint where the clamp band secures the main body portion. [Equation 5] Length of main body ≧ length of protrusion + length of connection + X (5) [Equation 6] Width of main body ≧ clamp spacing + (2 × clamp pressure) (6)

11. The planar shape of the protrusion is a quadrangle with one side abutting against the base material. The runoff plate of claim 1 .

12. The planar shape of the protrusion is a triangle with one side abutting against the base material, or a semicircular shape with a diameter portion abutting against the base material. The runoff plate of claim 1 .

13. Can be used for butt welding, corner welding, fillet welding, and lap welding The runoff plate of claim 1 .

14. A welding method using the runoff plate according to claim 1, The protrusion is brought into contact with an end of the base material of the weld joint, The main body is fixed to the base material. The joining operation is extended from the end of the base material to the protrusion, and the connection portion is melted down. After the joining operation, the protrusion welded to the base material is removed. A welding method using runoff plates.

15. The welding end of the joining operation extending to the protrusion is set at the position of the connection portion. A welding method using the runoff plate according to claim 14.

16. The main body is fixed to the base material so that the connection portion is located on an extension line of the weld joint. A welding method using the runoff plate according to claim 15.

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