Technological method for repairing spot welding dent depth of stainless steel sheet by TIG (Tungsten Inert Gas) welding

Abstract

The invention discloses a process method for repairing the spot welding dent depth of a stainless steel sheet through TIG welding. The process method mainly comprises the following steps that S1, a defect test sample piece is manufactured; s2, spot welding defects are repaired in a TIG welding mode, and the strength of a repaired spot welding spot is determined through a spot welding tensile test; s3, spot welding defects are repaired in a TIG welding mode, and it is determined that the weld nugget diameter of a repaired spot welding spot meets the standard requirement through a macroscopic metallographic test mode; and S4, chemical passivation is conducted on the surface of the welding spot, and oxidation color cleaning and passivation treatment are conducted on the surface of the welding spot subjected to welding repair through a chemical reagent. According to the process method, the process steps are defined through experiments, the repairing key points are refined, the defects of the spot welding spots are finally repaired, then the product quality is met, the manufacturing cost is reduced, and smooth production is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rail car production, and in particular to a process method for repairing deep point welding indentation of stainless steel sheet by TIG welding. BACKGROUND

[0002] At present, in the export subway project, the export subway has its designated execution standard, and the stainless steel resistance spot welding is one of the main welding methods of the car body steel structure, which has clear requirements for the nugget diameter, weld mark depth and weld point strength of the spot welding spot of different plate thickness combinations. In actual production, due to the aging of manufacturing equipment, personnel operation, material gap between parts, etc., the quality of the spot welding indentation depth does not meet the standard requirements, thereby affecting the strength of the product, and in serious cases, the product needs to be scrapped, which ultimately affects the manufacturing cost and production efficiency.

[0003] Therefore, based on the above technical problems, the technical personnel in the field urgently need to develop a process method for repairing deep point welding indentation of stainless steel sheet by TIG welding. SUMMARY

[0004] The purpose of the present application is to provide a process method for repairing deep point welding indentation of stainless steel sheet by TIG welding. Through actual problem verification, the repair process and method are clear, the repair points are detailed, and the defects of spot welding points exceeding the standard are repaired, thereby meeting the product quality, reducing the manufacturing cost, and ensuring the smooth production.

[0005] In order to achieve the above purpose, the present application provides the following technical scheme:

[0006] The process method for repairing deep point welding indentation of stainless steel sheet by TIG welding mainly includes the following steps:

[0007] S1, defect test sample production, using a stainless steel sheet combination defect test sample with a spot welding weld mark depth exceeding 0.4mm, which is composed of a plate thickness of 0.6mm and 1.0mm as a base material combination;

[0008] S2, repairing the spot welding defects by TIG welding, and determining the strength of the repaired spot welding spot by spot welding tensile test, and finally determining that the TIG welding repair meets the strength requirement;

[0009] S3, repairing the spot welding defects by TIG welding, and determining that the nugget diameter of the repaired spot welding spot meets the standard requirement by macroscopic metallographic test, and finally determining that the TIG welding repair meets the nugget diameter requirement;

[0010] S4. Chemical passivation of solder joint surface: Chemical reagents are used to clean and passivate the surface of the solder joint after welding repair by removing oxidation color.

[0011] Furthermore, step S1 mainly includes the following steps:

[0012] S101. Prepare welding defect samples by welding thin plates with a base material thickness of 0.6 mm and 1.0 mm using stainless steel. Prepare 5 defect samples, namely sample 1, sample 2, sample 3, sample 4 and sample 5.

[0013] The weld indentation depths of the five defective samples were 0.5 mm, 0.44 mm, 0.54 mm, 0.51 mm and 0.50 mm, respectively.

[0014] Furthermore, step S2 mainly includes the following steps:

[0015] S201. TIG repair welding is performed on the 5 defective samples in step S101, and the TIG repair welding method adopts manual wire filling.

[0016] S202. Perform a tensile test on the defective sample after welding in step S201 to verify that the strength meets the requirements.

[0017] Furthermore, the standard parameters for the tensile test in step S202 are the strength values ​​for the corresponding plate thickness in the AWS C1.1M / C1.1-2012 resistance welding specification, and must be 1.2 times the standard value.

[0018] The static tensile strength of the sheet metal with a thickness of 0.6 mm is 3.2 kN.

[0019] Furthermore, step S3 includes the following steps:

[0020] S301. Prepare sample 6 and sample 7 according to steps S101 and S201, and sample 6 and sample 7 after TIG repair welding are sampled, cut, processed and chemically etched, and then low magnified metallographic observation is performed.

[0021] Furthermore, step S3 also includes the following steps:

[0022] S302. In step S301, the weld nugget diameter inspection standard parameter is implemented according to the weld nugget diameter corresponding to the plate thickness in the AWS C1.1M / C1.1-2012 resistance welding specification. For a thin plate of 0.6mm, the weld nugget diameter after electric welding is 3.05mm, and the weld nugget diameter after TIG repair welding is more than 5mm.

[0023] Furthermore, step S4 includes the following steps:

[0024] S401. Use chemical reagents to remove oxide color from the surface after TIG repair welding to ensure its appearance and rust prevention requirements.

[0025] The present invention provides a process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding, which has the following beneficial effects:

[0026] The process method of this invention clarifies the process steps through experiments, refines the key points of repair, and ultimately achieves the repair of spot welding defects, thereby meeting product quality requirements, reducing manufacturing costs, and ensuring smooth production. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0028] Figure 1a This is a photograph of sample 1 in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0029] Figure 1b This is a photograph of sample 1 after TIG repair welding in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0030] Figure 1c This is a photograph of sample 1 after stretching in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0031] Figure 2a This is a photograph of sample 2 in step S2 of a process method for repairing deep spot weld indentations on a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0032] Figure 2b This is a photograph of sample 2 after TIG repair welding in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0033] Figure 2c This is a photograph of sample 2 after stretching in step S2 of a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0034] Figure 3aThis is a photograph of sample 3 in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0035] Figure 3b This is a photograph of sample 3 after TIG repair welding in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0036] Figure 3c This is a photograph of sample 3 after stretching in step S2 of a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0037] Figure 4a This is a photograph of sample 4 in step S2 of a process method for repairing deep spot weld indentations on a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0038] Figure 4b This is a photograph of sample 4 after TIG repair welding in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0039] Figure 4c This is a photograph of sample 4 after stretching in step S2 of a process method for repairing deep spot weld indentations on a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0040] Figure 5a This is a photograph of sample 5 in step S2 of a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0041] Figure 5b This is a photograph of sample 5 after TIG repair welding in step S2 of a process method for repairing deep spot weld indentations in a thin stainless steel plate using TIG welding, as disclosed in an embodiment of the present invention.

[0042] Figure 5c This is a photograph of sample 5 after stretching in step S2 of a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0043] Figure 6a This is a photograph of sample 6 after cutting, which is a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding disclosed in an embodiment of the present invention.

[0044] Figure 6b This is a photograph of the sampling location of sample 6, which is a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0045] Figure 6cThis is a macroscopic metallographic image of sample 6, which is a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0046] Figure 6d This is a schematic diagram of sample 6, which is a sample of a process for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention. The original weld nugget diameter is 4.98 mm.

[0047] Figure 6e This is a schematic diagram of sample 6, which shows a weld nugget of 5.65 mm after TIG welding, in a process method for repairing deep spot weld indentations in stainless steel thin plates disclosed in an embodiment of the present invention.

[0048] Figure 7a This is a photograph of sample 7 after cutting, which is a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding disclosed in an embodiment of the present invention.

[0049] Figure 7b This is a photograph of the sampling location of sample 7, which is a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0050] Figure 7c This is a macroscopic metallographic image of sample 7, which is a process method for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention.

[0051] Figure 7d This is a schematic diagram of sample 7, which is a sample of a process for repairing deep spot weld indentations in stainless steel thin plates using TIG welding, as disclosed in an embodiment of the present invention. The original weld nugget diameter is 5.98 mm.

[0052] Figure 7e This is a schematic diagram of sample 7, which shows a weld nugget of 5.67 mm after TIG welding, in a process method for repairing deep spot weld indentations in stainless steel thin plates disclosed in an embodiment of the present invention.

[0053] Figure 8 This is a process flow diagram of a method for repairing deep spot weld indentations on thin stainless steel plates using TIG welding, as disclosed in an embodiment of the present invention. Detailed Implementation

[0054] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0055] See Figures 1a to 7e As shown;

[0056] This embodiment presents a process for repairing deep spot weld indentations on thin stainless steel plates using TIG welding. The process mainly includes the following steps, see below.Figure 8 As shown:

[0057] S1. Defect test specimen fabrication: The defect test specimen is made of stainless steel thin plates with a weld depth exceeding 0.4mm, using a combination of base materials with a thickness of 0.6mm and 1.0mm and spot welds.

[0058] S2. TIG welding was used to repair spot welding defects, and the strength of the repaired spot weld was determined by spot welding tensile test. Finally, it was determined that the TIG welding repair met the strength requirements.

[0059] S3. TIG welding is used to repair spot weld defects, and macroscopic metallographic tests are used to determine that the weld nugget diameter of the repaired spot weld meets the standard requirements. Finally, top-removed TIG welding repair meets the weld nugget diameter requirements.

[0060] S4. Chemical passivation of solder joint surface: Chemical reagents are used to clean and passivate the surface of the solder joint after welding repair by removing oxidation color.

[0061] Furthermore, step S1 mainly includes the following steps:

[0062] S101. Prepare welding defect samples by electric welding on stainless steel base plates with a thickness of 0.6 mm and 1.0 mm. The equipment used for electric welding is the same as the equipment used in actual production. Prepare 5 defect samples, namely sample 1, sample 2, sample 3, sample 4 and sample 5.

[0063] The weld indentation depths of the five defective samples were 0.5 mm, 0.44 mm, 0.54 mm, 0.51 mm and 0.50 mm, respectively.

[0064] Preferably, step S2 in this embodiment mainly includes the following steps:

[0065] S201. TIG repair welding is performed on the 5 defective samples in step S101, and the TIG repair welding method adopts manual wire filling.

[0066] S202. Perform a tensile test on the defective sample after welding in step S201 to verify that the strength meets the requirements.

[0067] Preferably, in step S202 of this embodiment, the standard parameters for the tensile test are the strength values ​​for the corresponding plate thickness in the AWS C1.1M / C1.1-2012 resistance welding specification, and the values ​​must be 1.2 times the standard values.

[0068] The static tensile strength of the sheet metal with a thickness of 0.6 mm is 3.2 kN. TIG welding repaired the weld, and the weld strength met the standard requirements. This method is based on the AWS standard; for specific problems, the standard requirements can be followed.

[0069] Table 1. Information related to defective sample repair

[0070]

[0071] Preferably, step S3 in this embodiment includes the following steps:

[0072] S301. Prepare sample 6 and sample 7 according to steps S101 and S201, and sample 6 and sample 7 after TIG repair welding are sampled, cut, processed and chemically etched, and then low magnified metallographic observation is performed.

[0073]

[0074]

[0075] Preferably, step S3 in this embodiment further includes the following step:

[0076] S302. In step S301, the weld nugget diameter inspection standard parameter is implemented according to the weld nugget diameter corresponding to the plate thickness in the AWS C1.1M / C1.1-2012 resistance welding specification. For a thin plate of 0.6mm, the weld nugget diameter after electric welding is 3.05mm, and the weld nugget diameter after TIG repair welding is more than 5mm.

[0077] Preferably, step S4 in this embodiment includes the following steps:

[0078] S401. Use chemical reagents to remove oxide color from the surface after TIG repair welding to ensure its appearance and rust prevention requirements.

[0079] The present invention provides a process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding, which has the following beneficial effects:

[0080] The process method of this invention clarifies the process steps through experiments, refines the key points of repair, and ultimately achieves the repair of spot welding defects, thereby meeting product quality requirements, reducing manufacturing costs, and ensuring smooth production.

[0081] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding, characterized in that, The process mainly includes the following steps: S1. Defect test specimen fabrication: The defect test specimen is made of stainless steel thin plates with a weld depth exceeding 0.4mm, using a combination of base materials with plate thicknesses of 0.6mm and 1.0mm. S2. TIG welding was used to repair spot welding defects, and the strength of the repaired spot weld was determined by spot welding tensile test. Finally, it was determined that the TIG welding repair met the strength requirements. S3. TIG welding is used to repair spot weld defects, and macroscopic metallographic tests are used to determine that the weld nugget diameter of the repaired spot weld meets the standard requirements. Finally, top-removed TIG welding repair meets the weld nugget diameter requirements. S4. Chemical passivation of solder joint surface: Chemical reagents are used to clean and passivate the surface of the solder joint after welding repair by removing oxidation color.

2. The process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding according to claim 1, characterized in that, Step S1 mainly includes the following steps: S101. Prepare welding defect samples by welding thin plates with a base material thickness of 0.6 mm and 1.0 mm using stainless steel. Prepare 5 defect samples, namely sample 1, sample 2, sample 3, sample 4 and sample 5. The weld indentation depths of the five defective samples were 0.5 mm, 0.44 mm, 0.54 mm, 0.51 mm and 0.50 mm, respectively.

3. The process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding according to claim 2, characterized in that, Step S2 mainly includes the following steps: S201. TIG repair welding is performed on the 5 defective samples in step S101, and the TIG repair welding method adopts the manual wire filling method. S202. Perform a tensile test on the defective sample after welding in step S201 to verify that the strength meets the requirements.

4. The process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding according to claim 3, characterized in that, The standard parameters for the tensile test in step S202 are the strength values ​​for the corresponding plate thickness in the AWS C1.1M / C1.1-2012 resistance welding specification, and must be 1.2 times the standard value. The static tensile strength of the sheet metal with a thickness of 0.6 mm is 3.2 kN.

5. The process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding according to claim 3, characterized in that, Step S3 includes the following steps: S301. Prepare sample 6 and sample 7 according to steps S101 and S201, and sample 6 and sample 7 after TIG repair welding are sampled, cut, processed and chemically etched, and then low magnification metallographic observation is performed.

6. The process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding according to claim 5, characterized in that, Step S3 further includes the following steps: S302. In step S301, the weld nugget diameter inspection standard parameters are executed according to AWS. The C1.1M / C1.1-2012 resistance welding specification specifies the weld nugget diameter for the corresponding plate thickness. For a 0.6mm thin plate, the weld nugget diameter after electric welding is 3.05mm, and after TIG repair welding, the weld nugget diameter is 5mm or more.

7. A process for repairing deep spot weld indentations in thin stainless steel plates using TIG welding according to claim 6, characterized in that, Step S4 includes the following steps: S401. Use chemical reagents to remove oxide color from the surface after TIG repair welding to ensure its appearance and rust prevention requirements.

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