1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16967 Aluminum Resistance Spot Welding Copyright 2013 General Motors Company All Rights Reserved May 2013 Page 1 of 7 1 Scope Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between t
2、he English and domestic language, the English language shall take precedence. 1.1 Purpose. This specification provides the acceptance criteria for aluminum resistance spot welding in automotive products for which GM is responsible for establishing or approving product design. 1.2 Applicability. The
3、criteria established in this specification become mandatory when referenced on a product release document or Statement of Requirements (SOR). Deviation from any weld criteria provided in this specification must be approved by Product Engineering. 1.3 Usage. Welds are considered satisfactory when the
4、y meet the expected design service loads and satisfy functional performance requirements. The evaluation criteria contained in this document has been established as a basis for the manufacturing acceptance of welded products and are the same for all welds regardless of service load. Furthermore, wel
5、ds identified as discrepant often retain a percentage of their mechanical properties and may contribute to the integrity of the welded product. Application of this specification for other uses, such as post-crash weld quality assessment, may lead to erroneous results or conclusions. 1.4 Clarificatio
6、n. For clarification of this specification or editorial comments, email the GM Weld Council at . 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ISO 4063 ISO 17677-1 2.2 GM Standards/Specifications. GM4491M GMW15
7、563 GMN3903 3 Requirements 3.1 General Acceptance Criteria. 3.1.1 Categories of Spot Welds. 3.1.1.1 Structural spot welds are required for performance of the welded product. All spot welds are structural unless specifically noted as process welds on the weld design document. 3.1.1.2 Process spot wel
8、ds are to facilitate in-process assembly but are not required for structural performance of the product. Process welds are exempt from the measurable acceptance criteria contained in this standard. 3.1.2 Process Adjustment Criteria. 3.1.2.1 Extra Welds. Any assembly having more welds than specified
9、on the weld design document shall have the welding process adjusted. 3.1.2.2 Distortion. Spot welds in which the surfaces are distorted more than 15 degrees from the normal plane shall have the welding process adjusted to original qualified procedure reduce or eliminate the distortion. See Figure 1.
10、 Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16967 Copyright 2013 General Motors Company All Rights Reserved May 2013 Page 2 of 7 Fig
11、ure 1: Weld Distortion 3.1.2.3 Indentation. Spot welds in which the depth of the depression on the surface (caused by the welding electrode) results in the reduction of the metal thickness of any individual layer that exceeds 20% shall have the welding process adjusted to the original qualified proc
12、edure to reduce the amount of indentation. 3.1.2.4 Internal Porosity. Different types of pores or voids may be observed during macro cross section examination. Internal porosity that is greater than 30% of the fusion zone area shall have the process adjusted to the original qualified procedure. 3.1.
13、2.5 Penetration. Penetration is the percent of the layer thickness that is fused. Welds with penetration less than 20% shall have the welding process adjusted to the original qualified procedure. 3.1.2.6 Weld Surface Appearance. Weld surface appearance requirements are not part of this standard. Wel
14、d surface appearance criteria are to be addressed through the appropriate use of Product Quality Standards (PQS). 3.2 Visual Acceptance Criteria. 3.2.1 Weld Quantity. The number of welds installed on the product must agree with the quantity specified on the weld design document. The pattern is nonco
15、nforming if the number of welds installed on the product is less than the specified. 3.2.2 Cracks. Spot welds with visible cracks on the surface are discrepant. See Figure 2. Figure 2: Surface Cracks 3.2.3 Holes. Spot welds shall be free of hole(s) extending through the weld. Spot welds with holes e
16、xtending through the weld are discrepant. 3.2.4 Location/Edge Weld. A spot weld, as defined by the impression left by the electrodes, is to be located as shown on the weld design document. Welds with imprints that break or deform the original edge of the weld flange are discrepant. See Figure 3. Wel
17、ds with imprints that overlap each other are discrepant. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16967 Copyright 2013 General Mot
18、ors Company All Rights Reserved May 2013 Page 3 of 7 Figure 3: Edge Weld 3.3 Measurable Acceptance Criteria. 3.3.1 Location/Spacing for Welds. Welds installed on the product must be within 10 mm from a location specified by a template (provided by Engineering) to be acceptable. When a template is no
19、t provided by Engineering, welds are acceptable provided the weld is within 20 mm of the location indicated on the weld design document. 3.3.2 Weld Size. 3.3.2.1 Two (2) Thickness Welds. To determine the acceptable weld size for a two thickness weld (two loose pieces or one loose to two previously w
20、elded), use the metal thickness (t) of the thinner of the two layers being welded to determine the weld size as listed in Table 1. A spot weld whose measured plug diameter or nugget width is equal to or larger than the appropriate value in Table 1 is an acceptable weld. 3.3.2.2 Three (3) Thickness W
21、elds. Three thickness welds in aluminum will potentially have a different weld size requirement at each interface. To determine the acceptable weld size for a three thickness weld (three loose pieces) use the metal thickness (t) of the thinner of the two layers at any interface to determine the acce
22、ptable weld size. However, in the case where the thinnest layer is stacked between two heavier layers use the second thickest piece (t) to determine the acceptable weld size for both welds. A spot weld whose measured plug diameter or nugget width is equal to or larger than the appropriate value in T
23、able 1 is an acceptable weld. Table 1: Minimum Acceptable Weld Size Note 1 Metal Thickness (t) (mm) Weld Size (mm) 0.60 to 0.70 3.0 0.71 to 0.90 3.5 0.91 to 1.10 4.0 1.11 to 1.40 4.5 1.41 to 1.70 5.0 1.71 to 2.00 5.5 2.01 to 2.40 6.0 2.41 to 2.80 6.5 2.81 to 3.20 7.0 3.21 to 3.60 7.5 Note 1: More th
24、an three thickness welding is not covered by this table. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16967 Copyright 2013 General Mot
25、ors Company All Rights Reserved May 2013 Page 4 of 7 3.3.2.3 Plug Diameter. The plug (button) is that part of the weld that tears out in a peel test. The size of a plug is calculated by adding the diameter of the major axis to the diameter of the axis perpendicular at the midpoint of the major axis
26、and dividing by 2. See Figure 4. The measurements are to be taken at the faying surface. Figure 4: Plug/Button Size Depending on the aluminum alloy and type of loading a plug or button may not always result from destructive testing. In these specific cases (interfacial fracture), a macro section exa
27、mination of the fusion zone must be used to determine acceptability. 3.3.2.4 Nugget Width. The nugget weld size is the width of the fusion zone omitting the heat affected zone (HAZ) measured from a macro section examination or weld cross section. See Figure 5. Figure 5: Macro Section Measurement Cop
28、yright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16967 Copyright 2013 General Motors Company All Rights Reserved May 2013 Page 5 of 7 3.4 Dis
29、position/Repair Procedure. 3.4.1 Spot Weld Pattern Conformance Criteria. A pattern is a collection of spot welds to which a tolerance is applied to meet structural requirements and for determining manufacturing acceptance of the product. The default pattern is all structural spot welds on the struct
30、ure installed at the same manufacturing plant. The quantity tolerance for the single default pattern is no more than 5% of the total weld count can be discrepant. The spot weld pattern/product is conforming when the number of acceptable spot welds (not discrepant per the requirements of this standar
31、d) within the pattern meets or exceeds the pattern tolerance. Disposition of product nonconforming to this standard shall be handled in accord with GM approved procedures for nonconforming material. Note: Two or more adjacent missing or breaking welds cause pattern nonconformance regardless of the q
32、uantity tolerance. Structural spot welds with holes cause the pattern to be nonconforming regardless of the quantity tolerance. 3.4.2 Repair Procedures. Weld repair methods for discrepant welds are described in Appendix A, Table A1. Arc weld repair of joints containing sealer or adhesive is not perm
33、itted. An exception to the specified repair methods may be permitted provided there is a documented review and approval by the responsible Product Engineer. 3.4.2.1 Resistance Spot Weld Repair. Spot weld with a weld gun that is qualified for the material types and thicknesses to be welded. One repai
34、r spot weld shall be added for each spot weld being repaired. Repair spot welds must meet the requirements of this standard. 3.4.2.2 Plug Weld Repair. For each spot being repaired, plug weld using either Gas Metal Arc Welding (MIG) or Gas Tungsten Arc Welding (TIG). The plug weld shall conform to GM
35、4491M. All repair personnel using this method of repair must be periodically qualified and approved following local procedures. 3.4.2.3 Arc Weld Repair. A MIG or TIG fillet or edge weld may be used for two metal thickness joints. The repair weld must be located as close as possible to the original d
36、esignated weld location and must be a minimum of 20 mm of effective length. The repair welds must conform to GMN3903. All repair personnel using this method of repair must be periodically qualified and approved following local procedures. 4 Manufacturing Process 4.1 Process Control. The welding sour
37、ce is responsible for establishing practices and test methods to assure that the criteria of this standard are met, and are consistent with GMW15563, GM Joining and Dispense Process Control Procedure. 5 Notes 5.1 Glossary. Welding terms used in this specification shall be interpreted in accordance w
38、ith the definitions provided in the latest edition of ISO 17677-1, Resistance Welding Vocabulary Part 1: Spot, Projection and Seam Welding. Qualified Procedure: The equipment listing, settings and weld parameters that were established during Manufacturing Validation and are documented on the Weld To
39、ol Information Sheets. 5.2 Acronyms, Abbreviations, and Symbols. HAZ Heat Affected Zone MIG Gas Metal Arc Welding with Solid Wire Electrode (ISO 4063 Process Reference Number 131) PQS Product Quality Standard SOR Statement of Requirements TIG Gas Tungsten Arc Welding (ISO 4063 Process Reference Numb
40、er 141) 6 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: GMW16967 Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE
41、 ENGINEERING STANDARDS GMW16967 Copyright 2013 General Motors Company All Rights Reserved May 2013 Page 6 of 7 7 Release and Revisions This standard was originated in May 2013. It was first approved by GM Global Weld Council in May 2013. It was first published in May 2013. Issue Publication Date Des
42、cription (Organization) 1 MAY 2013 Initial publication. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16967 Copyright 2013 General Moto
43、rs Company All Rights Reserved May 2013 Page 7 of 7 Appendix A: Weld Repair Methods for Aluminum Resistance Spot Welds Table A1: Repair Methods Weld Discrepancy Description GMW16967 Reference Paragraph Repair Methods Missing Weld Weld omitted 3.2.1 Install spot weld, or plug weld at correct location
44、 Note 1 Visible Cracks Visible crack(s) on surface 3.2.2 Grind to remove crack and arc weld Note 1 Holes Hole in the weld 3.2.3 Arc weld to eliminate hole Note 1 Location/Edge Weld Original trim edge deformed by spot weld 3.2.4 Install spot weld, or plug weld in the correct location Note 1, Note 2 M
45、islocated Weld Welds not located within 10 mm of the location shown on product weld design document 3.3.1 Install spot weld, plug weld, or arc weld at correct location Note 1 Weld Size Button/nugget size is less than specified in Table 1 3.3.2 Install spot weld with weld size greater than or equal t
46、o the value specified in Table 1 Note 1: Arc weld repairs are only allowed provided there is no sealer or adhesive in the joint. Arc weld repairs must meet the requirements of GMN3903. Note 2: Spot welds that are edge welds may be repaired by placing a new spot weld in the correct location, overlapp
47、ing the original weld if necessary. Prior to installing the new spot weld, the edge weld should be separated so that the weld current producing the new weld is not degraded due to shunting. Care needs to be taken when separating the edge weld to avoid tearing the metal. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
