1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16435 Weld Acceptance Criteria and Repair Procedures for Resistance Projection Welding - Steel Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 1 of 7 1 Scope Note: Nothing in this standard supercedes applicable l
2、aws and regulations. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. This standard provides the acceptance criteria and repair procedures for Resistance Projection Welding. 1.2 Applicability. This standard applies to
3、the resistance projection welding of embossed projections. Criteria for welding of coined projections are specified in GMW16215 “Welding Acceptance Criteria and Repair Procedures: Resistance Projection Welded Steel Nuts, Studs, Cages and Other Parts with Solid Coined Projections”. The criteria estab
4、lished in this standard become mandatory when referenced on a product drawing or Statement of Requirements. Deviation from any acceptance criteria provided in this standard shall be identified on the product drawing or Statement of Requirements. 1.3 Usage. Welded structures are considered satisfacto
5、ry when they carry the intended service loads for a required period. Service loads on weldments in a vehicle are varied in both type and magnitude and cannot be addressed by this standard. Therefore, while the weld quality criteria of this standard are consistent with service loading requirements, t
6、hey have been established specifically for use in process and product monitoring. Any attempted application of this document to other uses, such as post-crash weld quality assessment, may lead to an erroneous result or conclusion. Discrepant welds by retaining a portion of their engineering properti
7、es may still contribute to the integrity of the assembly. 1.4 Clarification. For clarification of this standard or editorial comments, email the GM Global Weld Council at . 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifi
8、cations. None 2.2 GM Standards/Specifications. GM4491M GMW14058 GMW14057 GMW15563 2.3 Additional References. Body Opening Appearance Perceptual Quality Best Practices (The supplier shall work with the GM responsible engineer to comprehend this requirement.) GM Global Weld Council at . 3 Requirements
9、 3.1 General Acceptance Criteria. 3.1.1 Individual Projection Weld Criteria. There are multiple visual and measurable attributes that describe projection weld quality. These attributes are divided into two categories, criteria that cause the weld to be discrepant, and criteria that is undesirable fo
10、r appearance or processing and require the process to be adjusted to the qualified setup. 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 GM
11、W16435 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 2 of 7 3.1.2 Categories of Projection Welds. There are two categories of projection welds: structural and process. 3.1.2.1 Structural Projection Welds. Structural projection welds are installed for performance of the
12、 welded product. All projection welds are structural unless specifically noted as process welds on the weld design document. 3.1.2.2 Process Projection Welds. Process projection welds are installed to facilitate in-process assembly, but are not required for structural performance of the product. Pro
13、cess projection welds must be approved by Product and Manufacturing Engineering and shown on the weld design document. Process welds containing holes or cracks should be repaired. 3.2 Visual Acceptance Criteria. 3.2.1 Cracks. Projection welds having surface cracks that are visible without the aid of
14、 magnification whether in or around the weld cause the weld to be discrepant. 3.2.2 Holes. A hole is a perforation in the weld that allows light to travel through the material from one exterior surface to the opposing exterior surface. Projection welds that contain holes extending through the weld a
15、re discrepant and cause the product to be nonconforming regardless of the pattern tolerance. 3.2.3 Missing Welds. Whenever fewer welds exist in the product than are specified on the weld design document, the omitted welds are discrepant. 3.2.4 Perceptual Quality Requirements. Projection welds visibl
16、e to the customer in strategic areas of the body are to be considered Perceptual Quality (PQ) welds (reference the Body Opening Appearance Perceptual Quality Best Practices Weld Appearance Zone Diagrams). Product Quality Standards are to be utilized to document the appearance acceptance standards ad
17、dressing the desired weld precision (alignment, spacing, concentricity) and prominence (surface marking, indentation, distortion, pits, spatter and whiskers). Projection welds not meeting appearance standards shall have the process adjusted to the original qualified setup to eliminate the undesirabl
18、e condition. 3.3 Measurable Acceptance Criteria. 3.3.1 Quantity of Welds. The number of welds installed shall agree with welds specified on the weld design document. Missing or welds not installed are discrepant. 3.3.2 Location. A projection weld whose center point is installed further than 10 mm fr
19、om the design nominal location or whose edge distance “d” or “e” is located closer than 1.0 mm and 2.5 mm respectively from the trim edge of the embossed part (as shown in Figure 1) is discrepant. Figure 1: Edge Location Example Copyright General Motors Company Provided by IHS under license with Gen
20、eral Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16435 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 3 of 7 3.3.3 Weld Size. Weld size may be determined by either measuring the w
21、eld button or weld nugget. The weld button size for a linear projection weld is the length of the button. The weld button size for a spherical projection is determined by adding the measurement of the major axis to the measurement of the minor axis and dividing by 2 (see Figure 2). Measurements are
22、to be taken at the faying surface. Linear Projection Button Measurement Spherical Projection Button Measurement Figure 2: Projection Weld Button Measurement Examples The weld nugget size is the weld size measurement achieved by examining the macro section of a weld cross section and measuring the di
23、mensions of the fusion zone. The weld nugget size for a linear projection weld is the length of the fusion zone taken from a longitudinal cross section. The weld nugget size for a spherical projection weld is the width of the fusion zone at the base of the projection (see Figure 3). Longitudinal Cro
24、ss Section of Linear Projection Weld Cross Section of a Spherical Projection Weld Figure 3: Projection Weld Nugget Size Measurement Examples Projection welds whose weld button or nugget size is smaller than shown in Table 1 are discrepant. Table 1: Minimum Weld Size Projection Shape Required Weld Si
25、ze Linear Projection 80% of the embossed projection weldable length Spherical Projection 65% of the of the embossed projection diameter 3.3.4 Non-fused Welds. Weld locations that do not show evidence of welding (measureable button or plug) after destruct test are classified as non-fused. Non-fused w
26、elds are discrepant. 3.4 Disposition/Repair Procedure. 3.4.1 Disposition. Manufacturing product acceptance is based on all resistance projection weld patterns conforming. A weld pattern conforms to this standard when the number of non-discrepant welds (see 3.1, 3.2, and 3.3) within the pattern meets
27、 or exceeds the weld pattern tolerance, and there are no welds with holes, and no adjacent welds in the pattern that are known or suspected to be missing or non-fused. 3.4.2 Repair Procedures. When repair is required, projection welds shall be repaired according to the procedures specifically author
28、ized by the Product Release Engineer. In the absence of an engineering approved repair procedure, the following repair methods shall be used in the listed order of preference as shown in Table A1 of Appendix A. Copyright General Motors Company Provided by IHS under license with General Motors Compan
29、yNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16435 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 4 of 7 3.4.2.1 Repair by Resistance Spot Welding. Spot weld with a weld gun that is qualified f
30、or the metal types and thicknesses to be welded. One repair spot weld shall be added for each projection weld being repaired. Resistance spot welds shall meet the requirements of GMW14057. Locate repair spot welds within 10 mm of the designated nominal weld location (overlapping the existing project
31、ion weld is acceptable). Surface reprocessing may be required for welds located on visible weld surfaces. 3.4.2.2 Repair by Plug Welding. For each weld location being repaired, drill a hole in the top sheet in accord with the nominal holes sizes specified in GM4491M. The hole is to be filled by eith
32、er arc braze welding, or Gas Metal Arc Welding (MIG) welding. Plug welding should not be used if there is sealer or adhesive at the interface. The MIG welding process shall not be used if either sheet is thinner than 1.2 mm. The repair plug weld shall conform to GM4491M. Locate repair plug weld with
33、in 10 mm of the designated nominal weld location (overlapping the existing projection weld is acceptable). All repair personnel using this method of repair must be periodically qualified and approved following local procedures. Surface reprocessing is required for plug welds located on visible weld
34、surfaces. 3.4.2.3 Repair by Lap Fillet Braze/Weld. For each projection weld being repaired, create a 25 mm long lap fillet weld using the arc braze welding process; or create a 20 mm long lap fillet weld using the MIG welding process. A lap fillet weld should not be used if there is sealer or adhesi
35、ve at the interface. The MIG welding process is not to be used if either sheet is thinner than 1.2 mm. The repair weld shall conform to GMW14058. Locate the repair weld within 10 mm of the original designated weld location. All repair personnel using this method of repair must be periodically qualif
36、ied and approved following local procedures. Surface reprocessing is required for welds located on visible weld surfaces. 3.4.2.4 Repair by Arc Spot Welding. For each projection weld being repaired, install an arc spot weld (arc spot brazing is not allowed). Arc spot welding should not be used if th
37、ere is sealer or adhesive at the interface. Arc spot welding is not to be used if either sheet is thinner than 1.2 mm. The arc spot weld shall conform to GM4491M. Locate the repair arc spot weld within 10 mm of the original designated weld location (overlapping the existing projection weld is accept
38、able). The arc spot process and the repair personnel using this method of repair must be periodically qualified and approved following local procedures. Surface reprocessing is required for welds located on visible weld surfaces. 4 Manufacturing Process 4.1 Process Control. The welding source is res
39、ponsible for establishing practices and test methods to assure that the criteria of this standard are met, and are consistent with the GM Joining and Dispense Process Control Procedure (GMW15563). 5 Notes 5.1 Glossary. Crack: A crack is a type of fracture discontinuity characterized by a sharp tip a
40、nd high ratio of length to width of opening displacement on the exterior surface. Dimple: See Embossed Projection. Distortion: Distortion is a condition where the metal on either side of the projection weld is subjected to angular deformation (either by projection dies or welding electrodes that are
41、 not oriented perpendicular to the sheet surface). Embossed Projection: An embossed projection is a raised protrusion or dimple in sheet-metal produced by mechanical force using a punch to displace material into a cavity (die). See Figure 4. Figure 4: Embossed Projection Copyright General Motors Com
42、pany Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16435 Copyright 2013 General Motors Company All Rights Reserved February 2013 Page 5 of 7 Embossed Projection Diamete
43、r: The diameter of a spherical projection or the width of a linear embossed projection measured on the punch side of the embossed sheet. See Figure 5. Figure 5: Embossed Projection Diameter Evidence of Welding: Evidence of welding exists when a projection weld that is destructively tested tears mate
44、rial from either sheet being welded. Indentation: Indentation is the unintentional depression on the sheet surfaces caused by the welding electrodes or projection dies. (The intentional projection is not indentation.) Linear Projection Weld: A linear or elongated projection weld is a projection weld
45、 that has an embossed projection with a plane of symmetry running the length of the projection. See Figure 6. Figure 6: Linear Projection Example Product Quality Standard (PQS): Measurable requirements for product characteristics, which when satisfied ensure the product meets internal and external c
46、ustomer requirements. Original Qualified Setup: Original qualified setup is the set of projection and welding parameters that were established and documented during validation of the welding process. Spherical Projection Weld: A spherical projection is an axis-symmetric (dome-shaped) embossed projec
47、tion. Surface Marking: Visible eruptions, indentations, scratches, dents, whiskers, or other visual blemishes on the surface are referred to as surface marking. (The embossed projection imprint is not a surface mark.) Weldable Length: The weldable length for a linear projection weld is the length of
48、 the flat contact area of the embossed projection. See Figure 7. Figure 7: Linear Projection Weld Weldable Length Example Weld Button: A weld button or plug is that part of the weld that tears out in a peel or destructive chisel test. Weld Design Document: A product document that describes welding r
49、equirements such as number of welds, location of welds, applicable weld standards, weld patterns, weld notes, etc. 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 GMW16435 Copyright 2013 General Motors Company All Rights Reserved F
