1、EUROPEENGINEERINGSTANDARDSGeneral Specification GME17400Welding of Rear Seat Metal Structures Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 1 of 171 IntroductionNote: Nothing in this standard supercedes applicable laws and regulations.Note: In the event of conflict betwe
2、en the English and domestic language, the English language shall takeprecedence.1.1 Purpose. This standard describes the general requirements, designs and tests concerning laser-weldedjoints where 2- and 3- pieces of sheet metal are joined and contains general information to the design of a laser-we
3、lded joint in case where detailed information is not stated on the drawings.Metallurgical aspects, e.g. grain size and hard-ness, are not considered.The criteria established in this standard become mandatory when referenced on a weld design document.Deviations from any weld criteria provided in this
4、 standard shall be identified on a weld design document.1.2 Applicability. This standard is applicable to laser stainless steels and high strength low alloy (HSLA) steelswith a carbon content of 25 % of the Welded Seam Length LsFigure 7: Stiffness CalculationGM EUROPE ENGINEERING STANDARDS GME17400
5、Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 6 of 17Figure 8: Measurement of Seam Widtha Seam width4.4.3.1.1 With Material Thicknesses at the Ratio of 1:3. In welded joints the minimum penetration depth ise 1 x t1. “t1” represents the thickness of the thinner piece of s
6、heet metal (see Figure 9).Figure 9: Ratio of Material Thicknesses 1:34.4.3.1.2 With Material Thicknesses at the Ratio of 1:3. It is advisable that the welding seam go throughthe welding components completely (Weld through). With a following visual check the complete penetration ofthe welding seam sh
7、all be optically checked on the opposite side of the welding direction (see Figure 10).Figure 10: Ratio of Material Thicknesses 1:34.4.3.2 Seam Length.4.4.3.2.1 Length of the Weld Surface LS. The length of the weld which is measured on the surface of the sheetmetal is designated the seam length LS.
8、The measure LS shall be within the dimension specified on the drawing(see Figure 11).GM EUROPE ENGINEERING STANDARDS GME17400 Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 7 of 17Figure 11: Length of Weld Surface LS / Fusion Length LF4.4.3.2.2 Fusion Length LF. Length of
9、 seam measured on the contact surface less all the internal seam faultsis designated the LF (see Figure 11).4.4.3.3 Weld Seam Position. The position of the weld seam shall correspond to drawing specifications.The following values shall be considered as position and dimensional tolerances. Unless oth
10、erwise specified onthe drawing the weld position of measures X and/or Y can vary 1.5 mm from the table (see Figure 13). Thisvalue does not cover the tolerance of the components (see Figure 12).Figure 12: Weld Seam PositionFigure 13: Example for the Table of Drawing4.4.4 Irregularities in the Welded
11、Seam. If not otherwise specified on the drawing, over a length of:30 % of the sheet metalthickness, edge notches, surface porosity and weld overfill 20 % of the sheet metal thickness are designatedexternal welded seam irregularities.Figure 18: Example of Sum for External Faults4.4.6.1 Root Concavity
12、 (Weld Surface Concavity). In root concavity the weld underbead has a concave shape(see Figure 19).Limit values:h3/4 0.5 x tmint 0,7mmh3/4 0.35 x tmint = 0.7 mm to 1.0 mmh3/4 0.3 x tmint 1.0 mmGM EUROPE ENGINEERING STANDARDS GME17400 Copyright 2015 General Motors Company All Rights ReservedOctober 2
13、015 Page 10 of 17Figure 19: Weld Surface Concavity; Root Concavityh3 Weld surface concavityh4 Root concavity4.4.6.2 Edge Notches. The transition between the weld surface and the workpiece surface is interrupted bylongitudinal grooves at the side (see Figure 20).GM EUROPE ENGINEERING STANDARDS GME174
14、00 Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 11 of 17Figure 20: Edge Notches and Example of Sum for Internal and External FaultsA UnderfillingB Edge notch4.4.6.3 Weld Spatter. Melt can be thrown out, e.g. as a consequence of a too small joint gap. The extent towhich
15、weld spatter shall be removed is dependent on the position of the component. Corresponding modes ofprocedure shall be regulated in a work instruction (see Figure 21).GM EUROPE ENGINEERING STANDARDS GME17400 Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 12 of 17Figure 21:
16、 Schematic Diagram of Weld Spatter4.4.6.4 Weld Overfill, Root Overfill. In weld overfill the top bead of the weld has a convex shape. In root overfillthe weld root has a convex shape.The maximum permissible limit values for weld overfill and root overfill (see Figure 22) are:h1/2 0.5 x tmint 0.7 mmh
17、1/2 0.35 x tmint = 0.7 mm to 1.0 mmh1/2 0.2 x tmint 1.0 mmFigure 22: Weld Overfill, Root Overfillh1 Weld overfillh2 Root overfill4.4.6.5 Holes. If holes are present, the reference in paragraph 1 about the requirements regardingwatertightness shall be noted.4.4.6.6 Surface Porosity. Discontinuous dep
18、ressions are designated surface porosity (see Figure 23).These defects require the welding parameters to be optimised. Whether porosities are generally permitted canbe specified on the drawing.GM EUROPE ENGINEERING STANDARDS GME17400 Copyright 2015 General Motors Company All Rights ReservedOctober 2
19、015 Page 13 of 17Figure 23: Surface Porosity1 Surface porosity4.5 Quality Assurance Measure and Test Plan.4.5.1 Welded Seam Test. Destructive test on laser-welded seam for quality assurance and to guaranteedurability. Metallurgical investigations of the welded seam are necessary because destructive
20、tests lead to failurein the base material in many cases but faults inside the welded seam cannot be detected. Otherwise non-destructive tests shall be used. (e.g. X-ray, thermography)4.5.2 Testing laser-welded joints shall be performed by trained personnel.Execution and the working procedure shall b
21、e listed in the corresponding work instructions.4.5.3 The tests shall be performed at specified intervals. In principle, these tests shall be performed at start ofpilot production (if pilot and original equipment are present), before SSV (Start Saleable Vehicles) to decide onthe parameters for all t
22、he welds permanently.4.5.4 The tests shall be performed if changes or repairs are undertaken to the laser-welding system or if robotsor equipment components are replaced or repaired. In addition, these shall be performed after all parameterchanges at specified intervals from the start until a decisi
23、on is taken on the intervals.4.5.5 The welds in “critical operations” shall be tested according to the guideline on Critical Operations (D-01).4.5.6 Example for Control plan. For the fulfillment of the quality of laser welding seams on seat structures (seeFigure 24).GM EUROPE ENGINEERING STANDARDS G
24、ME17400 Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 14 of 17Figure 24: Example for Control Plan4.6 General Requirements.4.6.1 Sheet Metal Thickness. Welding in shall preferably be performed from the thinner sheet into the thickerone.Triple overlaps between sheets of me
25、tal in the laser-welded area shall be avoided.4.7 Tests.4.7.1 Non-Destructive Testing.4.7.1.1 100 % test with a process control system.4.7.1.2 100 % visual test if there is an indication of faults from process control.4.7.1.3 Seam Monitoring. During the welding process the inline monitoring systems
26、can supervise the backreflection for instance for YAG-Laser. When over or falling below the limits by disturbances the parts shall beremoved and done over again if necessary and/or the limits or welding attitude shall be corrected (see Figure 25).GM EUROPE ENGINEERING STANDARDS GME17400 Copyright 20
27、15 General Motors Company All Rights ReservedOctober 2015 Page 15 of 17Figure 25: Seam Monitoring only for Nd:YAG-Laser4.7.1.3 100 % visual test if there is an indication of faults from process control.4.7.1.4 Chisel Test according to ISO 10447. The chisel is driven between the welded parts next to
28、the welduntil the material becomes deformed and this bends sharply at the laser-welded seam.The test is completed when unbuttoning commences without a fracture or tear in the weld.If the test reveals a sufficient quality, the components are reshaped to their original shape.If a fracture occurs betwe
29、en the pieces of sheet metal (without unbuttoning), then a non-durable, unacceptableweld bond is present.The direction of the fracture load shall normally be specified on the part drawing. If no data is present on thedrawing, the direction of the fracture load is at the testers discretion.Unbutton t
30、ests shall be performed on several bodies, starting with the first weld. If the correct welding parametershave been found and satisfactory, constant results are available, unbutton tests can be reduced step by step.4.7.2 Desctructive Testing.4.7.2.1 Micrographs. Cuts shall be performed on several pa
31、rts, starting with the first weld, so that micrographscan be produced. If the correct welding parameters have been found and satisfactory, constant results areavailable, the number of micrograph samples can be reduced.The supplier must guarantee the quality at any time and/or these requirements at t
32、he product according toGMW15563 guarantee and document accordingly. Example for the documentation of micrographs (seeFigure 26).4.7.3 Non Destructive Testing. To detect like cavities etc. x-ray or thermography can be used.GM EUROPE ENGINEERING STANDARDS GME17400 Copyright 2015 General Motors Company
33、 All Rights ReservedOctober 2015 Page 16 of 17Figure 26: Example Micrographs Documentation (Schlechte Kopie)a 0.9 x tminh1/2 0.2 x tmin (Weld overfill)h3/4 0.3 x tmin (Weld concavity)h 0.2 x tmin but 0.3 mm maximume 1 x tmin4.7.2.2 Unbutton Test. Unbutton tests shall be performed if fracture loading
34、 is present along the length, startingwith the first weld. Unbutton tests shall be performed on several parts at the start of production. If the correctwelding parameters have been determined and satisfactory, constant results are available (75 % minimum ofthe fracture surface in the material), the
35、number of unbutton tests can be reduced.5 Provisions for ShippingNot applicable.GM EUROPE ENGINEERING STANDARDS GME17400 Copyright 2015 General Motors Company All Rights ReservedOctober 2015 Page 17 of 176 Notes6.1 Glossary. Not applicable.6.2 Acronyms, Abbreviations, and Symbols. Not applicable.7 A
36、dditional Paragraphs7.1 All parts or systems supplied to this standard must comply with the requirements of GMW3059, Restrictedand Reportable Substances for Parts.7.2 Repair Requirements for Laser-Welded Seams.7.2.1 All structural laser welds, the execution of which does not correspond to paragraph
37、4.4.4 and/or 4.4.5.1,require repair measures.7.2.2 Defective structural laser welds shall be repaired as specified by the development department responsible.7.3 Rework. According to GMW15425, Appendix B and C.8 Coding SystemThis standard shall be referenced in other documents, drawings, etc., as follows:GME174009 Release and RevisionsThis standard was first approved and released in October 2015.Issue Publication Date Description (Organization)1 OCT 2015 Initial publication.(Metallurgy Fasteners Sealing Systems; Material & Presses and JoiningTechnology / GME Interior)
