1、WORLDWIDEENGINEERINGSTANDARDSMaterial Specification GMW15657Aluminum Forgings Copyright 2013 General Motors Company All Rights ReservedJune 2013 Page 1 of 71 ScopeThis material standard covers forgings made of Aluminum alloys used in automotive and allied industries. Thisspecification specifies chem
2、ical composition and material properties based on test coupons excised fromforged components.1.1 Material Description. The materials are aluminum alloys of Aluminum Association (AA) 6000 series andsome vendor specific alloys similar to 6000 series.1.2 Symbols. Not applicable.1.3 Typical Applications
3、. Aluminum alloy forging applications are many in most vehicle systems. Majorapplications are chassis components such as control arms, links, knuckles, brackets, yokes, etc.2 ReferencesNote: Only the latest approved standards are applicable unless otherwise specified.2.1 External Standards/Specifica
4、tions.ASTM B557 ASTM E10 ISO 209 ISO 6892ASTM B918/B807 ASTM G47 ISO 6506 ISO 164552.2 GM Standards/Specifications.GMW3059 GMW16704 GMW167052.3 Additional References.x Aluminum Association (AA)x TMC003 Material Safety Data Sheet guidance documents (available at ).3 Requirements3.1 Chemical Requireme
5、nts.3.1.1 Forgings furnished to this specification shall conform to the composition limits shown in Table 1.3.1.2 To meet the mechanical property requirements, it will be necessary to restrict chemical compositionranges of specific elements and must be approved by General Motors prior to Production
6、Part ApprovalProcess (PPAP). Selected ranges shall become the drawing requirements.3.1.3 Alloy designations and composition limits were obtained from Aluminum Association (AA) and ISO 209reference standards when available. Some are vendor specifications.3.1.4 Any chemical composition changes to GMW1
7、5657 alloy grades shall be shown on the engineeringdrawing.3.2 Mechanical Requirements.3.2.1 Tensile test specimens shall be excised from a part location specified on the engineering drawing.3.2.2 The test specimen axis shall be oriented as parallel to major wrought direction of maximum metal flow.3
8、.2.3 Required tensile properties determined from heat treated forged parts are given in Table 2.3.2.4 The engineering drawing may specify property requirements of alternate specimens that are not parallelto maximum metal flow.Copyright General Motors Company Provided by IHS under license with Genera
9、l Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15657 Copyright 2013 General Motors Company All Rights ReservedJune 2013 Page 2 of 73.2.5 The tension tests shall be made in accordance with test methods ISO 6892,
10、 GMW16705 and alternatelyASTM B557.3.2.6 Hardness testing shall be done in accordance with ISO 6506, GMW16705 and alternately ASTM E10.3.2.7 A test plan shall be established upon mutual agreement between the seller and buyer, GMW16704 maybe used as guidance in setting up the test plan system.3.3 Phy
11、sical Requirements. Typical physical properties associated with each alloy grade are shown inAppendix A, Table A1.3.4 Additional Requirements.3.4.1 Microstructural Requirements. The stronger linear fibrous structure in the die forging process helps toimprove the mechanical properties. The aim is to
12、maintain the fibrous structure as much as possible andminimize recrystallized structure.3.4.2 Forging Requirements.3.4.2.1 Forgings furnished shall be of uniform quality and free from surface anomalies such as seams, laps,bursts, lubricants, dust and dirt, and quench cracks, all to an extent that wo
13、uld be detrimental to safe handling,machinability, appearance or performance.3.4.2.2 Cracks and crack-like anomalies are not permitted.3.4.2.3 Any anomalies, plus surface roughness and forging cleanliness may have maximum allowable limitsspecified.3.4.2.4 For any of the above forging requirements, a
14、 measurement system shall be agreed upon betweenpurchaser and supplier.3.4.3 Stress Corrosion Resistance. Stress Corrosion Cracking (SCC) is caused by sustained tensile stressunder some service environments. For example:x Corrosive environment which could result in premature failure of parts along g
15、rain boundaries.x Varying amounts of copper in the alloy influence SCC differently.x Alloys containing higher percentage of copper and silicon in excess of stoichiometric magnesium silicide(Mg2Si) are relatively more prone to SCC. Short transverse direction in forging is more prone to SCC thanothers
16、.x Fine grains minimize SCC. Microstructural differences among various heat treatments in the form of sizeand type of precipitates at the grain boundaries could also be a factor.Hence, alloy percentages in materials, fabricating methodologies, heat treatment methods, loading paths, etc.,shall be car
17、efully selected to minimize SCC so as to meet the durability requirements of components. Stresscorrosion testing may be performed per test method ISO 16455 or ASTM G47.Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networkin
18、g permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW15657 Copyright 2013 General Motors Company All Rights ReservedJune 2013 Page 3 of 7Table 1: Chemical Composition Limits in percent (%) by Mass for Aluminum Forging Alloys Remainderof Alloy is AluminumGMW Grades Elements
19、percent (%) by MassGMW15657M-AL-F- Silicon Iron Copper Manganese MagnesiumMg1SiCu(6061) Note 1 0.40 to 0.80 0.70 maximum 0.15 to 0.40 0.15 maximum 0.80 to 1.20Si1MgMn(6082) 0.70 to 1.30 0.50 maximum 0.10 maximum 0.40 to 1.00 0.60 to 1.20Si1MgCuMn 0.85 to 0.95 0.20 maximum 0.45 to 0.55 0.45 to 0.50 0
20、.75 to 0.85Si1Mg1MnCu 0.95 to 1.15 0.30 maximum 0.20 to 0.50 0.40 to 0.55 0.85 to 1.10GMW Grades Elements Percent (%) by Mass Other Note 2GMW15657M-AL-F- Chromium Zinc Titanium Zirconium Each TotalMg1SiCu(6061) Note 1 0.04 to 0.35 0.25maximum 0.15 maximum - 0.05 0.15Si1MgMn(6082) 0.25 maximum 0.20ma
21、ximum 0.10 maximum - 0.05 0.15Si1MgCuMn 0.17 to 0.24 0.05maximum 0.02 to 0.04 0.04 maximum 0.05 0.15Si1Mg1MnCu 0.10 to 0.20 0.25maximum 0.10 maximum 0.05 maximum 0.05 0.15Note 1: First part of alloy call out follows ISO form at. The second part is AA alloy designation when available.Note 2: Residual
22、s are similar to AA specification guidelines.Table 2: Minimum Mechanical Properties at +584 mm 127 mm (+23 in 5 in) Test Coupons Excised inthe Direction of Grain Flow from Forged Parts After T6 Heat TreatmentGMW15657M-AL-F-TensileStrengthMPaYieldStrengthMPaElongationPercent (%)BrinellHardnessHBWYoun
23、gsModulusGPa Note 1PoissonsRatio Note 1Mg1SiCu(6061) -T6 310 270 10 95 69 0.33Si1MgMn(6082)-T6 340 310 10 95 70 0.33Si1MgCuMn-T6 360 330 10 105 70 0.33Si1Mg1MnCu-T6 370 345 10 104 70 0.33Note 1: Youngs modulus and Poissons ratio given in this table are for information only; these properties are not
24、subject to minimumrequirements.4 Manufacturing Process4.1 Forging. Forgings shall be done with closed dies, conventional (flash) die forging or flash-free die forging.Aluminum does not flow readily, even at high pressure, under forging temperatures. As a result, forgings usedin automotive applicatio
25、ns may require multiple hits/dies. A bending or roll forming operation may also beneeded. The dies are usually heated and appropriate lubricants are used for ease of material flow in the dieand release of the part from the die.4.1.1 Starting stock for automotive parts is generally extruded round bar
26、. Other extruded shapes can also beutilized depending upon the part configuration and the number of parts to be produced. The extruded bar isalready fully wrought ensuring that the final forging will have maximum grain refinement and free of anyporosity or residual cast structure. This contributes f
27、or improved mechanical properties.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 GMW15657 Copyright 2013 General Motors Company All Rights
28、ReservedJune 2013 Page 4 of 74.1.2 Cast stock of continuously cast chilled bars may also be used upon approval by GM MaterialsEngineering. Care must be taken to select the appropriate forge press tonnage since the advantage of orientedgrain flow and dense grain structure with extruded bar is absent
29、with cast stock. Sufficient metal movementduring forging operations is necessary to rearrange cast grain structure for optimum mechanical properties.4.1.3 The billet castings used for extrusion shall be free of anomalies detrimental to forging. The continuouslycast bars forged as cast shall be peele
30、d to remove surface anomalies. All billet castings used for extrusion orcast bars directly used in forgings shall be ultrasonically tested to verify absence of internal cracks. In addition,they are homogenized by heating to appropriate temperature and time to eliminate any segregation of alloyingele
31、ments during the casting process that may impede enhanced mechanical properties. Any deviation from theabove requirements shall be approved by GM Materials Engineering.4.1.4 Parts may require handwork, such as grinding in between forging steps to eliminate surfaceimperfections which could be forged
32、into the part during subsequent forging steps.4.2 Heat Treatment. Forged parts are usually supplied with T6 heat treatment. T6 involves solution heat-treatment, quenching in appropriate media to minimize distortion and precipitation hardening (artificial aging).Some forgings may distort during quenc
33、h. It may be necessary to straighten these parts before the agingcycle. The heat treatment shall be in accordance with practice ASTM B918/B807.Note: Upon approval from GM materials engineering, a separate solution heat-treatment may not be carriedout. Instead, when the part is heated to solution hea
34、t-treatment temperature (analogous to Extrusion PressSolution Heat Treatment for Aluminum Alloys ASTM B807) in the final die forging and quenched without anydelay, it may be accepted. The process must be highly automated and capability shall be proven. Controls areneeded to reject any part automatic
35、ally when the process control settings are out of range.4.3 Cleaning and Inspection.4.3.1 Forgings shall be crack free.4.3.2 To comply with this requirement, 100% fluorescent dye penetrant inspection may be specified.4.3.3 The parts must be etched to perform this inspection.4.3.4 For parts that are
36、not etched for subsequent penetrant inspection, if the cosmetic appearance is an issueon certain applications, appropriate methods shall be used to clean the die lubricant.4.3.5 Parts shall not be ground with a grinding wheel after the final forging step as grinding may smear thesurface anomalies be
37、fore this inspection.5 Rules and Regulations5.1 Legal Regulations. All materials must satisfy applicable laws, rules, regulations and recommendationsvalid in the country of usage.5.2 Language. In the event of conflict between the English and domestic language, the English language shalltake preceden
38、ce.5.3 Inspection and Rejection. Samples of components or materials released to a GM material specificationshall be tested for conformity with the requirements of this material specification and approved by theresponsible Engineering department prior to commencement of delivery of bulk supplies.A ne
39、w approval must be received for any changes, e.g., properties, manufacturing process, location ofmanufacture, etc. If not otherwise agreed, all testing and documentation normally required for initial releasemust be completed.It is the responsibility of the supplier to inform the customer in a timely
40、 manner, without solicitation, and toinclude documentation of all modifications of materials and/or processes and to apply for a new release.If not otherwise agreed, all release tests shall be repeated and documented by the supplier prior tocommencement of delivery of non-conforming bulk supplies. I
41、n individual cases, a shorter test can be agreedto between the responsible Engineering department and the supplier.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
42、 ENGINEERING STANDARDS GMW15657 Copyright 2013 General Motors Company All Rights ReservedJune 2013 Page 5 of 75.4 Material Safety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when achange in chemical composition of an existing product has occurred, a complete copy of th
43、e Material SafetyData Sheet/Safety Data Sheet must be submitted in compliance with the Globally Harmonized System ofClassification and Labeling of Chemicals (GHS) requirements or other country-specific MSDS/SDSrequirements. In addition, product MSDS/SDS submissions must be in compliance with specifi
44、c countryGeneral Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents where available.5.5 All materials supplied to this standard must comply with the requirements of GMW3059, Restricted andReportable Substances for Parts.6 Approved SourcesMaterials supplied to this specific
45、ation must be approved by General Motors.The appropriate GM Materials Engineering department(s) must confirm material as meeting the requirementsof this specification. Any test data sheets of material submitted to General Motors for such confirmation (e.g.,during Production Part Approval Process (PP
46、AP) under this material specification must list all properties andmust apply corresponding test methods of this material specification.7 Notes7.1 Glossary.MATSPC: Global repository of GM approved materials for corresponding GM Engineering Standards.7.2 Acronyms, Abbreviations, and Symbols.AA Aluminu
47、m AssociationASTM ASTM InternationalGHS Globally Harmonized System of Classification and Labeling of ChemicalsHBW Brinell HardnessMg2Si Magnesium SilicideMSDS Material Safety Data SheetPPAP Production Part Approval ProcessSCC Stress Corrosion CrackingSDS Safety Data Sheet8 Coding SystemThis standard
48、 shall be referenced in other documents, drawings, etc., as follows:Material per GMW15657Example: GMW15657M-AL-F-Mg1SiCu(xxxx)-T6Where:GMW GM Worldwide15657 Sequential NumberM Material Type - MetalAL CategoryF Subcategory - Primary forming method - ForgingMg1SiCu Alloy callout per ISO format (See Ta
49、ble 1)(xxxx) AA Alloy origination cross reference when available (see Table 1)T6 Heat TreatmentCopyright 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 GMW15657 Copyright 2013 General Motors Company All Rights ReservedJune 2013 Page 6 of 79 Release and Revisi
