1、WORLDWIDEENGINEERINGSTANDARDSMaterial Specification GMW16819Vehicle Suspension U-Bolt Coating Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Originating Department: North American Engineering Standards Page 1 of 41 Scope1.1 Material Description. This specification covers the m
2、aterials and performance requirements for a blackwaterborne organic coating over a zinc phosphate surface. The coating is specified for vehicle suspensionU-Bolt applications where ultraviolet (UV) resistance is not required.1.2 Symbols. Not applicable1.3 Typical Applications. Vehicle Suspension U-Bo
3、lt.2 ReferencesNote: Only the latest approved standards are applicable unless otherwise specified.2.1 External Standards/Specifications.ANSI B18.18.2M2.2 GM Standards/Specifications.GM9733P GMW3286 GMW15272GMW3059 GMW14872 GMW165512.3 Additional References.x TMC003 Material Safety Data Sheet guidanc
4、e documents (available at ).x General Motors Part Number 11502646x General Motors Part Number 11516092x General Motors Part Number 115161073 Requirements3.1 Requirements on Test Specimens. Not applicable.3.2 Production Coated Parts. Specific material requirements and appropriate test methods are lis
5、ted under3.4 and 3.5. These requirements shall be determined by tests performed on production parts coated on theproduction line.3.3 Critical Surfaces and Cure. The requirements listed in 3.4 and 3.5, shall be met on all critical surfacesafter coating application, cure and 30 minutes at room tempera
6、ture.3.4 Physical Properties.3.4.1 Cleaning.3.4.1.1 The use of mineral acids, such as hydrochloric acid, is not allowed. Diluted citric acid cleaners may beused to remove process oils.3.4.1.2 Rust preventatives which are used to prevent corrosion during shipment of the bare U-Bolt to the paintapplic
7、ator must be capable of being completely removed by the cleaning systems in use.3.4.2 Zinc Phosphating.3.4.2.1 Zinc Phosphate Coating Weight. The zinc phosphate shall have a coating weight of 27.5 g/m2minimum as tested per GM9733P. The test shall be conducted on a section of the U-Bolt or test panel
8、.3.4.2.2 Uniformity. The coating shall be uniform and with 100% coverage, visual estimation, over the surfaceof the U-Bolt.Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM W
9、ORLDWIDE ENGINEERING STANDARDS GMW16819 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 2 of 43.4.2.3 Zinc Phosphate Processing. Application of the zinc phosphate coating may be made according to theparameters set forth by the zinc phosphate supplier.3.4.3 Organic Coating.
10、3.4.3.1 The organic coating shall be uniform and continuous with no evidence of voids, craters, sags, run out,blisters, or other surface defects when visually examined.3.4.3.2 The color shall be black.3.4.3.3 Application. Application may be made by the dip spin or dip drain process.3.5 Performance R
11、equirements. The coated U-Bolt shall meet the performance requirements defined inTable1.Table 1: Performance RequirementsThickness Salt Spray per GMW3286 Red Rust8 microns minimum Note 1 600 h 5% Visual EstimationNote 1: Coating thickness to be measured on the non-threaded section of the U-Bolt leg.
12、3.5.1 Coating Rub Off. Coated parts should be dry to touch and not exhibit softening, swelling or change inadhesion when a coated part is rubbed ten (10) times with a clean, dry cloth using only the weight of thecoated part to supply pressure. Some minor rub-off onto the cloth is allowed.3.5.2 Salt
13、Spray Resistance. Parts coated to this specification shall be capable of withstanding the neutralsalt spray (NSS) test requirements listed in Table 1 when tested per GMW3286. Parts shall not show anyblistering after NSS testing. Evaluation shall be performed on the unthreaded areas of the fastener.3
14、.5.2.1 For initial approval, the parts must be tested per GMW3286 to meet the corrosion resistancerequirements when sampled per ANSI B18.18.2M.3.5.2.2 Normal production processes that are in statistical process control shall yield parts that are capable ofmeeting the salt spray requirements.3.5.2.3
15、A periodic NSS test of the parts being processed on each production line running this coating shouldbe conducted per Table B, Appendix I from ANSI B18.18.2M. The sample size shall be three (3) piecesminimum per line, per shift.3.5.2.4 Process control checks are to be made and recorded according to t
16、he coating manufacturersinstructions.3.5.3 Initial Source Qualification. For initial source qualification only, a production U-Bolt shall be subjectedto cyclic corrosion per GMW14872, (underbody, All, four (4) salt sprays, Method 1/2, Exposure A). The U-Boltshall be capable of meeting a rating of se
17、ven (7) or higher as defined in GMW15272, for a low/medium visibilitycomponent.3.6 Fastener Requirements.3.6.1 When applied to threaded products, the coating shall not have an adverse effect on normal installationand removal practices.3.6.2 The maximum thickness of coating which may be applied to th
18、reads on threaded products is limited bythe basic thread size (tolerance h or H). After coating, parts must gage with the appropriate basic size of a GOthread gage per GMW16551. Threads may be produced undersize/oversize (before coating) to accommodatethe coating thickness, providing the finished pr
19、oduct (after coating) meets all specified mechanical properties.Where mechanical properties are not specified, undersizing/oversizing is subject to approval by pertinentengineer, and all undersize/oversize shall be within permissible limits as agreed upon between the producerand the purchaser.3.6.3
20、Torque/tension testing shall be performed as follows:3.6.3.1 Regardless of U-Bolt thread size, coat a surrogate bolt, PN 11516107.3.6.3.2 The test washer shall be PN 11502646, and the test nut shall be PN 11516092.3.6.3.3 A tension test fixture with a load cell shall hold the test nut, bolt and wash
21、er, and measure the tensionproduced by tightening the bolt.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 GMW16819 Copyright 2012 General M
22、otors Company All Rights ReservedOctober 2012 Page 3 of 43.6.3.4 The load cell shall have a full scale accuracy of 0.5%.Test bolts shall be driven using a fixtured directcurrent (DC) electric nut runner. The nut runner shall have a capability for producing torques greater than thespecified torque ra
23、nge and shall be run at a continuous speed of 100 rpm 10 rpm.3.6.3.5 The socket cannot contact the test washer during test. The six (6) standard deviation (six sigma) torquerange must be within 92 Nm to 144 Nm at 56.1 kN tension.3.6.3.6 The tests shall be frequently run to maintain statistical quali
24、ty control. The test results shall be regularlyplotted and maintained in file to be submitted when required.3.7 Process Requirements. Significant changes in processing as determined by GM Engineering requirevalidation approval prior to implementation into production.3.7.1 Handling. Prior to painting
25、, U-Bolts must be stored under conditions that would not contribute todeterioration of the surface condition or the ability to provide optimum painting conditions.3.7.2 Curing. Cure temperatures are ambient to 104 C part metal temperature.3.7.3 Repairs. Coated U-Bolts may not be repaired without pri
26、or approval by the responsible GM FastenerEngineer.4 Manufacturing ProcessNot Applicable5 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 Eng
27、lish and domestic language, the English language shalltake precedence.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
28、 department prior to commencement of delivery of bulk supplies.A new 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 th
29、e responsibility of the supplier to inform the customer in a timely 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
30、prior tocommencement of delivery of non-conforming bulk supplies. In individual cases, a shorter test can be agreedto between the responsible Engineering department and the supplier.5.4 Material Safety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when achange in chemica
31、l composition of an existing product has occurred, a complete copy of the 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 a
32、ddition, product MSDS/SDS submissions must be in compliance with specific 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 Su
33、bstances for Parts.6 Approved SourcesMaterials supplied to this specification must be approved by General Motors.A list of approved materials can be found in MATSPC. This GM Material File is provided to third parties toreduce redundant testing of materials. If approved material already listed is use
34、d, the part supplier can use GMMaterial File reference for Production Part Approval Process (PPAP) material approval. If the decision is madeto use a not yet approved material, contact the Chassis Fastening Global Subsystem Leadership Team fordetail on the approval process. The material approval pro
35、cess must be completed prior to PPAP start date ofthe part supplied to General Motors.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 GMW168
36、19 Copyright 2012 General Motors Company All Rights ReservedOctober 2012 Page 4 of 47 Notes7.1 Glossary.MATSPC: Global repository of GM Approved Materials for corresponding GM Engineering Standards.7.2 Acronyms, Abbreviations, and Symbols.ANSI American National Standards InstituteDC Direct CurrentGH
37、S Globally Harmonized System of Classification and Labeling of ChemicalsMSDS Material Safety Data SheetNSS Neutral Salt SprayPN Part NumberPPAP Production Part Approval ProcessSDS Safety Data SheetUV Ultraviolet8 Coding SystemThis standard shall be referenced in other documents, drawings, etc., as f
38、ollows:U-Bolt Coating per GMW168199 Release and RevisionsThis standard was originated in June 2012. It was first approved by the Chassis Fastening Global SubsystemLeadership Team in October 2012. It was first published in October 2012.Issue Publication Date Description (Organization)1 OCT 2012 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-,-,-
