1、 WORLDWIDE ENGINEERING STANDARDS Material Specification GMW16431 Stainless Steel Fastener Coating Copyright 2012 General Motors Company All Rights Reserved January 2012 Originating Department: North American Engineering Standards Page 1 of 5 1 Scope This standard covers the performance requirements
2、for a high wear resistant, low friction coating. The coating is not intended to provide corrosion protection. 1.1 Material Description. The coating is a dip-spin or spray type coating which provides anti-seizing and controlled frictional properties. This coating process does not generate hydrogen; h
3、owever, pre-treatment processes, i.e., acid pickling could cause hydrogen adsorption. 1.2 Symbols. Not applicable. 1.3 Typical Applications. This coating is suitable for stainless steel externally and internally threaded parts (size greater than or equal to M6), particularly those with a prevailing
4、torque feature in the thread. 1.4 Remarks. 1.4.1 Tin (Sn) may negatively affect the corrosion performance of stainless steel. The coating may not contain measurable amounts of tin. 1.4.2 This coating is intended to control friction and prevent galling. However, not every type of material and interfa
5、ce was tested. It is recommended that Fastening and Materials Engineering be consulted for new applications. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. ASTM D2625-94 SAE J403 ISO 16047 SAE J404 2.2 GM Standa
6、rds/Specifications. GMW3059 2.3 Additional References. TMC003 Material Safety Data Sheet guidance documents (available at ). “Approved Finishers List“ file (available at ). Part No. 11612104, stainless steel bolt Part No. 11612105, stainless steel nut Part No. 11612106, stainless steel square washer
7、 3 Requirements 3.1 Coefficient of Friction. The coefficient of friction of the coated parts shall be 0.10 0.03 when measured per 3.1.1. Specific requirements for Production Part Approval Process (PPAP) and new chemical/applicator approval are described in 3.1.2 and 3.1.3, respectively. Note: Coeffi
8、cient of friction testing per 3.1.1 shall be performed regularly by the supplier (coating applicator or fastener supplier) as part of their process control plan. 3.1.1 After coating, the fastener total friction (tot) shall be 0.10 0.03 when tested according to ISO 16047, with the following additiona
9、l requirements: Use test washer per ISO 16047 type HL with plain surface, uncoated and degreased. Stamped identification is not allowed on the washer surface. Test nuts shall be plain surface, uncoated and degreased. For referee purposes, coefficient of friction testing shall be performed after a mi
10、nimum of 24 h after coating. Test nut and washer must be cleaned ultrasonically in acetone or a similar degreaser within 2 h of test. After tightening, there shall be a minimum of two full threads outside of the nut and a minimum of one full thread from the maximum grip gauging length. Tightening sp
11、eed shall be 30 3 rpm. 3.1.2 PPAP Requirements. If the production coated part cannot be tested as described in 3.1.1 due to small size or design (studs, lock threads, etc.), use GM bolt part number 11612104 (M10x1.5 stainless steel bolt). Describe in the PPAP report which coated fastener was used. T
12、he coefficient of friction 3 sigma values based on 10 samples are required to be within 0.10 0.03. 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 STA
13、NDARDS GMW16431 Copyright 2012 General Motors Company All Rights Reserved January 2012 Page 2 of 5 3.1.3 New Chemical and Applicator Approval Requirements. Apply coating to GM bolt part number 11612104 and test according to 3.1.1. The bolt is the driven part. Use test washer GM part number 11612106
14、(stainless steel) and test nut GM part number 11612105. The coefficient of friction 3 sigma values based on 30 samples are required to be within 0.10 0.03. 3.2 High Pressure Wear Characteristic. The minimum time to failure of 4 samples shall be greater than 3 minutes with the load maintained at 4450
15、 N (1000 lbf) per ASTM D2625-94 (2010), Procedure A with the test parameters described as follows (see Appendix A for figures of the fixture): Test Parameters: Speed of rotation: 290 3 rpm. Ambient temperature: 22 C 2 C. Step 1: 1330 N for 3 minutes. Step 2: 2220 N for 1 minute. Step 3: 3330 N for 1
16、 minute. Step 4: 4450 N until failure. Test Specimens: Pin Material: 3135 steel per SAE J404. Pin Finish 13 to 25 m rms. Pint Hardness: 87 to 91 HRb. Vee Block Material: 1137 steel per SAE J403. Vee Block Finish: 13 to 25 m rms. Vee Block Hardness: 20 to 24 HRc. Note: This test is for new chemical a
17、pproval only. 4 Manufacturing Process The GM-approved process, including pre-treatment (cleaning), coating, and post-treatment shall be performed by one company in one facility. The equipment, process controls, chemicals, and location used must remain the same for regular production. This includes p
18、re-treatment (such as cleaning) and post treatment. These operations cannot deviate without prior approval by GM. For PPAP and each production lot of coated parts, the applicator shall supply a certificate to their customer with the following information: This specification number. Applicator name a
19、nd address. Coating system used. Part number. Date(s) the parts were coated. Coefficient of friction of coating at PPAP. Coefficient of friction as per most recent process control test. The applicator shall keep the certificates for a minimum of 5 years. 5 Rules and Regulations 5.1 Legal Regulations
20、. All materials must satisfy applicable laws, rules, regulations and recommendations valid in the country of usage. 5.2 Language. In the event of conflict between the English and domestic language, the English language shall take precedence. 5.3 Inspection and Rejection. Samples of components or mat
21、erials released to a GM material specification shall be tested for conformity with the requirements of this material specification and approved by the responsible Engineering department prior to commencement of delivery of bulk supplies. A new approval must be received for any changes, e.g., propert
22、ies, manufacturing process, location of manufacture, etc. If not otherwise agreed, all testing and documentation normally required for initial release must be completed. It is the responsibility of the supplier to inform the customer in a timely manner, without solicitation, and to include documenta
23、tion 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 to commencement of delivery of non-conforming bulk supplies. In individual cases, a shorter test can be agreed to
24、between the responsible Engineering department and the supplier. 5.4 Initial Source Approval. No shipments shall be made by any supplier until representative initial production samples have been approved by the appropriate Materials Engineering department(s) as meeting the requirements of this speci
25、fication. 5.5 Material Safety Data Sheets/Safety Data Sheets (MSDS/SDS). For new product submissions, or when a change in chemical composition of an existing product has occurred, a complete copy of the Material Safety Data Sheet/Safety Data Sheet must be submitted in compliance with the Globally Ha
26、rmonized System of Classification and Labeling of Chemicals (GHS) requirements or other country-specific MSDS/SDS requirements. In addition, product MSDS/SDS submissions must be in compliance with specific country General Motors TMC003 Material Safety Data Sheet/Safety Data Sheet guidance documents
27、where available. 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 GMW16431 Copyright 2012 General Motors Company All Rights Reserved January
28、2012 Page 3 of 5 5.6 All materials supplied to this standard must comply with the requirements of GMW3059, Restricted and Reportable Substances for Parts. 6 Approved Sources Engineering qualifications of an approved source are required for this standard. Only sources listed in the GM Materials File,
29、 GM Supply Power, under this standard number have been qualified by Engineering as meeting the requirements of this standard. For other GM locations, the responsible Engineering group should be contacted to obtain the approved source in that individual country. GM-approved material and applicator mu
30、st be used. A list of approved materials and applicators can be found in in the file “Approved Finishers List“. 7 Notes 7.1 Glossary. Not applicable. 7.2 Acronyms, Abbreviations, and Symbols. m micrometer GHS Globally Harmonized System of Classification and Labeling of Chemicals GSSLT Global Subsys
31、tem Leadership Team HRb Rockwell B hardness number HRc Rockwell C hardness number lbf foot pounds MSDS Material Safety Data Sheet PPAP Product Part Approval Process rms roughness measurement system rpm revolutions per minute SDS Safety Data Sheet Sn Tin 8 Coding System This standard shall be referen
32、ced in other documents, drawings, etc., as follows: Material per GMW16431. 9 Release and Revisions This standard was originated in October 2010. It was first approved by the Finishes and Coatings Global Subsystem Leadership Team in January 2012. It was first published in January 2012. Issue Publicat
33、ion Date Description (Organization) 1 JAN 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-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16431 Copyright 2012
34、General Motors Company All Rights Reserved January 2012 Page 4 of 5 Appendix A Figure A1: ASTM D2625-94, Test Setup, Fixture Open Figure A2: ASTM D2625-94, Test Setup, Fixture Closed Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproducti
35、on or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16431 Copyright 2012 General Motors Company All Rights Reserved January 2012 Page 5 of 5 Figure A3: ASTM D2625-94, Graphical Representation Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
