1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev 01 2018 05 25 Revised See Summary of Revisions G. Weber, NA 2013 03 22 Released G. Weber, NA Controlled document at www.MATS Copyright 2018, Ford Global Technologies, LLC Page 1 of 7 FASTENER FINISH, ELECTROPLATED ZINC, TRIVALENT WSS-M21P
2、52-A1 CHROMIUM PASSIVATE, SILVER IRIDESCENT FASTENER FINISH, ELECTROPLATED ZINC, TRIVALENT WSS-M21P52-A2 CHROMIUM PASSIVATE, LUBRICATED TOPCOAT SEALER, SILVER FASTENER FINISH, MECHANICAL ZINC, TRIVALENT WSS-M21P52-A3 CHROMIUM PASSIVATE, LUBRICATED TOPCOAT SEALER, SILVER-GREY FASTENER FINISH, ELECTRO
3、PLATED ZINC, TRIVALENT WSS-M21P52-A4 CHROMIUM PASSIVATE, LUBRICATED TOPCOAT SEALER, ENHANCED LUBRICITY, SILVER 1. SCOPE The materials defined by these specifications are corrosion protective coatings over steel and iron substrates. All consist of electrolytic or non-electrolytic zinc plating with tr
4、ivalent chromium passivate. A2, A3 and A4 are also coated with a clear sealer to increase corrosion resistance and/or to provide consistent torque-tension control. 2. APPLICATION These specifications were released for materials used as corrosion protective coatings for fasteners and other standard p
5、arts used throughout the vehicle. Some of the processes used to produce these coatings may induce hydrogen embrittlement in parts with high hardness. Parts identified as being at risk for hydrogen embrittlement shall meet the requirements of WSS-M99A3-A. A1: Corrosion resistance for non-threaded fas
6、teners which subsequently receive an adhesive coating, and for non-threaded standard parts with lower corrosion requirements A2: Corrosion resistance plus lubrication for threaded fasteners A3: Corrosion resistance plus lubrication for threaded fasteners with high hardness and the risk of hydrogen e
7、mbrittlement A4: Corrosion resistance plus enhanced lubrication for threaded fasteners such as thread forming screws for metal 2.1 SERVICE APPLICATION 2.1.1 The recommended maximum continuous service temperature is 120C for optimal corrosion performance. 2.1.2 These coatings exhibit electrical conti
8、nuity to the substrate and may be used for electrical grounding fasteners in body-in-white or interior applications. 2.1.3 These coatings are effective for slowing galvanic corrosion associated with the use of steel fasteners in direct contact with aluminum components, or in indirect contact with ma
9、gnesium components. 2.1.4 These coatings are not recommended for high visibility applications, severe abrasion conditions or where chip resistance is required. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2018, Ford Global Technologies, LLC Page 2 of 7 3. REQUIREMENTS 3.1 APPROVED M
10、ATERIALS This specification requires the use of approved sources. Only the sources identified on the Ford Approved Source List (ASL) can be used when this specification is listed on the drawing, CAD file, or other documents. The list of approved sources is located within Ford at or available extern
11、ally through a Ford Materials Engineer. 3.2 EMBRITTLEMENT Parts coated to this specification shall be free from the detrimental effects of hydrogen embrittlement or other factors which result in part brittleness. All parts shall meet the requirements of WSS-M99A3-A. 3.3 COATING APPLICATION 3.3.1 App
12、licators shall follow material supplier procedures and recommendations for chemical usage, equipment, analysis, and processing. Applicators must have documentation to show that procedures and recommendations are being followed. 3.3.2 Part cleanliness prior to coating is critical in achieving optimal
13、 adhesion of the coating. The substrate shall be free of oil, dirt, and similar foreign materials. If a cleaning process is necessary, it shall have no detrimental effect on the substrate, including freedom from embrittlement. This is especially important for parts with hardness greater than HRC 35.
14、 See WSS-M99A3-A. 3.3.3 The sealers used under this specification do not require curing. The sealers shall be dried in place using hot air, typically in a spin dryer. Drying on a conveyer and other drying methods may be appropriate. 3.3.4 The applicator shall follow the material suppliers recommenda
15、tions concerning the drying temperature and spin speeds suitable for the basket diameter being used. 3.3.5 The temperatures associated with de-embrittlement heat treatments can cause degradation of the passivates and sealers. Parts with hardness greater than HRC 35, for example washers, requiring an
16、 electroplated finish should be passivated and sealed after de-embrittlement heat treatment. 3.4 COATING APPEARANCE 3.4.1 The finishes will be smooth, fine grained, adherent, and free from blisters, pits, nodules, indications of burning, and other defects. All details of workmanship shall conform to
17、 the best practice for high quality plating. 3.4.2 Parts coated to A1 will have a silver iridescent color, A2 and A4 will have a silver color, and A3 will have a silver-grey color. 3.4.3 The sealers used for A2, A3 and A4 will be a translucent film free from discontinuities. 3.4.4 The sealers used f
18、or A2, A3 and A4 have a UV light visible tracer. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2018, Ford Global Technologies, LLC Page 3 of 7 3.5 COATING PROPERTIES 3.5.1 Thickness (ASTM B659 / ASTM B487) 3.5.1.1 The zinc layer shall have a thickness of 8 to 14 micrometers measured
19、on flat surfaces. In case of dispute, the thickness measurement umpire method shall be metallographic sectioning per ASTM B487. 3.5.1.2 The passivate layer thickness is not subject to measurement but will be less than 500 nanometers and greater than 200 nanometers. 3.5.1.3 The sealer layer thickness
20、 is not subject to measurement but will be less than 2 micrometers and greater than 0.5 micrometers. The thickness shall be sufficient to meet the corrosion requirements of the substrate material as well as the friction requirements. 3.5.1.4 The typical overall thickness of these coatings is 10 to 1
21、2 micrometers. 3.5.2 Adhesion (ASTM B 571) The coating shall withstand normal handling, storage, and installation without flaking or peeling or other loss of adhesion. In addition, there shall be no blistering or flaking after baking for hydrogen de-embrittlement. Adhesion of the plating to the base
22、 metal must conform to the requirements of one of the following test methods per ASTM B 571 unless otherwise indicated. 3.5.2.1 Heat Quench Test There shall be no blistering or chipping of the finish after heating coated parts to 220 +/- 5C for 30 +/- 5 minutes and quenching in water at room tempera
23、ture. 3.5.2.2 Burnishing Test No blistering, lifting, or peeling of the finish from the substrate is permitted following the burnishing test. 3.5.3 Torque Tension Performance (WZ101, Test Program B, M10x1.5 PC 8.8 surrogate bolt, S437-coated nut, WX100 washer, 25.3 kN tension) When tested in accorda
24、nce with Ford Worldwide Fastener Standard WZ101, coated fasteners shall have a friction coefficient within +/- 0.03 of the nominal value below: WSS-M21P52-A2 0.15 WSS-M21P52-A3 0.15 WSS-M21P52-A4 0.08 ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2018, Ford Global Technologies, LLC P
25、age 4 of 7 3.6 RESISTANCE PROPERTIES 3.6.1 Laboratory Accelerated Cyclic Corrosion Test (CETP 00.00-L-467) Non-Ferrous Corrosion Ferrous Corrosion WSS-M21P52-A1 1 weeks 2 weeks WSS-M21P52-A2 2 weeks 4 weeks WSS-M21P52-A3 2 weeks 3 weeks WSS-M21P52-A4 2 weeks 4 weeks Testing shall be done on coated p
26、arts whenever possible (not panels). Parts for testing shall have no visible non-ferrous corrosion products at the beginning of testing. Parts shall be tested in vehicle orientation. Failure is constituted by evidence of corrosion products on surfaces directly visible in the application on the vehic
27、le, or rundown of corrosion products onto directly visible surfaces, at the specified test interval. Evaluation shall be done without magnification at a normal reading distance. 3.6.1.1 Potential Assembly Damage Assembly of components onto a vehicle can result in damage to the coating. Where possibl
28、e, assembly damage should be simulated prior to the start of corrosion testing. 3.6.1.2 Exceptions Depending upon vehicle location of the part, exceptions to this requirement may apply. Any exceptions are listed in Global Engineering Standard for Total Vehicle Corrosion Resistance, 18-0040 (RQT-0011
29、01-002492), and illustrated in the appended photo evaluation guide. 3.6.2 Water Resistance 240 hours (FLTM Bl 104-01) The finish shall not blister or show any signs of ferrous corrosion. Adhesion shall meet the requirements in section 3.5.2. 3.6.3 Fluid Resistance (FLTM BI 168-01, Method A, Gasoline
30、, Diesel, Coolant, Engine Oil, Transmission Fluid and Brake Fluid, other fluids as appropriate for application) The finish shall not blister or show any signs of softening or dulling. Adhesion shall meet the requirements in section 3.5.2. 3.7 THREAD ACCEPTANCE REQUIREMENTS (WA900, WE900, WX100) For
31、thread acceptance requirements see Ford Worldwide Fastener Standards WA900, WE900 and WX100. 3.8 FORMABILITY Standard Parts such as brackets, stampings, etc. that will be post formed following processing shall follow coating manufacturers approved procedures; such as, ISO 8401-1986 (E) cylindrical m
32、andrel bending ensuring bendability, must be used and results recorded. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2018, Ford Global Technologies, LLC Page 5 of 7 3.9 PROCESS CONTROL ITEMS Control items must be run as specified in Table 1 and control of these items must be represe
33、nted in the PFMEA and control plan. After review and sign-off of the control documents (PFMEA, CP and SPC data) for a significant number of lots, the frequency of the testing can be reduced as agreed upon by the Fastener Engineering representative. Other testing in this specification is for initial
34、approval or on an “as requested” basis and is not required for annual recertification. 3.9.1 Neutral Salt Spray Corrosion Test (SAE/USCAR-1, ASTM B 117) Non-Ferrous Corrosion Ferrous Corrosion As-Processed Baked As-Processed Baked WSS-M21P52-A1 72 h 48 h 240 h 240 h WSS-M21P52-A2 120 h 72 h 384 h 36
35、0 h WSS-M21P52-A3 96 h 72 h 240 h 196 h WSS-M21P52-A4 120 h 72 h 384 h 360 h Neutral salt spray (NSS) testing shall not be used in demonstrating initial conformance to this specification. Fasteners coated to these specifications shall be tested and evaluated in accordance with SAE/USCAR-1, both in t
36、he as-plated, trivalent chromium and sealed condition (as-processed) and after being held at 120 C for 4 hours (baked), and shall have the specified NSS performance. 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of these s
37、pecifications. Contact for questions concerning Engineering Material Specifications. 4.1 SIGNIFICANT SURFACES Significant surfaces should be noted on the Engineering Drawing. If not noted there, significant surfaces are generically defined as those surfaces on the finished part that: Are directly v
38、isible when the finished part is assembled in position. Can be a source of corrosion products directly visible, visible by reflection, or visible when they run down the part or onto other parts. Can affect fit or function of the part. Note: Small areas of ferrous corrosion may be allowed on sharp ed
39、ges, corners, and recesses due to reduced coverage of the electroplating. Recesses are generally defined as areas unreachable by a 13 mm (0.5 inch) diameter sphere. 4.2 WORLDWIDE FASTENER COATINGS When used for Worldwide Standard Parts, the Worldwide Fastener Finish Suffix as defined in Worldwide Fa
40、stener Standard WX100 shall be specified as shown below: Specification Finish WX100 Suffix WSS-M21P52-A1 ZinKlad 96 S437U WSS-M21P52-A2 ZinKlad 250 TNT15 S437 WSS-M21P52-A3 ZinKlad 250M TNT15 S437M WSS-M21P52-A4 ZinKlad 250 TNT08 S437L ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 20
41、18, Ford Global Technologies, LLC Page 6 of 7 4.3 RECOMMENDED TESTING REQUIREMENTS FOR DESIGN VALIDATION, PRODUCTION VALIDATION, AND SREA Coating performance is a function of material selection, surface preparation, and coating application. For established coatings and coating lines, this may permit
42、 a reduced test schedule to validate compliance to this specification. Use Table 1 below to determine the recommend test plan depending on the situation. This specification cannot prove out parts or coatings that involve changes in vehicle environment such as increased stone chipping or increased te
43、mperature. These changes may require vehicle testing, consult SDS/ARL requirements. 4.4 APPROVAL OF MATERIALS Suppliers desiring approval of their materials shall first obtain an expression of interest from Purchasing, Design or Product Development, and Materials Engineering. The supplier shall subm
44、it a completed copy of their laboratory test reports, signed by a qualified and authorized representative of the test facility, demonstrating full compliance with all the requirements of the Material Specification. Tested material samples must be available for review upon request and kept for a mini
45、mum of one year. Upon request, the supplier will review the associated quality control documents (Process Failure Mode and Effects Analysis, Control Plans, Certification testing) with Ford. 4.5 SUPPLIERS ONGOING RESPONSIBILITY All materials must be equivalent in all characteristics to the material u
46、pon which approval was originally granted. Prior to making any changes to the material originally approved, whether or not such changes affect the materials ability to meet the specification requirements, the supplier shall notify the affected Supplier Technical Assistance (STA), Purchasing, and Mat
47、erials Engineering activities of the proposed changes (with reasons) by submission of a completed Suppliers Request for Engineering Approval, SREA. For parts and components using Ford Engineering Material Specifications, all samples tested to the specifications for Design Verification (DV), Producti
48、on Verification (PV) and Production Part Approval Process (PPAP) sign off must be kept until Job 1. 4.6 RESTRICTED SUBSTANCE MANAGEMENT STANDARD Substance restrictions imposed by regulations or Company direction applies to the materials addressed by this document. The restrictions are identified in
49、the Restricted Substance Management Standard WSS-M99P9999-A1 which is updated yearly. It is the suppliers responsibility to comply with this standard on a continuing basis through IMDS and or GMAP reporting. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2018, Ford Global Technologies, LLC Page 7 of 7 New Coating Material Established Coating Material All Applicators New Applicator Existing Applicator Test
