1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev 00 2013 03 22 Released G. Weber, NA Controlled document at www.MATS Copyright 2013, Ford Global Technologies, LLC Page 1 of 6 FASTENER FINISH, ELECTROPLATED ZINC, TRIVALENT WSS-M21P52-A1 CHROMIUM PASSIVATE, SILVER IRIDESCENT FASTENER FINI
2、SH, 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, ELECTROPLATED ZINC, TRIVALENT WSS-M21P52-A4 CHROMIUM PASSIVATE,
3、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 trivalent chromium passivate. A2, A3 and A4 are also coated
4、 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 parts used throughout the vehicle. Some of the processes u
5、sed 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 fasteners which subsequently receive an adhesive coating, an
6、d 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 embrittlement A4: Corrosion resistance plus enhanced lubri
7、cation 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 continuity to the substrate and may be used for electrical gro
8、unding 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 magnesium components. 2.1.4 These coatings are not recommen
9、ded for high visibility applications, severe abrasion conditions or where chip resistance is required. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2013, Ford Global Technologies, LLC Page 2 of 6 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers a
10、nd part producers must conform to the Companys Quality System Requirements for Production Materials (WSS-M99P1111-A). Part producers must use approved materials specified on the Companys Approved Source List. 3.2 EMBRITTLEMENT Parts coated to this specification shall be free from the detrimental eff
11、ects 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 Applicators shall follow material supplier procedures and recommendations for chemical usage, equipment, analysis, and processing. App
12、licators 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 adhesion of the coating. The substrate shall be free of oil, dirt, and similar foreign materials. If a cleaning process is necessa
13、ry, 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. 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
14、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 recommendations concerning the drying temperature and spin speeds suitable for the basket diameter being used. 3.3.5 The temperatures associa
15、ted 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 electroplated finish should be passivated and sealed after de-embrittlement heat treatment. 3.4 COATING APPEARANCE 3.4.1 The finis
16、hes 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 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 si
17、lver 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 for A2, A3 and A4 have a UV light visible tracer. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2013, Ford Global Te
18、chnologies, LLC Page 3 of 6 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 on flat surfaces. In case of dispute, the thickness measurement umpire method shall be metallographic sectioning per ASTM B487. 3.5
19、.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 is not subject to measurement but will be less than 2 micrometers and greater than 0.5 micrometers. The thickness shall be suffici
20、ent 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 12 micrometers. 3.5.2 Adhesion (ASTM B 571) The coating shall withstand normal handling, storage, and installation without flaking o
21、r 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 metal must conform to the requirements of the following test methods per ASTM B 571 unless otherwise indicated. 3.5.2.1 Heat Quenc
22、h 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 temperature. 3.5.2.2 Burnishing Test No blistering, lifting, or peeling of the finish from the substrate is permitted following the burnishing te
23、st. 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 accordance with Ford Worldwide Fastener Standard WZ101, coated fasteners shall have a friction coefficient within +/- 0.03 of the nominal value b
24、elow: WSS-M21P52-A2 0.15 WSS-M21P52-A3 0.15 WSS-M21P52-A4 0.08 ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2013, Ford Global Technologies, LLC Page 4 of 6 3.6 RESISTANCE PROPERTIES 3.6.1 Laboratory Accelerated Cyclic Corrosion Test (CETP 00.00-L-467) Non-Ferrous Corrosion Ferrous C
25、orrosion 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 parts whenever possible (not panels). Parts for testing shall have no visible non-ferrous corrosion products at the beginning of testing. P
26、arts shall be tested in vehicle orientation. Failure is constituted by evidence of corrosion products on surfaces directly visible in the application on the vehicle, or rundown of corrosion products onto directly visible surfaces, at the specified test interval. Evaluation shall be done without magn
27、ification 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 possible, assembly damage should be simulated prior to the start of corrosion testing. 3.6.1.2 Exceptions Depending upon vehicle location of the
28、part, exceptions to this requirement may apply. Any exceptions are listed in Global Engineering Standard for Total Vehicle Corrosion Resistance, 18-0040 (RQT-001101-002492), and illustrated in the appended photo evaluation guide. 3.6.2 Water Resistance 240 hours (FLTM Bl 104-01) The finish shall not
29、 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, Diesel, Coolant, Engine Oil, Transmission Fluid and Brake Fluid, other fluids as appropriate for application) The finish shall not blist
30、er 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 thread acceptance requirements see Ford Worldwide Fastener Standards WA900, WE900 and WX100. 3.8 FORMABILITY Standard Parts such as bracke
31、ts, stampings, etc. that will be post formed following processing shall follow coating manufacturers approved procedures; such as, ISO 8401-1986 (E) cylindrical mandrel bending ensuring bendability, must be used and results recorded. ENGINEERING MATERIAL SPECIFICATION WSS-M21P52-A1/A4 Copyright 2013
32、, Ford Global Technologies, LLC Page 5 of 6 3.9 PROCESS CONTROL ITEMS Control items must be run as specified in Table 1 and control of these items must be represented in the PFMEA and control plan. After review and sign-off of the control documents (PFMEA, CP and SPC data) for a significant number o
33、f 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 approval or on an “as requested” basis and is not required for annual recertification. 3.9.1 Neutral Salt Spray Corrosion Test (SAE/USCAR-
34、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 360 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 demonst
35、rating initial conformance to this specification. Fasteners coated to these specifications shall be tested and evaluated in accordance with SAE/USCAR-1, both in the as-plated, trivalent chromium and sealed condition (as-processed) and after being held at 120 C for 4 hours (baked), and shall have the
36、 specified NSS performance. 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of these specifications. Contact for questions concerning Engineering Material Specifications. 4.1 SIGNIFICANT SURFACES Significant surfaces should
37、 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 visible when the finished part is assembled in position. Can be a source of corrosion products directly visible, visible by reflection, or
38、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 edges, corners, and recesses due to reduced coverage of the electroplating. Recesses are generally defined as areas unreachable by a 13 mm (
39、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 Fastener Standard WX100 shall be specified as shown below: Specification Finish WX100 Suffix WSS-M21P52-A1 ZinKlad 96 S437U WSS-M21P52-A2 Zi
40、nKlad 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 2013, Ford Global Technologies, LLC Page 6 of 6 4.3 RECOMMENDED TESTING REQUIREMENTS FOR DESIGN VALIDATION, PRODUCTION VALIDATION, AND SREA
41、Coating performance is a function of material selection, surface preparation, and coating application. For established coatings and coating lines, this may permit a reduced test schedule to validate compliance to this specification. Use Table 1 below to determine the recommend test plan depending on
42、 the situation. This specification cannot prove out parts or coatings that involve changes in vehicle environment such as increased stone chipping or increased temperature. These changes may require vehicle testing, consult SDS/ARL requirements. New Coating Material Established Coating Material All
43、Applicators New Applicator Existing Applicator Test Requirement All Parts Existing Part New Part Initial PPAP Production Control Process Change Example A Example B Example C Example D Example E 3.5.1 Thickness X X X 1/lot 3.5.2 Adhesion X X X 3.5.3 Torque Tension Performance X X X1 1/daily1 3.6.1 La
44、boratory Accelerated Cyclic Corrosion X X Contact Fastener or Materials Engineering 3.6.2 Water Resistance X 3.6.3 Fluid Resistance X 3.7 Thread Acceptance X X X 1/lot 3.9.1 Neutral Salt Spray Corrosion X X X1/daily1 1 Potential use of surrogate data Example A: Approval of a new or alternate coating
45、. Example B: Verification of a new applicator to an established coating. Example C: Required validation for initial PPAP submission. Example D: Required testing to demonstrate ongoing production control. Example E: Level of testing is dependent on degree of change. Contact Fastener and/or Materials Engineering.
