1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions 2011 06 28 Activated D. Drobnich, FNA Controlled document at www.MATS Copyright 2011, Ford Global Technologies, LLC. Page 1 of 7 FASTENER FINISH, ELECTROPLATED ZINC-NICKEL, WSS-M21P51-A1 TRIVALENT CHROMIUM PASSIVATE, SILVER FASTENER FINISH, E
2、LECTROPLATED ZINC-NICKEL, WSS-M21P51-A2 TRIVALENT CHROMIUM PASSIVATE, LUBRICATED SEALER, SILVER FASTENER FINISH, ELECTROPLATED ZINC-NICKEL, WSS-M21P51-A3 TRIVALENT CHROMIUM PASSIVATE, LUBRICATED SEALER, ENHANCED LUBRICITY, SILVER FASTENER FINISH, ELECTROPLATED ZINC-NICKEL, WSS-M21P51-A4 TRIVALENT CH
3、ROMIUM PASSIVATE, LUBRICATED SEALER, DURABLE LUBRICITY, SILVER FASTENER FINISH, ELECTROPLATED ZINC-NICKEL, WSS-M21P51-A5 TRIVALENT CHROMIUM PASSIVATE, LUBRICATED SEALER, BLACK FASTENER FINISH, ELECTROPLATED ZINC-NICKEL, WSS-M21P51-A6 TRIVALENT CHROMIUM PASSIVATE, LUBRICATED SEALER, ENHANCED LUBRICIT
4、Y, BLACK 1. SCOPE The materials defined by these specifications are corrosion protective coatings over steel and iron substrates. All consist of an alkaline zinc nickel alloy and trivalent chromium passivate. A2, A3, A4, A5 and A6 are also coated with a clear sealer to increase corrosion resistance
5、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 used to produce these coatings may induce hydrogen embr
6、ittlement 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 standard parts A2 Corrosion resistance plus lubrication for threaded fasteners such as self tapping screws, thread
7、forming screws for plastic and those with ISO metric screw threads; can be used in grounding applications A3 Corrosion resistance plus enhanced lubrication for threaded fasteners such as thread forming screws for metal; can be used in grounding screw applications A4 Corrosion resistance plus a speci
8、al lubricant specifically designed for conical wheel nuts A5 Class A black appearance with corrosion resistance plus lubrication for threaded fasteners such as self tapping screws, thread forming screws for plastic and those with ISO metric screw threads A6 Class A black appearance with corrosion re
9、sistance plus enhanced lubrication for fasteners such as thread forming screws for metal ENGINEERING MATERIAL SPECIFICATION WSS-M21P51-A1/A2/A3/A4/A5/A6 Controlled document at www.MATS Copyright 2011, Ford Global Technologies, LLC. Page 2 of 7 2.1 SERVICE APPLICATION 2.1.1 The recommended maximum co
10、ntinuous service temperature is 310C. 2.1.2 A2 and A3 exhibit electrical continuity to the substrate and are suitable for most electrical grounding applications. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Qual
11、ity 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 effects of hydrogen embrittlement or other factors whi
12、ch 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. Applicators must have documentation to show that proce
13、dures and recommendations are being followed. 3.3.2 Prior to 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. See WSS-M99A3-A. 3.3.3 The se
14、alers 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 recommendations concerning the drying te
15、mperature and spin speeds suitable for the basket diameter being used. 3.4 COATING APPEARANCE 3.4.1 The base zinc-nickel plating will have a metallic silver appearance prior to passivate application. 3.4.2 The passivate layer for A1, A2, A3 and A4 will have an appearance of slight iridescence and co
16、lor variation consistent with interference films (e.g. yellow, orange, green, blue, purple variegation). 3.4.3 The passivate layer for A5 and A6 will be black. 3.4.4 The sealers used for A2, A3, A5 and A6 will be a translucent film free from discontinuities. ENGINEERING MATERIAL SPECIFICATION WSS-M2
17、1P51-A1/A2/A3/A4/A5/A6 Controlled document at www.MATS Copyright 2011, Ford Global Technologies, LLC. Page 3 of 7 3.4.5 The sealer used for A4 will be a translucent film but may contain some discontinuities in the form of touch marks or blemishes; however, they shall not adversely affect the mechani
18、cal performance or corrosion resistance of the part. 3.4.6 The sealers used for A2 and A3 may have additional color ID of green or blue. 3.5 COATING PROPERTIES 3.5.1 Composition The alkaline base zinc-nickel plating shall have a nickel content of 12 to 17% as measured by calibrated X-ray fluorescenc
19、e spectrometers in accordance with the suppliers requirements. The plating shall be a uniform, homogeneous alloy of zinc and nickel throughout the thickness of the deposit and across the high and low current densities of the part. Zinc-nickel alloy is the only deposit to be applied directly to the b
20、ase. The use of a zinc strike is not permitted. The composition of the zinc-nickel plating, passivate, and water soluble lubricated sealer shall all be in accordance with the chemical suppliers requirements. 3.5.2 Thickness (ASTM B659 / ASTM B487) 3.5.2.1 The electroplated zinc-nickel layer shall ha
21、ve 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. 3.5.2.2 The passivate layer thickness is not subject to measurement but will be less than 500 nanometers and greater than 50
22、nanometers. 3.5.2.3 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 sufficient to meet the corrosion requirements of the substrate material as well as the friction requirements. 3.5.2.4 The typical
23、overall thickness of these coatings is 10 to 12 micrometers. 3.5.3 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-embr
24、ittlement. Adhesion of the electroplate to the base metal must confirm to the requirements of the following test methods per ASTM B 571 unless otherwise indicated. ENGINEERING MATERIAL SPECIFICATION WSS-M21P51-A1/A2/A3/A4/A5/A6 Controlled document at www.MATS Copyright 2011, Ford Global Technologies
25、, LLC. Page 4 of 7 3.5.3.1 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 temperature. 3.5.3.2 Burnishing Test No blistering, lifting, or peeling of the electroplate from the substra
26、te is permitted following the burnishing test. 3.5.4 Torque Tension Performance (WZ101, Test Program B, M10x1.5 PC 8.8 surrogate bolt, 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 nom
27、inal value below: WSS-M21P51-A2 0.14 WSS-M21P51-A3 0.11 WSS-M21P51-A4 0.16 WSS-M21P51-A5 0.14 WSS-M21P51-A6 0.11 3.6 RESISTANCE PROPERTIES 3.6.1 Laboratory Accelerated Cyclic Corrosion Test (CETP 00.00-L-467) A1: Non-Ferrous Corrosion 6 weeks Ferrous Corrosion 9 weeks A2, A3, A4, A5, A6: Non-Ferrous
28、 Corrosion 9 weeks Ferrous Corrosion 12 weeks Evidence of corrosion products in excess of ASTM D 610, grade 6 (1%) on significant surfaces following at the specified test interval constitutes a failure. Evaluation shall be done without magnification at a normal reading distance. 3.6.2 Water Resistan
29、ce 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 3.5.3. 3.6.3 Fluid Resistance (FLTM BI 168-01, Method A, Gasoline, Diesel, Coolant, Engine Oil, Transmission Fluid and Brake Fluid, other fluids as appro
30、priate for application) The finish shall not blister or show any signs of softening or dulling. Adhesion shall meet the requirements in section 3.5.3. ENGINEERING MATERIAL SPECIFICATION WSS-M21P51-A1/A2/A3/A4/A5/A6 Controlled document at www.MATS Copyright 2011, Ford Global Technologies, LLC. Page 5
31、 of 7 3.6.4 Accelerated Weathering (A5 such as, ISO 8401-1986 (E) - cylindrical mandrel bending ensuring bendability, must be used and results recorded 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
32、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 approval or on an “as requeste
33、d” basis and is not required for annual recertification. 3.9.1 Neutral Salt Spray Corrosion Test (SAE/USCAR-1, ASTM B 117) A1: Non-Ferrous Corrosion 120 hours Ferrous Corrosion 600 hours A2, A3, A4, A5, and A6: Non-Ferrous Corrosion 240 hours Ferrous Corrosion 960 hours Neutral salt spray (NSS) test
34、ing 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 the as-plated, trivalent chromium and sealed condition (as-processed) and after being held at 120 C for 4 h
35、ours (baked), and shall have the specified NSS performance. ENGINEERING MATERIAL SPECIFICATION WSS-M21P51-A1/A2/A3/A4/A5/A6 Controlled document at www.MATS Copyright 2011, Ford Global Technologies, LLC. Page 6 of 7 4. GENERAL INFORMATION The information given below is provided for clarification and
36、assistance in meeting the requirements of these specifications. 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 s
37、urfaces of 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 visible when they run down the part or onto other parts. Can affect fit or function of the part. Note: Small area
38、s 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 (0.5 inch) diameter sphere. 4.2 WORLDWIDE FASTENER FINISHES When used for Worldwide Standard Parts, the Worldwide
39、Fastener Finish Suffix as defined in Worldwide Fastener Standard WX100 shall be specified as shown below: WSS-M21P51-A2 S450 WSS-M21P51-A3 S450L WSS-M21P51-A5 S450B WSS-M21P51-A6 S450BL 4.3 RECOMMENDED TESTING REQUIREMENTS FOR DESIGN VALIDATION, PRODUCTION VALIDATION, AND SREA. Coating performance i
40、s 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 the situation. This
41、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. ENGINEERING MATERIAL SPECIFICATION WSS-M21P51-A1/A2/A3/A4/A5/A6 Controlled
42、document at www.MATS Copyright 2011, Ford Global Technologies, LLC. Page 7 of 7 TABLE 1 New Coating Material Established Coating Material All Applicators New Applicator Existing Applicator Test Requirement All Parts Existing Part New Part Initial PPAP Production Control Process Change Example A Exam
43、ple B Example C Example D Example E 3.5.1 Composition X X X 1/lot 3.5.2 Thickness X X X 1/lot 3.5.3 Adhesion X X X 3.5.4 Torque Tension Performance X X X1 1/daily1 3.6.1 Laboratory Accelerated Cyclic Corrosion X X 3.6.2 Water Resistance X 3.6.3 Fluid Resistance X 3.6.4 Accelerated Weathering X Conta
44、ct Fastener or Materials Engineering 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. 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.
