1、ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev 06 2014 09 10 N Status N status A4 replaced by WSS-M21P36-A7, A5 C. Mracna, NA replaced by WSS-M21P36-A8, A6 replaced by WSS-M21P36-A9 2013 08 13 Revised See summary of revisions C. Mracna, NA 2012 02 28 Revised/Activated Added suffixes A7
2、/A8/A9 C. Mracna, NA Controlled document at www.MATS Copyright 2014, Ford Global Technologies, LLC Page 1 of 4 BALL STUD CORROSION PROTECTIVE COATING, ZINC/ALUMINUM WSS-M21P36-A4 BASECOAT, SPRAY APPLIED, MODIFIED LUBRICATED SEALER, TEMPER EMBRITTLEMENT AVOIDANCE NOT TO BE USED FOR NEW DESIGN BALL ST
3、UD CORROSION PROTECTIVE COATING, ZINC/ALUMINUM WSS-M21P36-A5 BASECOAT, SPRAY APPLIED, SEALER, TEMPER EMBRITTLEMENT AVOIDANCE NOT TO BE USED FOR NEW DESIGN BALL STUD CORROSION PROTECTIVE COATING, ZINC/ALUMINUM WSS-M21P36-A6 BASECOAT, SPRAY APPLIED, LUBRICATED SEALER, TEMPER EMBRITTLEMENT AVOIDANCE NO
4、T TO BE USED FOR NEW DESIGN BALL STUD CORROSION PROTECTIVE COATING, ZINC/ALUMINUM WSS-M21P36-A7 BASECOAT, MODIFIED LUBRICATED SEALER BALL STUD CORROSION PROTECTIVE COATING, ZINC/ALUMINUM WSS-M21P36-A8 BASECOAT, SEALER BALL STUD CORROSION PROTECTIVE COATING, ZINC/ALUMINUM WSS-M21P36-A9 BASECOAT, LUBR
5、ICATED SEALER 1. SCOPE The materials defined by these specifications are corrosion protective coatings over steel that are heat converted from an aqueous dispersion of zinc and aluminum flakes, and oxides. These coatings are top-coated with sealers or topcoats to provide lubricity for consistent tor
6、que-tension control and to enhance corrosion protection. In both liquid and dry film, they are free of chromium, nickel, lead, and cadmium. 2. APPLICATION These specifications were released originally as a water based corrosion protection coating for suspension and steering heat treated/hardened bal
7、l joint studs where sacrificial corrosion protection, galvanic corrosion protection, controlled coating thickness (thread fill) and controlled coefficient of friction (rubber seal) are important considerations. The pretreatment and coating process shall not induce conditions resulting in hydrogen em
8、brittlement, temper embrittlement or loss of mechanical properties. These coatings will provide good bimetallic corrosion resistance when in contact with aluminum. They should not be applied to parts in contact with uncoated copper, magnesium or stainless steel. 2.1 LIMITATIONS A4/A5/A6 Cure tempera
9、ture must be in the range of 245-265C. A7/A8/A9 Coating parts with hardnesses higher than Property Class 10.9 is not allowed. Coating case hardened parts may temper the case hardness. The case hardness loss should be measured and reviewed by Ford Product Engineering prior to application. ENGINEERING
10、 MATERIAL SPECIFICATION WSS-M21P36-A4/A5/A6/A7/A8/A9 Copyright 2013, Ford Global Technologies, LLC Page 2 of 4 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99
11、P1111-A). 3.2 APPEARANCE The coating shall be uniform in color, roughness, and free from discontinuities. 3.3 CORROSION TESTING (ASTM B 117, CETP 00.00-L-467, ASTM D 610) 3.3.1 Parts shall pass the number of salt spray hours / cyclic corrosion weeks per Table 1. 3.3.2 Parts shall show no single ferr
12、ous corrosion spot larger than 1.5 mm in diameter or exceed ASTM D 610, grade 8. 3.4 COATING THICKNESS AND COATING WEIGHT (MASS) (ASTM B 568/ISO 3497, ASTM B 499/ISO 2178) The coating thickness and minimum coating weight are given in Table 1. The coating thickness can be measured on flat surfaces us
13、ing a magnetic induction thickness instrument (ASTM B 499/ISO 2178) or by calibrated X-ray florescence spectroscopy (ASTM B 568/ISO 3497), and should be based on an average of at least ten measurements. Alternatively, the thickness of the basecoat can be determined using a weight-strip-weigh method.
14、 Details of this method are available from the coating manufacturer. 3.5 THREAD ACCEPTANCE REQUIREMENTS (WA900, WE900, WX100) For thread acceptance requirements see Ford Worldwide Fastener Standards WA900, WE900 and WX100. 3.6 CLEANING (SAE J444)Prior to coating, the parts shall be free of oil, scal
15、e, oxides and foreign materials. The cleaning process shall have no detrimental effect on the substrate, including freedom from embrittlement. All heat treated or threaded parts must be alkaline degreased. Alternative cleaning techniques, such as alkaline cleaning followed by a phosphate may be used
16、. Dry honing (glass bead) may be required for some parts. Exception must be noted in the applicators control plans and approved by the coating manufacturer and end user. 3.7 ADHESION The coating shall withstand normal handling, storage, and installation without flaking or peeling or other loss of ad
17、hesion. ENGINEERING MATERIAL SPECIFICATION WSS-M21P36-A4/A5/A6/A7/A8/A9 Copyright 2013, Ford Global Technologies, LLC Page 3 of 4 3.8 TORQUE-TENSION (SAE/USCAR-11) The coating shall meet the required torque and friction coefficient specified in Table 1. 3.9 COATING SURFACE ROUGHNESS The coating surf
18、ace roughness (Rz) shall be specified on the engineering drawing. 3.10 MEK RUB CURE TEST The coating shall withstand ten double rubs with moderate pressure using cheesecloth saturated with methyl ethyl ketone. Slight dulling and/or color transfer of the coating is permitted. 4. GENERAL INFORMATION T
19、he information given below is provided for clarification and assistance in meeting the requirements of this specification. Contact for questions concerning Engineering Material Specifications. 5. SUMMARY OF REVISIONS 2013 08 13 Updated thickness ranges in Table 1. 2013 02 08 Updated spec titles for A7, A8, plain washer; zinc plated nut; 36.1 kN of tension * DIN 946 * Threaded surfaces 72 hours minimum
