1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev. 04 2014 05 14 Re-Activate Coating is still used for U bolt applications G. Weber, NA 2012 12 04 N Status Replaced by WSD-M21P11-B2 G. Weber, NA 1998 07 29 Activated D. Drobnich Controlled document at www.MATS Copyright 2014, Ford Global
2、Technologies, LLC Page 1 of 2 CORROSION PROTECTIVE COATING, ORGANIC POLYMER, WSS-M21P28-A2 FRICTION-MODIFIED 1. SCOPE This specification defines the material and performance criteria of a corrosion-protective and torque-tension enhancing coating consisting of an organic water-borne top coat applied
3、to zinc phosphated ferrous parts. 2. APPLICATION This specification was originally released as an economical corrosion-protective coating upgrade for fasteners and small parts in chassis exterior applications where a phosphate and oil finish was previously used. It is not intended for body interior
4、applications, high temperature applications, applications in direct contact with plastics, applications directly exposed to solvents, or areas of high visibility. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Sta
5、ndard Requirements For Production Materials (WSS-M99P1111-A). 3.2 ZINC PHOSPHATE SUBSTRATE (FLTM AQ 101-03) Metal surfaces to be phosphated must be free of soil, grease, rust, and scale. The zinc phosphate substrate shall have a smooth, compact, macrocrystalline structure which forms a dense, unifor
6、m coating, free from voids. A minimum phosphate coating weight of 32.3 g/m2, as deposited on a steel panel processed through the production line, is required to maintain good overall performance of the coating. 3.3 SEAL TREATMENT A chrome free final seal treatment may be applied to the phosphated su
7、rface prior to the topcoat. 3.4 TOP COAT THICKNESS A specific top coat thickness is not specified. The minimum thickness shall be sufficient to meet the corrosion resistance requirements. A typical film build which exhibits the appropriate corrosion resistance and torque-tension characteristics is a
8、pproximately 12.5 micrometers in thickness. Excessive coating thickness on threaded components may cause assembly concerns. The general requirements of the Ford Worldwide Fastener Standards, Finish Specification WX 100, Section 5 apply to this coating. ENGINEERING MATERIAL SPECIFICATION WSS-M21P28-A
9、2 Copyright 2014, Ford Global Technologies, LLC Page 2 of 2 3.5 APPEARANCE The coating shall be black in color and have a uniform semi-gloss appearance. The parts must be dry to the touch such that when held with a Watmans No. 41 filter paper, or equivalent, and applying hand pressure for 5 - 10 sec
10、onds, there shall be no visible staining of the filter paper when viewed without using supplementary magnification. For referee purpose, this test shall be carried out by using a force of 10 N. 3.6 CORROSION RESISTANCE 24 h min (SAE/USCAR-1) Parts tested for 120 hours shall exhibit less than 5% ferr
11、ous corrosion of the base metal on significant surfaces. To evaluate base metal corrosion, parts may be lightly brushed to remove any staining that may have occurred. At its option, Ford Engineering will periodically process parts finished to this specification at the Arizona Proving Ground or equiv
12、alent test facility to assess corrosion resistance. 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of this specification. Contact for questions concerning Engineering Material Specifications. 4.1 ADHESIVE OR SEALER COMPOUN
13、DS The application of adhesive or sealer compounds to threaded fasteners shall be done after the coating process. The applicator of the adhesive or sealer compound shall be responsible for assuring compliance to all performance requirements of the specified compound. 4.2 POLYAMIDE OR FLUOROCARBON CO
14、MPOUNDS The application of polyamide or fluorocarbon compounds to threaded fasteners shall be done after phosphating and prior to the topcoat. The applicator of the polyamide or fluorocarbon compound shall be responsible for assuring compliance to all performance requirements of the specified compound.
