1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev 02 2012 12 06 N Status A1 replaced by WSS-M21P42-A3, G. Weber, NA 2006 01 20 Revised Added A4 version; Added para 3.5.1.1, 4, 4.1 Revised 2, 2.1, 3.4 & 3.5.1 L. Mastrofrancesco 2002 06 11 Activated D. Drobnich Controlled document at www.M
2、ATS Copyright 2012, Ford Global Technologies, LLC Page 1 of 5 CORROSION PROTECTIVE COATING, ZINC/ALUMINIUM WSS-M21P39-A1 BASECOAT, LUBRICATED SEALER, SILVER NOT TO BE USED FOR NEW DESIGN 1. SCOPE The materials defined by these specifications are corrosion protective coatings over steel that are heat
3、 converted from an aqueous dispersion of zinc and aluminum flakes, and oxides. These coatings include a sealer or topcoat to provide enhanced corrosion protection, color and/or consistent torque-tension control. They are free of chromium, nickel, lead and cadmium. 2. APPLICATION These specifications
4、 were released originally for materials used as water-based corrosion protective coatings over steel. Since hydrogen embrittlement is not induced by the process, these coatings are suitable for high hardness parts. The cure temperature of the zinc/aluminum coating is 270 to 330 C. These coatings sha
5、ll not be specified over case hardened parts (other than sheet metal screws) or parts where the curing temperature adversely affects the component being coated. These coatings provide good bi-metallic corrosion resistance when in contact with aluminum. They should not be applied to parts in contact
6、with uncoated copper, magnesium or stainless steel surfaces. The Worldwide Fastener Standard - WX100 Finish Specification - identifies recommended usages and special requirements for this material. Usages other than those identified in the WX100 specification have not been tested. 2.1 SERVICE TEMPER
7、ATURE The maximum continuous service temperature resistance of A1, A2 and A4 is 315 C. The maximum continuous service temperature of A3 is 182 C. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirement
8、s For Production Materials (WSS-M99P1111-A). ENGINEERING MATERIAL SPECIFICATION WSS-M21P39-A1 Copyright 2012, Ford Global Technologies, LLC Page 2 of 5 3.2 LICENSEE APPLICATOR QUALITY REQUIREMENTS Applicators must follow coating manufacturer procedures and recommendations for chemical usage, equipme
9、nt and processing. 3.3 MATERIAL PERFORMANCE 3.3.1 Raw Material Storage Stability The material must be capable of being stored at 23 +/- 2 C for 60 days without detrimental effect to the performance of the coated parts. 3.3.2 Cleaning Prior to coating, the parts shall be free of oil, scale, and simil
10、ar foreign materials. The cleaning process shall have no detrimental effect on the substrate, including freedom from embrittlement. All parts must be degreased (alkaline or vapor) and mechanically cleaned (shot blast). When shot blasting, S-70 (SAE J 444) type steel shot is recommended. Alternative
11、cleaning techniques may be required for some materials/parts such as parts made of powdered metal, screw/nut and washer assemblies, austempered spring clips, and some internally threaded fasteners. Each exception must be noted in the applicators control plan and approved by the coating manufacturer.
12、 3.3.3 Curing The coating is typically cured at a metal temperature of 270 to 330 C and shall not be used on materials that are adversely affected by these metal temperatures. Parts must be sufficiently cured at the time of packing to withstand normal handling and shipping without marring. 3.3.4 Fin
13、ished Condition Parts must be dry to touch such that, when held with a Watmans No.41 filter paper, or equivalent, and applying hand pressure for 5 to 10 seconds, there shall be no visible staining of the filter paper when viewed without using supplementary magnification. For referee purposes this te
14、st shall be carried out using a force of 10N. 3.3.5 Appearance The coating shall be uniform in color and free from discontinuities when viewed without magnification. 3.3.6 Storage Life Parts supplied shall still meet the specific requirements of this specification 6 months after receipt by Ford when
15、 stored at 5 to 28 C with no direct heat or sunlight. ENGINEERING MATERIAL SPECIFICATION WSS-M21P39-A1 Copyright 2012, Ford Global Technologies, LLC Page 3 of 5 3.4 ADHESION The cured coating shall withstand normal handling, storage and installation without flaking or peeling or other loss of adhesi
16、on. Parts heated to 120 C for 60 minutes, then cooled to 23 +/- 2 C at 50 +/- 5% relative humidity, shall not exhibit blistering, peeling, flaking or coating which can be removed by a filament type tape, such as 3M No. 898-2. The testing of coating quality by salt spray and/or determination of coati
17、ng thickness will be done on parts passing the adhesion test. 3.5 RESISTANCE PROPERTIES 3.5.1 Corrosion Resistance, WSS-M21P39-A1/A2/A3 (SAE/USCAR-1, ASTM B 117, ASTM D 610, WX100) Fasteners shall be tested and evaluated in accordance with SAE/USCAR-1, and shall pass the number of hours specified in
18、 Table 1 and the General Requirements of WX100. Parts other than fasteners shall be tested in accordance with ASTM B 117. Parts shall show no single ferrous corrosion spot larger than 1.5 mm in diameter, and shall not exhibit ferrous corrosion overall exceeding 0.1%, per ASTM D 610, grade 8, after t
19、he number of test hours specified in Table 1. 3.5.1.1 Cyclic Corrosion Resistance, WSS-M21P39-A4 (FLTM BI 123-02) Components shall be free of non-ferrous white corrosion (equivalent to ASTM D 610 rating 6 or better) after 10 cycles. A thin, uniform, whitish blush on the surface of the coating is nor
20、mal in cyclic testing or salt spray testing for A4 and is not cause for rejection unless voluminous. Components shall be free of ferrous corrosion (equivalent to ASTM D 610 rating 6 or better) after 50 cycles. 3.5.2 Water Resistance (FLTM BI 104-01) Shall not blister or show any signs of red rust wh
21、en subjected to immersion in water for 240 hours. 3.5.3 Gasoline Resistance Shall not blister or show any signs of softening or dulling when subjected to immersion in current factory fill gasoline for 24 hours at 23 +/- 2 C. 3.5.4 Hot Oil Resistance Shall not blister or show any signs of softening o
22、r dulling when subjected to immersion in engine oil (SAE 10W30 per WSE-M2C903-A2 or equivalent) for 24 hours at 66 +/- 3 C. ENGINEERING MATERIAL SPECIFICATION WSS-M21P39-A1 Copyright 2012, Ford Global Technologies, LLC Page 4 of 5 3.5.5 Ethylene Glycol Resistance Shall not blister or show any signs
23、of softening or dulling when subjected to immersion in a 50% solution of water and long life coolant concentrate (WSE-M97B44-B or equivalent) for 24 hours at 23 +/- 2 C. 3.5.6 Brake Fluid Resistance Shall not blister or show any signs of softening or dulling when subjected to immersion in currently
24、approved brake fluid for 24 hours at 23 +/- 2 C. 3.5.7 Power Steering/Transmission Fluid Shall not blister or show any signs of softening or dulling when subjected to immersion in current factory fill power steering and transmission fluid for 24 hours at 66 +/- 3 C. 3.6 COATING THICKNESS AND COATING
25、 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 should be measured on flat surfaces using a magnetic induction thickness instrument (ASTM B 499/ISO 2178) or by calibrated X-ray fluorescence spectro
26、scopy (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 weigh-strip-weigh method. Details of this method are available from the coating manufacturer. 3.7 THREAD ACCEPTANCE REQUIREMENTS (WA900,
27、 WE900, WX100) For thread acceptance requirements see Ford Worldwide Fastener Standards WA900, WE900 and WX100. 3.8 TORQUE-TENSION (WZ 101) The coating shall meet the required torque and friction coefficient specified in Table 1. ENGINEERING MATERIAL SPECIFICATION WSS-M21P39-A1 Copyright 2012, Ford
28、Global Technologies, LLC Page 5 of 5 TABLE 1 GUIDANCE TO PROPERTIES OF WSS-M21P39-A1 COATING SYSTEMS Specification Color # Coats (a) Min. Thickness m Min. Ct. Wt. g/m2 WZ 101 Torque Nm (b) WZ 101 Friction Coefficient N.S.S. Hrs. Ferrous Corrosion N.S.S. Hrs. Zinc Oxidation Examples of Part Applicati
29、ons WSS-M21P39-A1 Silver 2 + 1 5 min, basecoat 6-8 typical 6 min, total 7-10 typical 20 min, basecoat 24 min, total Mean: 41-46 3 Sigma: 35-52 Mean: 0.13 0.01 3 Sigma: 0.13 0.03 720 240 Parts for exterior use requiring lubrication, threaded fasteners M6 and larger. NOTE: (a) NUMBER OF COATS ARE FOR
30、DIP-SPIN APPLIED COATINGS AND MAY BE LESS DUE TO PROCESS. (b) BASED ON WZ101 TEST PROGRAM B. 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of these specifications. 4.1 CORROSION RESISTANCE (SAE/USCAR-1) Coated components tested in accordance with SAE/USCAR-1 and evaluated in accordance with ASTM D610, Grade 6, typically pass the following salt spray corrosion test hours. A4 240 hours to white corrosion and 840 hours to ferrous corrosion.
