1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions 2008 08 19 Activated D. Drobnich, FNA; D. Nymberg, FNA Printed copies are uncontrolled Copyright 2008, Ford Global Technologies, LLC Page 1 of 3 CORROSION PROTECTIVE COATING, LUBRICATED WSS-M21P43-A ACRYLIC TOPCOAT, CLEAR 1. SCOPE The materia
2、l defined by this specification is a protective, acrylic, cationic topcoat applied over various coatings over steel. It consists of a clear, waterborne, acrylic resin and associated make-up feed components, which are applied and cured in an oven. This cured coating provides a barrier layer for incre
3、ased protection from ultraviolet radiation, lubricity for consistent torque-tension control, and enhanced durability against part handling. In both bulk liquid and dry film, it is free of chromium, nickel, lead, and cadmium. 2. APPLICATION This specification was originally released as a secondary ba
4、rrier layer for corrosion protection coatings applied over steel fasteners exposed to direct sunlight. Per paragraph 3.4 of this specification, adhesion of this acrylic topcoat was tested over the fastener finish defined by specification WSS-M21P37-A1/A2. When applying this material over other coati
5、ngs, intercoat adhesion shall be tested. This topcoat is suitable for parts exposed to direct sunlight. Since hydrogen embrittlement is not induced by the process, this coating is suitable for high hardness parts. The cure temperature of the acrylic is 175 C to 190 C. This coating shall not be speci
6、fied if this temperature adversely affects the part being coated. 2.1 SERVICE TEMPERATURE The maximum continuous service temperature resistance of the material is 200 C. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Compa
7、nys Standard Requirements for Production Materials (WSS-M99P1111-A). 3.2 LICENSEE APPLICATOR QUALITY REQUIREMENTS Applicators must follow the coating manufacturers procedures and recommendations for chemical usage, equipment, and processing. 3.3 MATERIAL PERFORMANCE 3.3.1 Raw Material Storage Stabil
8、ity 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. ENGINEERING MATERIAL SPECIFICATION WSS-M21P43-A Printed copies are uncontrolled Copyright 2008, Ford Global Technologies, LLC Page 2 of 3 3.3.2 Cleaning Prior to
9、coating, the parts shall be free of oil, scale, and similar foreign materials. Any cleaning process shall have no detrimental effect on the basecoat or substrate, including freedom from embrittlement. 3.3.3 Curing The coating shall be cured 20 minutes at a metal temperature of 175 C to 190 C and sha
10、ll 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. ASTM D 5402-06 Method A may be used to test coating for cure; for fasteners, test the surface define
11、d in ISO 4042, paragraph 10.1, instead of the surface defined in paragraphs 6.2 and 6.3 of ASTM D 5402-06. 3.3.4 Finished Condition 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 to 10 seconds, there shall be no
12、visible staining of the filter paper when viewed without using supplementary magnification. For referee purposes, this test shall be carried out using a force of 10N. 3.3.5 Appearance The coating shall be transparent and may have a different gloss from the basecoat. 3.3.6 Storage Life Parts supplied
13、 shall still meet the requirements of this specification 6 months after receipt by Ford when stored at 5 C to 28 C with no direct heat or sunlight. 3.4 ADHESION The cured coating shall withstand normal handling, storage, and installation without flaking, peeling, or other loss of adhesion. Parts hea
14、ted to 120 C for 60 minutes 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 coating thickness will be done on parts passing the adhesion test. 3.5 RESIST
15、ANCE PROPERTIES 3.5.1 Corrosion Resistance This material shall be tested and evaluated in accordance with the corrosion requirements defined in the basecoat material specification. This material must not diminish the corrosion protection of the basecoat. In the event that the basecoat material speci
16、fication does not identify corrosion requirements, then, for fasteners, this material shall be tested according to the General Requirements of WX100. 3.5.2 Water Resistance (FLTM BI 104-01) Shall not blister or show any signs of red rust when subjected to immersion in water for 240 hours. ENGINEERIN
17、G MATERIAL SPECIFICATION WSS-M21P43-A Printed copies are uncontrolled Copyright 2008, Ford Global Technologies, LLC Page 3 of 3 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
18、.5.4 Hot Oil Resistance Shall not blister or show any signs of softening or dulling when subjected to immersion in engine oil (SAE 10W30 per WSE-M2C903-A2 or equivalent) for 24 hours at 66 3 C. 3.5.5 Ethylene Glycol Resistance Shall not blister or show any signs of softening or dulling when subjecte
19、d 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 approved brake fluid for 24 hours at 23 2
20、 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 WEIGHT (MASS) (ASTM B 568/ISO 3497, ASTM B 499/I
21、SO 2178) A specific topcoat thickness is not specified. The minimum thickness shall be sufficient to meet the ultraviolet exposure testing per paragraph 3.10. The maximum thickness must not impede part function, per paragraph 3.7 of this specification. A typical film build that exhibits the appropri
22、ate ultraviolet resistance is 10 - 15 micrometers in thickness. 3.7 THREAD ACCEPTANCE REQUIREMENTS (WA900, WE900, WX100) Excessive coating thickness on threaded components may cause assembly concerns. For thread acceptance requirements, see Ford Worldwide Fastener Standards WA900, WE900 and WX100. 3
23、.8 TORQUE-TENSION (WZ 101) Fasteners topcoated with this material shall meet the WZ101 required torque and friction coefficient when applied over basecoat materials. 3.9 ELECTRICAL CONDUCTIVITY This coating system is not recommended for electrical grounding applications. 3.10 ULTRAVIOLET EXPOSURE (ASTM D4587-01) Substrates topcoated with this material shall be tested and evaluated in accordance with ASTM D4587-01 for 1200 hours.
