1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2007 05 08 Activated A. Cockman Printed copies are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 1 of 3 CORROSION PROTECTIVE COATING, ELECTROLYTIC ZINC PLATE, WSS-M21P50-A1 TRIVALENT CHROMIUM, TOPCOAT SEALER, INTEGRAL TORQUE
2、CONTROL LUBRICANT CORROSION PROTECTIVE COATING, MECHANICAL ZINC PLATE, WSS-M21P50-A2 TRIVALENT CHROMIUM, TOPCOAT SEALER, INTEGRAL TORQUE CONTROL LUBRICANT 1. SCOPE These specifications define the performance of an electrolytic and mechanical plating of zinc, followed by a trivalent chromium conversi
3、on, followed by the application of a topcoat sealer. 2. APPLICATION These specifications were originally released for coatings where resistance to corrosion is required for fasteners. These coatings are effective for preventing galvanic corrosion of steel fasteners that contact magnesium or aluminum
4、 components. Caution: These coatings are not recommended for severe abrasion conditions or where chip resistance is required. 2.1 SERVICE APPLICATION 2.1.1 The maximum service temperature resistance of these coatings is 120 C. 2.1.2 Electrical Conductivity 3. REQUIREMENTS Material specification requ
5、irements are to be used for initial qualification of materials. 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements for Production Materials (WSS-M99P1111-A). 3.2 APPEARANCE 3.2.1 The plating shall be smooth, fin
6、e grained, adherent, and free from blisters, pits, nodules, indications of burning, and other defects. All details of workmanship shall conform to the best practice for high quality plating. 3.2.2 Parts shall have a silver-white color. ENGINEERING MATERIAL SPECIFICATIONWSS-M21P50-A1/A2 Printed copie
7、s are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 2 of 3 3.3 PERFORMANCE CHARACTERISTICS Items to be tested for adhesion, plating thickness, or corrosion testing shall be air cured for 24 h prior to testing. 3.3.1 Adhesion Parts heated to 100 C for 30 minutes shall exhibit no bli
8、stering, peeling, or flaking of plating that can be removed by a filament type tape. The testing of plate quality by salt spray and/or determination of coating thickness shall be done on parts passing the adhesion test. 3.3.2 Plating Thickness, min 8 micrometers (ASTM B 659, ASTM B 487) The plating
9、thickness requirement identified above represents the minimum value and applies to all significant surfaces unless otherwise specified on the Engineering Drawing. In case of dispute, the thickness measurement umpire method shall be metallographic sectioning per ASTM B 487. 3.3.3 Corrosion Resistance
10、 (SAE/USCAR-1, ASTM B 117) 3.3.3.1 Fasteners 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 hours (baked), and shall pass the number of hours specified in the table below.
11、 See WX100 for additional information. 3.3.3.2 Parts other than fasteners shall be tested in accordance with ASTM B117, both in the as-plated, trivalent chromium and sealed condition (as processed) and after being held at 120 C for 4 hours (baked). Parts shall show no single ferrous corrosion spot l
12、arger than 1.5 mm in diameter, and shall not exhibit ferrous corrosion overall exceeding 0.1%, per ASTM D 610, grade 8, after the number of test hours specified in the table below. WHITE CORROSION RED CORROSION As-Processed Baked As-Processed Baked A1 96 72 384 360 A2 96 72 240 216 ENGINEERING MATER
13、IAL SPECIFICATIONWSS-M21P50-A1/A2 Printed copies are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 3 of 3 3.4 EMBRITTLEMENT (WSS-M99A3-A) Parts processed to this specification shall be free from the detrimental effects of hydrogen embrittlement or other factors which result in brit
14、tleness. All parts shall meet the requirements of WSS-M99A3-A. 3.4.1 When baking for hydrogen embrittlement relief is performed, post treatments will be performed after baking. 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements
15、 of these specifications. 4.1 REFERENCE DOCUMENTS The following documents are referenced in these specifications: ASTM B 117 ASTM D 610 WSS-M99A3-A ASTM B 487 QS-9000 WSS-M99P9999-A1 ASTM B 659 SAE/USCAR-1 WSS-M99P1111-A 4.2 WORLDWIDE FASTENER COATINGS When used for Worldwide Standard Parts, the Worldwide Fastener Coating suffix for WSSM21P50 - A1 is S449, and the suffix for WSS-M21P50-A2 is S449M.
