1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2003 12 15 Activated R. Thomas/A. Lin Printed copies are uncontrolled Copyright 2003, Ford Global Technologies, Inc. Page 1 of 2 ANODIZED (ANODIC) COATING FOR CAST ALUMINUM, WSS-M4P12-A1 ELECTROLYTIC TYPE, HARD 1. SCOPE The material defined by
2、 this specification is a hard, uniform anodized (anodic) coating on cast aluminum alloy part surfaces. 2. APPLICATION This material specification was released originally for automotive pistons to improve top ring groove wear resistance at elevated temperatures, reduce micro welding of piston to ring
3、 and protect integrity of piston ring groove functional characteristics. 3. REQUIREMENTS Material specification requirements are to be used for initial qualification of materials. All requirements of this specification shall be met with data representing 3 sigma values. 3.1 STANDARD REQUIREMENTS FOR
4、 PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements for Production Materials (WSS-M99P1111-A). 3.2 BASE MATERIAL The requirements of the base material shall be as specified in the applicable Engineering Material Specification for the materia
5、l to be anodized. Microstructure shall consist of primary silicon crystallites in a matrix of unmodified aluminum silicon eutectic containing uniformly distributed intermetallic compounds. Grain size of primary aluminum, size and distribution of silicon, copper and intermetallic compounds shall be s
6、uitable to produce a consistent anodized surface. Base material shall be sufficiently free from surface defects, inclusions and excess copper-rich or silicon phases that are detrimental to functional use of the coating. 3.3 MICROSTRUCTURE OF ANODIZED SURFACE (ASTM E 3) The anodized surface layer sha
7、ll be uniform and continuous. Random microstructural discontinuities in anodized layer thickness in which silicon or copper-rich phases break the integrity of the anodized surface are permissible up to the following limits: ENGINEERING MATERIAL SPECIFICATIONWSS-M4P12-A1Printed copies are uncontrolle
8、d Copyright 2003, Ford Global Technologies, Inc. Page 2 of 2 Max. permissible discontinuity length: 0.07mm. Max. permissible discontinuity thickness: 0.02mm. Max. permissible number of discontinuities 0.01 mm in length: 10 (In a measurement length (L) of 0.45 mm 500X mag.) Micro-structural field sam
9、pling area and locations shall be as specified in suppliers Control Plan, Engineering Specification or Engineering Drawing. 3.4 THICKNESS OF ANODIZED LAYER (tn), MIN. 0.010 mm at top & bottom (ASTM B 244 or B 487) surface of top ring groove or as specified on Engineering Specification or Engineering
10、 Drawing 4. PROCESS Any process, including equipment, procedures, and operations may be used to produce a dense, high-quality anodized coating of the specified thickness on cast aluminum alloys which meets all requirements of this specification. 5. GENERAL INFORMATION The information given below is
11、provided for clarification and assistance in meeting the requirements of this specification. 5.1 REFERENCE DOCUMENTS The following documents are referenced in this specification: ASTM E 3 ASTM B 244 ASTM B 487 WSS-M99P1111-A 5.2 SUBJECT REFERENCES None 5.3 MICROWELDING START TEMPERATURE Micro-welding can start at a temperature as low as 150 C on an unanodized surface.
