1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2003 10 10 Revised Para 3.0 inserted; para 3.1, 3.2, 3.3, 3.9, 3.10 and 4 deleted 2000 05 26 Activated Replaces ESE-M8A7-A P. Lee Printed copies are uncontrolled Copyright 2003, Ford Global Technologies, Inc. Page 1 of 2 BEARING, STEEL BACKED,
2、 Cu-Pb, PLATED WSS-M8A7-C 1. SCOPE The material defined by this specification is a plated copper-lead alloy bearing metal on a steel backing. 2. APPLICATION This specification was released originally for material used as an insert type connecting rod or main bearing. 3. REQUIREMENTS 3.0 STANDARD REQ
3、UIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.4 COMPOSITION This material shall consist of a steel back bonded to a copper-lead alloy over which an electroplated barrier layer a
4、nd a lead base overlay are applied. The proportions of the copper-lead alloy and electroplated coatings to the steel back will be indicated on the part drawing, however, they will total approximately 15 - 20% of the overall thickness. The steel back shall be protected from corrosion by a flash elect
5、roplated coating or an oil-based preservative coating. 3.4.1 Backing SAE J403 1008 through SAE J403 1020 hot or cold rolled steel. Rockwell B hardness on finished part: Rod and Main Bearings, min 70 Flange Bearings, min 55 3.4.2 Lining Alloy Lead 21.0 - 27.0 Tin 0.15 - 1.50 Iron, max 0.35 Total Othe
6、r Elements, max 0.45 Copper Remainder 3.5 PLATED OVERLAY The finished copper-lead journal bearing surface shall be electroplated with a lead-tin alloy overlay to a thickness of 0.008 - 0.030 mm to obtain the final wall thickness. ENGINEERING MATERIAL SPECIFICATIONWSS-M8A7-CPrinted copies are uncontr
7、olled Copyright 2003, Ford Global Technologies, Inc. Page 2 of 2 3.5.1 Overlay Composition (SAE J460 192) Tin 8.0 - 12.0 Copper 1.0 - 4.0 Lead Balance 3.5.2 Plating Process It is not intended to limit in any way the procedure of plating. Any process resulting in a satisfactory adherent coating meeti
8、ng the requirement of this specification will be approved. 3.6 CORROSION PROTECTION The steel backing of the bearing shall be protected against corrosion by the application of a dry-to-touch Rust Preventative coating per a Ford approved specification, and by approval of Ford Materials Engineering. 3
9、7 LEAD-TIN MIGRATION PREVENTION A continuous electroplated flash nickel coating (0.00064 mm thick min) is required between the Cu-Pb alloy and the plated overlay. 3.8 QUALITY The quality of the bearing material and steel backing shall be uniform and free from surface or internal defects detrimental
10、 to the performance of the bearing. The bearing metal shall be firmly and continuously bonded to the steel back. The various electro-plated layers (the nickel barrier, the lead-tin overlay and the backing corrosion protection flash coating) must be firmly and continuously bonded to the previously applied layer.
