1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions Ver 3 2008 05 28 N-STATUS N-Status due to lead content per WSS-M99P9999-A1(RSMS) L. Hess, FNA 2003 10 10 Revised Para 3.0 inserted; para 3.1, 3.9 and 4 deleted 1991 03 26 C10128522 Released N. Riley EAO, P. Lee NAAO Printed copies are uncontro
2、lled Copyright 2008, Ford Global Technologies, LLC Page 1 of 2 BEARINGS, IMPREGNATED BRONZE STEEL BACKED WSD-M8A22-A1 WSD-M8A22-A2 WSD-M8A22-A3 NOT TO BE USED FOR NEW DESIGN 1. SCOPE The materials defined by these specifications are a range of porous bronze alloys impregnated with a low friction, dr
3、y lubricant, and bonded to a low carbon steel backing. 2. APPLICATION These specifications were released originally for material used to reduce friction in bearing applications under a range of lubricating conditions. 3. REQUIREMENTS 3.0 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppli
4、ers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.2 CONSTRUCTION The bearing shall consist of a porous bronze matrix sintered onto a steel backing strip. A copper flash, to assist adhesion is optional. A dry lubricant mixture, cons
5、isting of polytetrafluorethylene (PTFE) with one or more of the fillers, shall be impregnated into the pores and also pressed onto the functional surface to form a continuous adherent overlay. 3.3 CHEMICAL COMPOSITION (weight, %) 3.3.1 Steel Backing Cold rolled low carbon steel 0.03 - 0.25% carbon.
6、3.3.2 Functional Layer (without overlay and after ashing off) A1 A2 A3 Tin 9.1 - 12.0 10.0 - 12.0 9.0 - 12.0 Copper Balance 83 - 87 Balance Lead 9.0 - 12.0 3.0 - 5.0 1.0 max Phosphorous 0.1 max 0.5 max 0.5 maxSilicon 0.2 max 0.2 max - Total Others 0.5 max 0.5 max 0.5 max Iron - - 0.2 maxZinc - - 2.0
7、 max ENGINEERING MATERIAL SPECIFICATIONWSD-M8A22-A1/A3 Printed copies are uncontrolled Copyright 2008, Ford Global Technologies, LLC Page 2 of 2 3.3.3 Impregnant/Overlay Lubricant Mixture (Volume % - Nominal) PTFE 75 80 65 80 80 11 Lead 25 - 35 20 - - Molybdenum Disulphide - 20 - - - 1 Nylon 66(PA66
8、) - - - - - 88 Fluorspar - - - - 20 - Total Others -2.0 maximum- The anticipated working compositions of the lining, interlayer and impregnant shall be restricted to a band within the above requirements as part of the control plan. 3.4 LAYER THICKNESSES The thicknesses of the layers and backing shal
9、l be specified on the Engineering Drawing. 3.5 INTERLAYER COLLAPSE TEST (in process) 3% max measured by conventional metrological technique The bronze interlayer shall not collapse more than 3.0% after applying a uniform compressive stress of 275 MPa by a hardened circular faced indentor of a diamet
10、er 40 to 60% of the test coupon width. 3.6 MECHANICAL PROPERTIES The mechanical properties of the steel backing shall be controlled directly or indirectly (e.g., hardness) as part of the control plan to ensure consistent installation and functional characteristics. 3.7 MICROSTRUCTURE Uniform distrib
11、ution of bronze particles and impregnant bonded to a steel backing, or copper bonding layer if used, with no bonding or interface defects when viewed at 100 times magnification. 3.8 HEALTH HAZARD WARNING Bearings to these specifications must not be machined or otherwise modified on Ford locations without adequate ventilation and hygiene controls (consult medical/industrial hygiene departments for details).
