1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2003 10 09 Revised Para 3.0 inserted; para 3.7 and 4 deleted 1984 10 08 Released H8Q-51 C. F. Carter Printed copies are uncontrolled Copyright 2003, Ford Global Technologies, Inc. Page 1 of 2 BEARING, STEEL BACKED, TFE-PB IMPREGNATED BRONZE ES
2、H-M8A6-A2 1. SCOPE The material defined by this specification is a steel backed, tetrafluoroethylene and lead impregnated porous bronze bushing. 2. APPLICATION This specification was released originally for material used for an A/C compressor shaft bearing. 3. REQUIREMENTS 3.1 STEEL BACKING Cold rol
3、led low carbon steel 0.04 - 0.15% carbon. 3.2 LINING INTERLAYER MATERIAL AND THICKNESS 3.2.1 Composition, % Tin 10.0 - 12.0 Copper 88.0 - 90.0 Total Others 0.25 max 3.2.2 Average Thickness 0.20 mm - 0.40 mm For initial approval section 30 bearings, mount and at 100 magnifications measure the thickne
4、ss from the steel backing to highest bronze particle in four areas. Thickness will be the average of 120 readings. 3.3 OVERLAY COMPOSITION AND THICKNESS 3.3.1 Composition (% by volume) Polytetrafluoroethylene 65 min Lead Powder 35 max 3.3.2 Average Film Thickness 0.020 +/- 0.010 mm For initial appro
5、val use the 30 mounted sections from 3.2.2. At 100 magnifications measure the thickness of PTFE in the four thinnest areas from the bronze particles to outer edge. Thickness will be the average of 120 readings. ENGINEERING MATERIAL SPECIFICATIONESH-M8A6-A2Printed copies are uncontrolled Copyright 20
6、03, Ford Global Technologies, Inc. Page 2 of 2 3.3.3 Penetration Lubricant shall penetrate the lining material to a minimum depth of 0.08 mm. 3.4 CRUSHING STRENGTH, min 276 MPa Apply load to PTFE - bronze lining. Bronze interlayer must not be collapsed as determined by sectioning or by a 3% maximum
7、change in section thickness as measured before and after loading. 3.5 BOND QUALITY (Steel Backing and Bronze) No flaking Test Method: Bend material through 90 around a radius not greater than 9-10 times the nominal steel thickness, with the lining material on the outside of the bend. 3.6 PLATING When required, the exposed steel backing and end faces will be protected by a tin flash to a maximum thickness of 0.002 mm.
