1、 ENGINEERING MATERIAL SPECIFICATION Material Name Specification Number Date Action Revisions 2002 09 23 Revised Updated and renumbered 1988 12 21 B/O31519TC 3.2.1 Revised 1987 11 18 SM/ER 1265 TC Released. J P C Lines, K J Thurgood. EAO Printed copies are uncontrolled Page 1 of 4 Copyright 2002, For
2、d Global Technologies, Inc. BEARINGS - STEEL - ROLLER AND BALL WSD-M1A307-A THROUGH HARDENED OR CASE HARDENED 1. SCOPE The materials defined by this specification are used to manufacture general purpose, anti-friction, ball, tapered roller or cylindrical roller bearings. 2. APPLICATION This specific
3、ation was released originally for material used in automotive chassis components, such as rear wheel bearings, differential bearings and pinion bearings; also transmission bearings. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform
4、to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.2 MATERIALS 3.2.1 CUPS, CONES, BALLS AND ROLLERS Bearing quality, plain carbon or alloy steel, having a cleanliness rating to pass ASTM A534 (case hardened steels)-maximum rating as in table 2 or ASTM A295 (through ha
5、rdened steels)-maximum rating as in table 3. 3.2.2 CAGES Low carbon steel. Non metallic cages may be supplied in applications as specified on the Engineering Drawing. 3.3 THROUGH HARDENED BEARINGS 3.3.1 MICROSTRUCTURE The microstructure shall be maintained consistent with the initially approved samp
6、le. ENGINEERING MATERIAL SPECIFICATION WSD-M1A307-A Page 2 of 4 Copyright 2002, Ford Global Technologies, Inc. 3.3.1.1 QUENCHED AND TEMPERED Fine acicular martensite with a uniform distribution of fine globular carbides. Decarburisation or a cementite network is not permitted. 3.3.1.2 ISOTHERMAL TRA
7、NSFORMATION (Optional) Bainite (upper, lower or both) with a uniform distribution of fine globular carbides. Decarburisation or a cementite network is not permitted. 3.3.1.3 GRINDING BURNS Cups, cones, balls and rollers shall be free of grinding burns. 3.3.2 HARDNESS (CORE AND SURFACE) Cups and Cone
8、s : 59 - 65 HRC Rollers and Balls : 60 - 66 HRC 3.4 CASE HARDENED BEARINGS (NOTE: Not applicable to Balls) 3.4.1 MICROSTRUCTURE The microstructure shall be maintained consistent with that of the initially approved sample. 3.4.1.1 The case shall be tempered martensite without detrimental amounts of r
9、etained austenite or massive carbides and with no evidence of surface decarburisation. The core shall be free of any detrimental amount of ferrite. 3.4.1.2 GRINDING BURNS Cups, cones and rollers shall be free of grinding burns. 3.4.2 HARDNESS Case: (operating surfaces) 58 - 63 HRC Core: (measured ne
10、ar maximum cross section) 46 HRC max ENGINEERING MATERIAL SPECIFICATION WSD-M1A307-A Page 3 of 4 Copyright 2002, Ford Global Technologies, Inc. 3.4.3 HARDENING 3.4.3.1 TAPERED ROLLER BEARINGS Parts shall be case hardened to meet the case depth limits for the cup, cone, and tapered rollers. The Ford
11、Manufacturing Standard HT 4-1 designation for effective case depth equivalent to a hardness of 50 HRC shall be used. CASE DEPTH REQUIREMENTS Minimum Cross Section Minimum Case Maximum Case Dimension A Depth Depth * Thinnest Thickest Percent of Dimension B Cups 1.91 mm 2.67 mm 0.48 mm * 2.68 mm 4.52
12、mm 0.53 mm * 4.53 mm 8.94 mm 0.61 mm 30 8.95 mm 14.83 mm 0.79 mm 25 14.84 mm 17.75 mm 0.91 mm 20 Cones 1.91 mm 4.93 mm 0.48 mm * 4.94 mm 8.94 mm 0.53 mm * 8.94 mm 13.08 mm 0.61 mm 30 13.08 mm 14.83 mm 0.91 mm 30 14.84 mm 16.15 mm 0.97 mm 20 Rollers 4.09 mm 5.08 mm 0.53 mm 35 5.09 mm 6.60 mm 0.61 mm
13、30 6.61 mm 9.14 mm 0.79 mm 30 9.15 mm 13.99 mm 0.91 mm 25 14.00 mm 16.76 mm 0.97 mm 20 16.77 mm 20.32 mm 1.12 mm 15 * The core hardness limitation of 46 HRC maximum applies. * Certain bearings of unique design which require an additional 5% over the specified maximum limits shall be as specified on
14、the Engineering drawings. ENGINEERING MATERIAL SPECIFICATION WSD-M1A307-A Page 4 of 4 Copyright 2002, Ford Global Technologies, Inc. 3.4.3.2 CYLINDRICAL ROLLER BEARINGS Parts shall be case hardened to meet the case depth limits for the cups. cones and cylindrical rollers as specified on the Engineer
15、ing drawings. 3.5 RESIDUAL MAGNETISM Bearings shall be de-magnetised prior to shipment by the vendor. Any cone assembly or cup, when checked on a residumeter, shall indicate less than 0.001 T (tesla) residual magnetism. 3.6 COMBINATIONS The Engineering drawing may detail specific combinations of through hardened and case hardened components in the bearing.
