1、 ENGINEERING MATERIAL SPECIFICATION Material Name Specification Number Date Action Revisions 2002 09 24 Revised Updated and renumbered 1991 07 16 C10124239 A2 Added; Rev.& Updated N. Riley, EAO P. Lee, NAAO 1984 08 29 SM/ER1482TC Released Printed copies are uncontrolled Page 1 of 3 Copyright 2002, F
2、ord Global Technologies, Inc. GREY IRON, CHILLED FACE TAPPET, HARDENED AND TEMPERED WSD-M1A276-A GREY IRON, CHILLED FACE TAPPET, AS CAST WSD-M1A276-A2 1. SCOPE The material defined by these specifications is a controlled low alloy cast iron capable of component surface mechanical chilling and respon
3、ding to subsequent heat treatment. 2. APPLICATION This material is primarily proposed for tappets, e.g. mushroom type, running against mechanically chilled camshafts. WSD-M1A276-A is applicable to the higher stressed applications. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Ma
4、terial suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.2 CHEMICAL COMPOSITION (Ladle Analysis, wt %) Total Carbon 3.25 - 3.55* Silicon 2.00 - 2.50 Sulphur 0.12 max Phosphorus 0.3 max Manganese 0.50 - 1.10 Chromium 0.20 - 0.
5、90 Molybdenum 0.75 max* Nickel 1.10 max Specific composition limits and foundry practice to meet performance and manufacturing requirements will form part of an agreed Control Plan for individual component geometries and process routes. 3.3 AS CAST PROPERTIES 3.3.1 Hardness A A2 Mechanical chilled f
6、ace + 48 HRC, min 50 HRC, min Body 285 HB, max 250 HB, min + Test at area equivalent to finished tappet face. ENGINEERING MATERIAL SPECIFICATION WSD-M1A276-A WSD-M1A276-A2 Page 2 of 3 Copyright 2002, Ford Global Technologies, Inc. 3.4 AS CAST PROPERTIES 3.4.1 Microstructure Chill surface +. Predomin
7、antly interdendritic and acicular carbide with dendritic pearlite. Due to rapid cooling rates, martenistic transformation products can also be present. Carbide orientation to be generally normal to cam face surface. Graphite, where present, shall be restricted to fine isolated interdendritic network
8、s. + Examine at area equivalent to finished tappet face. Body. Flake graphite type VII, with distribution and size predominantly A and 4 respectively (ASTM A 247), in a pearlitic matrix, some discontinuous carbide networks are permitted. 3.4.2 Chill Depth* Full Chill Depth +, min 1 mm Effective Chil
9、l Depth, min 2 mm + measure from area equivalent to finished tappet face. * See General Information for chill definitions. 3.5 HEAT TREATED REQUIREMENTS 3.5.1 Hardness A A2* local hardening Finished Machined Tappet, Chill face, min 60 HRC - Body, min 45 HRC 45 HRC * Location as directed on Engineeri
10、ng drawing. 3.5.2 Microstructure Finished machined tappet, chill surface (A Only). Interdendritic and acicular carbide and tempered martensite. Any temper graphite shall be well distributed in a fine aggregate form. Minimum primary carbide target levels to be 30 % with a 4 sigma allowance down to 20
11、 %. Maximum temper graphite target levels to be 5% with a 4 sigma allowance up to 6 %. Carbide and graphite levels to be part of the Control Plan. ENGINEERING MATERIAL SPECIFICATION WSD-M1A276-A WSD-M1A276-A2 Page 3 of 3 Copyright 2002, Ford Global Technologies, Inc. Body. Flake graphite and tempere
12、d martensite. N.B. See General Information for heat treatment information. 3.6 FREEDOM FROM DEFECTS As supplied, the casting shall be sound, clean, free from sand, cracks and porosity on machined or stress surfaces. 4. GENERAL INFORMATION The information given below is provided for clarification and
13、 assistance in meeting the requirements of this specification. 4.1 CHILL DEPTH DETERMINATION Based on macro examination viewed at a magnification 5 - 10 times surface prepared to 600 grit grinding paper, nital etch. Mechanically chilled surface measurements to be equivalent to finished machined tapp
14、et face. Full Chill Depth - Perpendicular depth from area equivalent to finished tappet face to onset of graphite or pearlite pools. Mottled Zone - Perpendicular from boundary of full chill zone to end of mechanical chill effect (i.e. limit of carbide networks). Effective Chill Depth - Full chill de
15、pth plus 50% mottle zone depth. 4.2 HEAT TREATMENT (A Only) Hardening shall be undertaken in such a manner as to minimize the solution of primary carbide and the precipitation of temper graphite. Process details will be dependent on equipment details, but large charge sealed quench or batch type fur
16、naces are not normally suitable. The following heat treatment has been found to give acceptable tappet performance: Low temperature soak e.g. 700 C for 1 h max. Hardening temperature 850 - 880 C. Holding time above 820 C 10 minutes (approx) maximum. Agitated oil quench. Tempering temperature 180 - 280 C (1 - 2 h at temperature).
