1、 ENGINEERING MATERIAL SPECIFICATION Material Name Specification Number Date Action Revisions 2002 09 23 Revised Updated and renumbered 1988 01 14 SM/ER 1620 TC Released. K J Thurgood. EAO. Printed copies are uncontrolled Page 1 of 4 Copyright 2002, Ford Global Technologies, Inc. STEEL FOR COLD FORME
2、D COIL SPRINGS WSD-M1A310-A1/A4 1. SCOPE The materials described in these specifications are plain carbon and alloy spring steels which have been hardened and tempered prior to coiling. 2. APPLICATION These materials were released originally for use in the manufacture of springs with wire diameters
3、between 8 and 16 mm. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements For Production Materials (WSS-M99P1111-A). 3.2 GENERAL REQUIREMENTS Prior to hardening and tempering, the bar stock shall e
4、ither be in the ground condition or have the decarburised layer removed. 3.3 REQUIREMENTS FOR FINISHED SPRINGS 3.3.1 GENERAL RESTRICTIONS 3.3.1.1 The component drawing may specify a restricted list of steel types together with other requirements such as hardness, surface condition, peening control,
5、etc., which have been applied to springs that have successfully met the rig and durability requirements. 3.3.1.2 No steels other than those proved to be acceptable by prototype testing may be used in production unless prior approval from Ford Product Development is obtained. 3.3.1.3 The component en
6、gineer must be supplied with the composition and properties of each batch of prototype springs. ENGINEERING MATERIAL SPECIFICATION WSD-M1A310-A1/A4 Page 2 of 4 Copyright 2002, Ford Global Technologies, Inc. 3.3.2 CHEMICAL COMPOSITION The spring manufacturer shall use steel that complies with one of
7、the following compositions: A1 A2 A3 A4 % % % % Carbon 0.55-0.75 0.45-0.55 0.58-0.75 0.50-0.60 Silicon 0.10-0.35 0.10-0.35 0.10-0.35 1.20-1.60 Manganese 0.60-1.20 0.60-0.90 0.50-0.90 0.50-0.80 Phosphorus 0.030 max 0.030 max 0.030 max 0.030 max Sulphur 0.030 max 0.030 max 0.030 max 0.030 max Chromium
8、 - 0.080-1.10 0.35-0.60 0.50-0.80 Vanadium - 0.15 min 0.10-0.30 - Type A4 is classified as a silicon steel 3.3.3 NON-METALLIC IMPURITIES INCLUSION TYPE A B T H T H Silicon Steel * * 2.5 1.5 Non-Silicon Steel * * 2.5 1.5 C D T H T H Silicon Steel 2.5 1.5 2 1.5 Non-Silicon Steel 1.5 1 2 1.5 *No requir
9、ement since % Sulphur is less than 0.035 The above requirement is either on billets to ASTM E45 Method A or on finished springs to FLTM EU-BA 51-2. 3.3.4 GRAIN SIZE The steel shall have an austenitic grain size of 5 or finer. ENGINEERING MATERIAL SPECIFICATION WSD-M1A310-A1/A4 Page 3 of 4 Copyright
10、2002, Ford Global Technologies, Inc. 3.3.5 DECARBURISATION (FLTM EU-BA 53-1) The following maximum limits of decarburisation shall apply to the finished spring. Complete decarburisation - Nil Partial decarburisation - 0.8% of the wire dia. 3.3.6 MICROSTRUCTURE The microstructure shall consist of tem
11、pered martensite and similar transformation products. Pearlite is not allowed. Free ferrite may only be present in the decarburised zone (see 3.2.5). 3.3.7 SURFACE FINISH The spring shall be free from cracks. Surface inspection by visual or magnetic defect examination techniques shall be carried out
12、 in the unpainted state if stated on the drawing. The maximum depth of surface imperfections shall be 0.15 mm. 3.3.8 USE OF CONTINUOUSLY CAST (CONCAST) STEEL The general use of concast (as opposed to ingot cast) steel shall be restricted to a final product which has undergone an area reduction ratio
13、 of at least eight to one. For reduction ratios of less than eight to one, down to six to one; only steel supplied by a concaster approved for this purpose by Materials Engineering, Product Development is permitted. 3.3.9 TENSILE STRENGTH (MPa) Strength ranges have been listed for the various grades
14、 and sizes. The procedures for mechanical testing shall be in accordance with the requirements of ASTM E8M. Wire Diameter Steel (mm) A1 A2 & A3 A4 8 - 10 1300-1450 1380-1550 1700-1860 10 11.5 1260-1420 1350-1520 1670-1810 11.5 - 16.0 1240-1400 1300-1490 1640-1780 ENGINEERING MATERIAL SPECIFICATION W
15、SD-M1A310-A1/A4 Page 4 of 4 Copyright 2002, Ford Global Technologies, Inc. 4. GENERAL INFORMATION The information given below is for clarification and assistance in meeting the requirements of the specification. Shot Peening ) To be specified Surface Coating ) on the Engineering Scragging ) drawing or in the Fatigue Requirement ) Engineering Hardness ) Specification Crack Detection ) (if required) ) 4.1 TYPICAL HARDNESS LEVELS A typical minimum hardness level to be expected for the A4 steel grade (see 3.3.9) is 47 HRC. This figure is for impressions taken on sections at the mid-radius.
