1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2007 08 03 Revised Revised 3.2, 3.3, 4.1, 4.3 Inserted 4.5 and added A4 version G. Weber2002 09 19 Revised Updated and renumbered 1999 05 17 Activated J. Daeth, G. Weber Printed copies are uncontrolled Copyright 2007, Ford Global Technologies,
2、 LLC Page 1 of 4 STEEL, FORGING, AIR COOLED MEDIUM CARBON WSS-M1A340-A1 WSS-M1A340-A2 WSS-M1A340-A3 WSS-M1A340-A4 1. SCOPE The materials defined by these specifications are medium carbon steels which develop their properties upon controlled air cooling from the forging temperature. Both microalloyed
3、 and plain carbon steels, which may contain nitrogen, are included. 2. APPLICATION These specifications were originally released for materials used in the manufacture of high durability cycle engine crankshafts and connecting rods. The materials defined by these specifications are not recommended fo
4、r applications involving impact loading. 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 CHEMICAL COMPOSITION (Weight Percent) A1 A2 A3 A4 Carbon
5、 0.36 - 0.40 0.36 - 0.40 0.42 0.47 0.30 0.36 Silicon 0.50 - 0.65 0.50 - 0.65 0.15 0.35 0.15 0.35 Manganese 1.40 1.55 1.35 1.45 1.20 1.40 1.10 1.40 Sulfur 0.050 0.065 0.050 0.065 0.045 0.065 0.080 0.130 Phosphorus 0.025, max 0.015, max 0.035, max 0.035 0.080 Chromium 0.10 0.20 0.10 0.20 - 0.05 0.35 M
6、olybdenum 0.05, max 0.05, max - - Nickel 0.15, max 0.15, max - - Copper 0.25, max 0.25, max - - Vanadium - 0.08 0.12 0.10 0.15 0.23 0.30 Aluminum* 0.006 0.020 0.010 0.030 0.025, max - Nitrogen 0.013 0.020 0.013 0.020 - - Carbon Equivalent - - - 1.04 1.10 Carbon Equivalent (C.E.) = %C + 0.28(%Mn) 1.0
7、3(%S) + 0.323(%Cr) + 1.69(%V) *When steel for A1 is silicon killed, aluminum shall be 0.015% max. ENGINEERING MATERIAL SPECIFICATIONWSS-M1A340-A1/A2/A3/A4 Printed copies are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 2 of 4 3.3 MECHANICAL PROPERTIES (ISO 6892/ASTM E 8M) Mechanic
8、al properties will be measured on test specimens taken from parts produced according to the approved Control Plan. The test specimen and Brinell hardness location shall be indicated on the appropriate Engineering Drawing and/or Engineering Specification, and reflected in the Supplier Control Plan. T
9、ests may be carried out on substandard test specimens if standard specimens cannot be obtained. A1 A2 A3 A4 3.3.1 Tensile Strength, 750 850 900 890 MPa, min 3.3.2 0.2% Offset Yield 450 580 625 700 Strength, MPa, min 3.3.3 Elongation, %, min 12 12 10 10 3.3.4 Hardness, HB 223 - 269 255 - 298 269 - 33
10、1 262 - 363 (ASTM E 10) 3.4 MICROSTRUCTURE (ASTM E 112) The general microstructure, as observed in forged parts, shall be comprised of ferrite and pearlite. No acicular transformation products such as bainite are permitted. Ferritic grain size shall be ASTM size 4 or finer, with sporadic areas of si
11、ze 3 permissible at depths 5 mm or greater below the forged surface. Test location shall be identified on the Engineering Drawing. 3.5 CONTINUOUSLY CAST BLOOMS AND BILLETS (ASTM E 381) A1, A2, A3: Acceptance criteria for macroetch testing per ASTM E 381 must be agreed upon between the steel producer
12、 and forging manufacturer and must be included in the Control Plan. Sufficient reduction ratios and proper control of casting temperature should be part of the Control Plan. Evidence of dendritic structure or other conditions defined in the above standard must not be present in the final product. A4
13、: Acceptance criteria for macroetch testing per MES MM010A must be agreed upon between the steel producer and forging manufacturer and must be included in the Control Plan. ENGINEERING MATERIAL SPECIFICATIONWSS-M1A340-A1/A2/A3/A4 Printed copies are uncontrolled Copyright 2007, Ford Global Technologi
14、es, LLC Page 3 of 4 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of this specification 4.1 THERMAL RESPONSE The mechanical properties listed previously are to be obtained from parts produced according to the approved Cont
15、rol Plan. The finish forging temperature and cooling cycle have a strong influence on mechanical properties of a part. The cooling cycle also has an effect on machinability. Faster cooling from forging temperature to room temperature will tend to degrade the machinability. The finish forging tempera
16、ture and cooling cycle should therefore be included in the Control Plan. Changes in either finish forging temperature or cooling cycle made after the start of series production should be reviewed with Engineering and Manufacturing before their implementation. If the mechanical properties of rough fo
17、rging stock are to be checked, testing shall be conducted on standard test pieces produced from forging stock which has been hot reduced and cooled under controlled conditions. The percentage reduction and cooling rate are to be established for each individual part. 4.2 SUBSEQUENT HEAT TREATMENT (WS
18、S-M1A340-A3 only) For certain applications, heat treatment, by hardening and tempering after forging, is permissible to achieve the mechanical properties listed above or as identified on the Engineering Drawing. These applications are all older designs utilizing the A3 grade, and permission for heat
19、 treatment shall be noted on the Engineering Drawing. New designs using this material shall develop the appropriate mechanical and microstructural requirements upon air cooling, without subsequent heat treatment. 4.3 ROUGH FORGING STOCK (A1, A2, A3) In order to meet the mechanical properties listed
20、previously, and to insure the use of good quality steel, rough forging stock should have the following properties. These items should be included in the Control Plan. 4.3.1 Prior Austenite Grain Size (ASTM E 112) Prior austenite grain size (McQuaid-Ehn test) should be sufficient to meet the ferritic
21、 grain size requirements of the finished forging as specified above. Generally, a prior austenite grain size of ASTM 5 or finer is recommended. 4.3.2 Non-metallic Inclusion Content (ASTM E 45 Method A/ASTM E 112) Because of the dynamic nature of parts produced to this specification, the microcleanli
22、ness of rough forging stock should be of high quality. The following are recommended maximum JK inclusion ratings. Because of the high sulfur contents of these grades, maximum ratings for sulfide inclusions are not recommended, though they should be rated and monitored. ENGINEERING MATERIAL SPECIFIC
23、ATIONWSS-M1A340-A1/A2/A3/A4 Printed copies are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 4 of 4 4.3.2.1 Aluminum-Killed Steels AT AH BT BH CT CH DT DH - - 2.5 1.5 1.0 0.5 1.5 1.0 4.3.2.2 Silicon-Killed Steels AT AH BT BH CT CH DT DH - - 2.5 1.5 2.5 1.5 1.5 1.0 4.4 FATIGUE STREN
24、GTH at A1 A2 A3 A4 10e7 cycles, MPa, min (ASTM E 466, R = - 1, 270 330 N/A 465 sinusoidal waveform) Fatigue strength is measured on test bars taken from rough forged parts produced according to the approved Control Plan. Test bar location shall be indicated on the appropriate Engineering Drawing and
25、/or Engineering Specification, and reflected in the supplier Control Plan. The frequency of testing will be agreed upon between Product Engineering and the supplier, and clearly defined in the Control Plan. Axial fatigue cycling is conducted at 40 Hz for A1, A2 and A3, and at 50 Hz for A4. For the p
26、urposes of this specification, six specimens are to be machined into test bars and tested. Test specimens will have a circular cross-section with a continuous radius between ends. Test bar failure will be constituted by complete separation of the test bar into two pieces. Discrepancies from the valu
27、es listed above will be reported to the affected Product and Materials Engineering 4.5 INFORMATIVE MATERIAL PROPERTIES (TYPICAL) The following material properties are provided for information only, and are not required to be measured or verified prior to component production. A1 A2 A3 A4 Compressive
28、 Yield 740 Strength, 0.2% Offset, MPa (ASTM E 9) Shear Strength, MPa 510 630 Elastic Modulus, GPa 201 (ASTM E 111) Poissons Ratio 0.28 4.6 STRESS RELIEF OF CRANKSHAFTS (A1 & A2) Stress relief of crankshafts shall not be part of the normal production process, and shall not be performed without prior Engineering authorization. When necessary, crankshafts may be stress relieved using the following heat treatment: A1: 560 620 C for 1 hour at temperature, followed by air cooling A2: 620 C for 1 hour at temperature, followed by air cooling
