1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev 03 2011 12 20 A3 Inactivated/ N Status A4 No replacement named for A3, A4 S. Ryzyi, NA 2007 08 03 Revised Revised 3.2, 3.3, 4.1, 4.3 Inserted 4.5 and added A4 version G. Weber 1999 05 17 Activated J. Daeth, G. Weber Printed copies are unc
2、ontrolled Copyright 2011, Ford Global Technologies, LLC Page 1 of 4 STEEL, FORGING, AIR COOLED MEDIUM CARBON WSS-M1A340-A1 WSS-M1A340-A2 INACTIVE WSS-M1A340-A3 NOT TO BE USED FOR NEW DESIGN WSS-M1A340-A4 1. SCOPE The materials defined by these specifications are medium carbon steels which develop th
3、eir properties upon controlled air cooling from the forging temperature. Both microalloyed 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
4、 and connecting rods. The materials defined by these specifications are not recommended for 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 Productio
5、n Materials (WSS-M99P1111-A). 3.2 CHEMICAL COMPOSITION (Weight Percent) A1 A2 A3 A4 Carbon 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 Phosphor
6、us 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 Molybdenum 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
7、 0.020 - - Carbon Equivalent - - - 1.04 1.10 Carbon Equivalent (C.E.) = %C + 0.28(%Mn) 1.03(%S) + 0.323(%Cr) + 1.69(%V) *When steel for A1 is silicon killed, aluminum shall be 0.015% max. ENGINEERING MATERIAL SPECIFICATION WSS-M1A340-A1/A2/A3/A4 Printed copies are uncontrolled Copyright 2011, Ford G
8、lobal Technologies, LLC Page 2 of 4 3.3 MECHANICAL PROPERTIES (ISO 6892/ASTM E 8M) Mechanical 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 Engineer
9、ing Drawing and/or Engineering Specification, and reflected in the Supplier Control Plan. Tests 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, MP
10、a, min 3.3.3 Elongation, %, min 12 12 10 10 3.3.4 Hardness, HB 223 - 269 255 - 298 269 - 331 262 - 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
11、are permitted. Ferritic grain size shall be ASTM size 4 or finer, with sporadic areas of size 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 c
12、riteria for macroetch testing per ASTM E 381 must be agreed upon between the steel producer 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
13、other conditions defined in the above standard must not be present in the final product. A4: 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 SPECIFICATION W
14、SS-M1A340-A1/A2/A3/A4 Printed copies are uncontrolled Copyright 2011, Ford Global Technologies, 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 proper
15、ties listed previously are to be obtained from parts produced according to the approved Control 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 temper
16、ature to room temperature will tend to degrade the machinability. The finish forging temperature 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 Enginee
17、ring and Manufacturing before their implementation. If the mechanical properties of rough forging 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 co
18、oling rate are to be established for each individual part. 4.2 SUBSEQUENT HEAT TREATMENT (WSS-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 Drawi
19、ng. These applications are all older designs utilizing the A3 grade, and permission for heat 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 treatm
20、ent. 4.3 ROUGH FORGING STOCK (A1, A2, A3) In order to meet the mechanical properties listed 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
21、112) Prior austenite grain size (McQuaid-Ehn test) should be sufficient to meet the ferritic 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
22、112) Because of the dynamic nature of parts produced to this specification, the microcleanliness 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 a
23、re not recommended, though they should be rated and monitored. ENGINEERING MATERIAL SPECIFICATION WSS-M1A340-A1/A2/A3/A4 Printed copies are uncontrolled Copyright 2011, 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.
24、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 STRENGTH 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
25、Control Plan. Test bar location shall be indicated on the appropriate Engineering Drawing and/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.
26、Axial fatigue cycling is conducted at 40 Hz for A1, A2 and A3, and at 50 Hz for A4. For the purposes 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 co
27、nstituted by complete separation of the test bar into two pieces. Discrepancies from the values 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 n
28、ot required to be measured or verified prior to component production. A1 A2 A3 A4 Compressive 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
29、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
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