1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2003 09 12 Revised Para 3.0 inserted; para 3.1, 3.6 and 4 deleted 2001 04 30 Revised Revised 1, 2, 3 iron content must be balanced by Mn content, 2:1 respectively, if casting process produces parts with beta iron phase (needle-like iron-rich p
2、hase) in the microstructure when Mn content is less than one-half the iron content. * Primary silicon refinement 0.0025 - 0.02% typical Supplied composition shall fall within the above ranges, and limits will be defined as part of the control plan. The control plan will also include modification, re
3、fining elements and processing detail. ENGINEERING MATERIAL SPECIFICATIONWSS-M2A137-B6Printed copies are uncontrolled Copyright 2003, Ford Global Technologies, Inc. Page 2 of 2 3.3 MECHANICAL PROPERTIES (From Heat Treated Castings) Room Temperature 3.3.1 Tensile Strength, min 200 MPa (ASTM E 8/ E 8M
4、) Test bars may be machined from any location, however, the engineering drawing may designate a higher value for test bars from specified locations within the component. 3.3.2 Hardness 90 - 130 HB (ASTM E 10) (500 Kg load, 10 mm ball), or (250 Kg load, 5 mm ball) Rockwell F or Rockwell B measurement
5、s may be used on the finished component in lieu of Brinell impressions. Hardness measurement locations shall be as specified on the engineering drawing. 3.4 MICROSTRUCTURE (ASTM E 3) Microstructure shall consist of primary silicon crystallites in an acicular aluminum silicon matrix containing unifor
6、mly distributed intermetallic compounds. Silicon particles must be randomly distributed and generally average 10 to 50 microns in diameter, with no edge length of any particle to exceed 100 microns. High performance pistons may require finer silicon particle size. Surface depletion of primary silico
7、n crystals should be kept to a minimum. Microstructural field sampling area and locations shall be as specified in suppliers control plan. For pistons, sampling locations should include pin bore and ring groove. 3.5 HEAT TREATMENT (T5 or T6) Cool from an elevated temperature casting process or solut
8、ion heat treatment and then artificially age to improve mechanical properties and/or dimensional stability. Age for a minimum of 4 hours, typically 8 - 12 hours at temperatures selected between 195 - 240 C. Maintain selected aging temperature to +/- 5 C. Specific heating/cooling and aging practice or any deviation to the above shall form part of the component control plan.
