1、 ENGINEERING MATERIAL SPECIFICATIONDate Action Revisions 2005 05 24 Activated R. Thomas Printed copies are uncontrolled Copyright 2005, Ford Global Technologies, LLC Page 1 of 4 ALUMINUM, HIGH TEMPERATURE. EUTECTIC SILICON COPPER NICKEL WSS-M2A137-B7 MAGNESIUM ALLOY 1. SCOPE The material defined by
2、this specification is a eutectic silicon aluminum alloy suitable for permanent mold casting, which contains copper, nickel and magnesium to enhance elevated temperature properties. This material is an anodizing grade. 2. APPLICATION This material specification was released originally for automotive
3、gasoline engine pistons where mechanical properties at elevated temperature, dimensional stability and wear resistance are required. This material should not be used in applications where any measurable amount of ductility is required. Due to the higher silicon content, this material will be more di
4、fficult to machine than standard structural aluminum alloys. 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 SAMPLING LOCATIONS Sampling locations
5、 for requirements of this specification shall be as specified on Engineering Drawing, Engineering Specification or in suppliers control plan. For pistons, microstructure-sampling locations shall include the pin bore region, which is generally the slowest solidifying with the coarsest silicon particl
6、e size; and may also include ring groove(s) and skirt(s). Tensile test bars shall be taken from the crown region near the pin bore or other approved location. 3.3 CASTING QUALITY (ASTM E 155 or Approved Alternate) The finished component shall be free from laps, cold shuts, dross and sludge; and shal
7、l have minimal eutectic segregation/depletion. Shrinkage and gas porosity shall be kept to a minimum and any porosity present shall not adversely affect the function of the component. Radiographic assessment levels for gas and shrinkage porosity, if required, shall be according to methods of ASTM E
8、155 and requirements defined on the Engineering Drawing or Engineering Specification. ENGINEERING MATERIAL SPECIFICATIONWSS-M2A137-B7 Printed copies are uncontrolled Copyright 2005, Ford Global Technologies, LLC Page 2 of 4 3.4 CHEMICAL COMPOSITION (Weight Percent) (ASTM E 1479/ASTM E 1251) Silicon
9、11.5 13.5 Copper 3.0 4.0 Iron 0.70 max.* Magnesium 0.7 - 1.3 Nickel 1.7 2.5 Manganese 0.1 - 0.5 Zinc 0.3 max. Titanium 0.25 max. Chromium 0.10 max. Sodium 0.002 max. Strontium 0.002 max. Calcium 0.002 max. Phosphorus * Others Each 0.1 max. Others Total 0.5 max. Aluminum Balance * High performance pi
10、stons may require lower iron. Mn content, in the ratio Fe:Mn 2:1, must balance iron content, if casting process produces parts with beta iron phase (needle-like iron-rich phase) in the microstructure when Mn content is less than one-half the iron content. * Primary silicon refinement 0.0025 0.0200%
11、P typical Supplied composition shall fall within above ranges; limits defined as part of control plan. Customer and supplier shall agree upon test method(s) for molten Aluminum and component chemical analysis determination. ASTM E1479 Inductively Coupled Argon Plasma Spectroscopy (ICP) is recommende
12、d for components and ASTM E 1251 Optical Emission Spectroscopy (OES) is recommended for molten aluminum. Control plan will also include any metal treatment practice (i.e., modification, refining elements, filtering, etc.) and processing detail. 3.5 MECHANICAL PROPERTIES (From Heat Treated Castings o
13、r Finished Components) (ASTM E 8/E 8M/ASTM B 557; ASTM E 10/ISO 6505 and ASTM E 18/ISO R 80) 3.5.1 Tensile Strength, MPa, min. 260 Yield Strength, MPa, min. 240 3.5.2 Hardness, HBW (500 kg load, 10 mm ball), or 90 - 140 (250 kg load, 5 mm ball) Rockwell F, Rockwell B or Rockwell K measurements may b
14、e used on the finished component in lieu of Brinell impressions. Hardness measurement requirements and locations shall be as specified on the engineering drawing. ENGINEERING MATERIAL SPECIFICATIONWSS-M2A137-B7 Printed copies are uncontrolled Copyright 2005, Ford Global Technologies, LLC Page 3 of 4
15、 3.6 MICROSTRUCTURE (ASTM E 3) Microstructure shall consist of primary silicon crystallites in an acicular (needle-like) aluminum silicon matrix containing uniformly distributed intermetallic compounds. Grain size of primary aluminum, size and distribution of silicon, copper and intermetallic compou
16、nds shall be suitable to produce a consistent anodized surface. Specific requirements for anodizing, if required, will be as specified in one or more of the following documents: WSS-M4P12-A1, Engineering Drawing or Engineering Specification. Silicon particles must be randomly distributed and average
17、 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 silicon crystals should be kept to a minimum. 3.7 T6 HEAT TREATMENT A T6 heat treatment shall be used to improve pr
18、operties and dimensional stability; and meet all requirements of this specification. All times shown below are time-at-temperature for casting (not furnace temperatures). Select a solution temperature between 495 515 C and hold for a minimum of one hour prior to water quenching. Select an aging temp
19、erature between 195 240 C. Artificially age castings at the selected temperature for 4 - 8 hours. Selected solution/aging temperature must be maintained at +/- 5 C for duration of cycle. Heat treatment shall be in accordance with Ford Global Manufacturing Standard W-HTX, Control of Heat Treating Pro
20、cesses and Auxiliary Equipment. Specific heating/cooling and aging practice or any deviation to the above shall form part of the supplier control plan and any deviation from the requirement above must be specified on the Engineering Drawing. 4. GENERAL INFORMATION The information given below is prov
21、ided for clarification and assistance in meeting the requirements of this specification. 4.1 REFERENCE DOCUMENTS The following documents are referenced in this specification: ASTM E 228 ASTM B 557 ISO 6506 WSS-M4P12-A1 ASTM E 3 ASTM E 1251 ASTM E 155 WSS-M99P1111-A ASTM E 8 ASTM E 1461 ASTM E 18 For
22、d W-HTX ASTM E 10 ASTM E 1479 ISO R 80 4.2 SUBJECT REFERENCES None 4.3 ALTERNATING BENDING STRENGTH at 250 C, MPa, min. 60 (RANGE 60 70) at 350 C, MPa, min. 40 (RANGE 40 48) ENGINEERING MATERIAL SPECIFICATIONWSS-M2A137-B7 Printed copies are uncontrolled Copyright 2005, Ford Global Technologies, LLC
23、Page 4 of 4 4.4 MODULUS OF ELASTICITY, GPa, Value at 20 C 87 (Range 87 90) Value at 200 C 52 (Range 43 68) 4.5 POISSONS RATIO 0.33 4.6 COEFFICIENT OF LINEAR THERMAL EXPANSION AT 25 C, (RANGE 18 20) (ASTM E 228, 10E-6 Ke-1) 4.7 THERMAL CONDUCTIVITY AT 25 C, W/m Ke-1 130 (ASTM E 1461) 4.8 DENSITY AT 2
24、5 C, g/cm32.77 (ASTM B 311) 4.9 TYPICAL RESIDUAL HARDNESS, HBW (500), 87 AFTER 100 HOURS OF AGING AT 250 C 4.10 MICROWELDING START TEMPERATURE Microwelding of the piston top ring groove surface to the top ring can start at a temperature as low as 150 C on an unanodized surface. Anodizing piston will usually eliminate microwelding. Refer to Ford Engineering Specification WSS-M4P12-A1, Anodized (Anodic) Coating for Cast Aluminum, Electrolytic Type, Hard for more details.
