1、 ENGINEERING MATERIAL SPECIFICATION Date Action Revisions Rev. 2 2015 01 30 Revised See Summary of Revisions G. Weber, NA 2014 12 17 Released Added A4 G. Weber, NA 2013 08 22 Released A1, A2, A3 G. Weber, NA Controlled document at www.MATS Copyright 2015, Ford Global Technologies, Inc. Page 1 of 5 A
2、LUMINUM CASTING ALLOY, CYLINDER HEAD, LIGHT DUTY WSS-M2A178-A1 ALUMINUM CASTING ALLOY, CYLINDER HEAD, NORMAL DUTY WSS-M2A178-A2 ALUMINUM CASTING ALLOY, CYLINDER HEAD, HEAVY DUTY, DIESEL WSS-M2A178-A3 ALUMINUM CASTING ALLOY, CYLINDER HEAD, HEAVY DUTY, GASOLINE WSS-M2A178-A4 1. SCOPE The materials def
3、ined by these specifications are heat treated aluminum-silicon casting alloys. 2. APPLICATION These specifications were originally released for materials used in manufacture of permanent mold cast cylinder heads. A1 is artificially over-aged aluminum-silicon-copper-magnesium alloy for light duty gas
4、oline engine applications. A2 is solution treated and artificially over-aged aluminum-silicon-copper-magnesium alloy for normal duty gasoline engine applications. A3 is solution treated and artificially aged premium aluminum-silicon-copper-magnesium alloy for heavy duty diesel engine applications. A
5、4 is solution treated and artificially aged premium aluminum-silicon-copper-magnesium alloy for heavy duty gasoline engine applications. 3. REQUIREMENTS 3.1 STANDARD REQUIREMENTS FOR PRODUCTION MATERIALS Material suppliers and part producers must conform to the Companys Standard Requirements for Pro
6、duction Materials (WSS-M99P1111-A). 3.2 CHEMICAL COMPOSITION (Weight Percent) (ASTM E1479/ ASTM E1251) A1 A2 A3 A4 Silicon, Si 6.0 8.5% 6.0 8.5% 6.5 7.5% 6.5 7.5% Copper, Cu 2.8 4.0% 2.8 4.0% 0.40 0.60% 0.40 0.60% Iron, Fe 0.80% max 0.80% max 0.20% max 0.20% max Magnesium, Mg 0.20 0.60% 0.20 0.60% 0
7、.20 0.45% 0.20 0.45% Nickel, Ni 0.30% max 0.30% max - - Manganese, Mn 0.60% max 0.60% max 0.15% max 0.15% max Zinc, Zn 0.80% max 0.80% max 0.10% max 0.10% max Titanium, Ti 0.25% max 0.25% max 0.25% max 0.25% max Lead, Pb 0.15% max 0.15% max - - Tin, Sn 0.10% max 0.10% max - - Strontium, Sr 60 200 pp
8、m 60 200 ppm 60 400 ppm 60 400 ppm Calcium, Ca - - 20 ppm max 20 ppm max Phosphorus, P - - 15 ppm max 15 ppm max Others (Each) 0.05% max 0.05% max 0.05% max 0.05% max Others (Total) 0.25% max 0.25% max 0.15% max 0.15% max Aluminum Balance Balance Balance Balance Mn:Fe Ratio 1:2 min 1:2 min 1:2 min 1
9、:2 min ENGINEERING MATERIAL SPECIFICATION WSS-M2A178-A1/A2/A3/A4 Copyright 2015, Ford Global Technologies, Inc. Page 2 of 5 The composition shall be selected from within the above range. Specific composition limits and foundry practice to meet performance and manufacturing requirements will form par
10、t of the Control Plan for each individual component geometry and supplier. Ford and the supplier shall agree upon the test method(s) used for performing chemical analysis of molten aluminum or cylinder head castings. The recommended method is optical emission spectroscopy (OES) (ASTM E1251), but ind
11、uctively-coupled argon plasma spectroscopy (ICP) (ASTM E1479) may be used for research and failure analysis. In case of dispute over OES results, ICP shall be used as an umpire method. 3.3 HEAT TREATMENT (Ford W-HTX, ASTM B917) Components shall be subjected to heat treatment as defined below, to ach
12、ieve the required mechanical properties and dimensional stability. A1 T5-type treatment consisting of controlled cooling from casting temperature followed by artificial over-aging to stabilize the casting A2 T7-type treatment consisting of cooling from casting temperature, solution treatment, contro
13、lled quenching from solution treatment temperature and artificial over-aging the casting to a substantially stable condition A3/A4 T6-type treatment consisting of cooling from casting temperature, solution treatment, controlled quenching from solution treatment temperature, and artificial aging to a
14、chieve maximum fracture resistance 3.3.1 Engineering Drawing Requirements Heat treatment parameters, including the appropriate quench medium, must be designed to achieve the required mechanical properties and dimensional stability, and determined individually for each component. As appropriate for t
15、he required heat treatment process, the following process parameters shall be fully specified on the Engineering Drawing and reflected in the Supplier Control Plan, which is agreed upon between Ford and the supplier: Solution treatment temperature range and time at temperature range Maximum delay be
16、tween solution treatment and quenching Quench medium Controlled air cooling parameters Minimum quench temperature and hold time Artificial aging temperature range and time at temperature range 3.3.2 Restrictions A2 When a liquid quenching medium is used, the temperature of the quenchant at the begin
17、ning of quenching shall be not less than 90 C. A3 & A4 When a liquid quenching medium is used, the temperature of the quenchant at the beginning of quenching shall be not less than 60 C. 3.3.3 Air Quenching Air quenching may be an acceptable alternative to liquid quenching for some applications, in
18、which case details of the air quench process shall be included in the heat treatment process parameters. ENGINEERING MATERIAL SPECIFICATION WSS-M2A178-A1/A2/A3/A4 Copyright 2015, Ford Global Technologies, Inc. Page 3 of 5 3.4 CASTING QUALITY The cylinder head casting shall be free from laps, cold sh
19、uts, dross, and sludge, and shall have minimal eutectic segregation/depletion. Radiographic and metallographic assessment for gas porosity and shrinkage shall meet the general requirements defined below, and may be further restricted in the Engineering Specification. Evaluation locations shall be de
20、fined in the Engineering Specification. 3.4.1 Radiographic Assessment (ASTM E155) Radiographic assessment for gas holes, gas porosity and shrinkage porosity shall be performed according to methods described in ASTM E155. An assessment of Severity Level 3 or better is required for all defect types. 3
21、.4.2 Metallographic Assessment The volume percent porosity shall be determined by image analysis over an area of 25 square millimeters, on contiguous fields of view, at a recommended magnification of 100X, and shall meet the requirements stated below in critical areas. Critical areas on the casting
22、shall be defined in the Engineering Specification. Maximum size, minimum spacing and maximum grouping shall be specified in the Engineering Specification. A1 & A2 The average volume percent porosity shall be 1% maximum, and no single area shall exceed 1.5%. A3 & A4 The average volume percent porosit
23、y shall be 0.2% maximum, and no single area shall exceed 0.5%. 3.5 MICROSTRUCTURE (ASTM E3) The microstructure shall consist of primary alpha aluminum, alpha aluminum-silicon eutectic, and intermetallic constituents. Efforts should be made to minimize copper segregation and needle-like intermetallic
24、s. Any needle-like intermetallics present in the microstructure shall not exceed 0.75 mm in length. The silicon component of the eutectic shall be modified to meet a minimum level of modification. AFS eutectic modification of Level 4 or better is required in critical areas, and Level 3 or better in
25、non-critical areas. Evaluation locations shall be defined in the Engineering Specification. 3.5.1 Secondary Dendrite Arm Spacing The Secondary Dendrite Arm Spacing (SDAS) shall be computed as the average of 10 primary dendrites at 100X magnification, and shall meet the requirements stated below. Cri
26、tical areas on the casting shall be defined in the Engineering Specification. All other areas are deemed non-critical. A1 A2 A3 A4 Critical Areas Average SDAS, micrometers, max 30 30 25 30 Individual SDAS, micrometers, max 45 45 35 45 Non-Critical Areas Average SDAS, micrometers, max 60 60 50 60 Ind
27、ividual SDAS, micrometers, max 75 75 65 75 ENGINEERING MATERIAL SPECIFICATION WSS-M2A178-A1/A2/A3/A4 Copyright 2015, Ford Global Technologies, Inc. Page 4 of 5 3.6 MECHANICAL PROPERTIES (As Heat-Treated Components) Test samples shall be machined from the component casting, after the appropriate heat
28、 treatment as described in section 3.3. Locations, frequency, and procedures of testing shall be outlined in the Engineering Specification and reflected in the supplier Control Plan, which is agreed upon between Ford and the supplier. Elongation shall be determined by extensometer measurement. A1 A2
29、 A3 A4 3.6.1 Tensile Properties (ASTM B557) Deck Face Tensile Strength, MPa, min 230 230 280 260 0.2% Offset Yield Strength, min 175 200 220 190 Elongation, % min 1.0 1.0 4.0 3.0 Bolt Boss Tensile Strength, MPa, min 200 230 250 240 0.2% Offset Yield Strength, min 170 180 190 180 Elongation, % min 0.
30、5 0.5 3.0 2.0 3.6.2 Compressive Yield Strength, 180 180 190 180 0.2% Offset, MPa, min (ASTM E9) 3.6.3 Shear Strength, MPa, min 160 170 180 170 (ASTM B769) 3.6.4 Hardness, HBW (F/D2 = 10 recommended) (ASTM E10 / ISO 6506) Deck Face 85 - 120 85 120 85 120 85 120 All Other Locations 80 min 80 min 75 mi
31、n 75 min Reporting of Brinell hardness measurements shall include the ball diameter (in mm) and the load (in kgf) used to measure the hardness, as required by the referenced test standards. For example, hardness measured using a 10 mm ball and 500 kgf load would be reported as HBW 10/500. 3.7 CONTRO
32、L OF MANUFACTURING PROCESS Ford Global Manufacturing Standard W-CMS defines a minimum set of required process controls for various casting processes. The casting process shall meet the requirements of W-CMS for Aluminum Permanent Mold processes. Ford Global Manufacturing Standard W-HTX defines a min
33、imum set of required process controls for various heat treatment processes. The specified heat treatment process shall meet the requirements of W-HTX for Aluminum Alloy Solution Heat Treating/Age Hardening. ENGINEERING MATERIAL SPECIFICATION WSS-M2A178-A1/A2/A3/A4 Copyright 2015, Ford Global Technol
34、ogies, Inc. Page 5 of 5 4. GENERAL INFORMATION The information given below is provided for clarification and assistance in meeting the requirements of these specifications. Contact for questions concerning Engineering Material Specifications. 4.1 TYPICAL HEAT TREATMENTS Descriptions of typical heat
35、 treatments to meet the requirements of these specifications are given below. These descriptions are not intended to be requirements, but rather guides to illustrate the information that is required to appear on the Engineering Drawing. Heat treatment parameters, including the appropriate quench med
36、ium, must be designed to achieve the required mechanical properties and dimensional stability, and determined individually for each component. A1 Controlled air cooling to achieve 90C max in less than 30 minutes Temperature at the start of controlled cooling: 475 +/-25 C Artificial aging: 220 +/-5 C
37、 for 3-4 hours A2 Solution treatment: 490 +/-5 C for 4-5 hours Quench Delay: 30 seconds maximum from furnace opening Quench: Water quench at 90 C minimum for 5 minutes minimum Artificial aging: 247 +/-5 C for 3-3.5 hours A3 Solution treatment: 525 +/-5 C for 4-5 hours Quench: Fan-assisted air coolin
38、g to 200 C in less than 5 minutes Artificial aging: 150 +/-5 C for 4-5 hours A4 Solution treatment: 525 +/-5 C for 5-6 hours Quench: Fan-assisted air cooling to 200 C in less than 5 minutes Artificial aging: 160 +/-5 C for 4-5 hours 4.2 CRITICAL AREAS Critical areas of the casting are generally defi
39、ned as those locations were maximum material properties are required, such as the head deck face and bolt bosses. The component engineer, in cooperation with the materials engineer, is responsible for determining and designating critical areas on a casting. All areas deemed critical shall be defined in the Engineering Specification. 5 SUMMARY OF REVISIONS 2014 12 17 Added A4 specification. 2015 01 30 Updated SDAS and hardness on A4 specification. Increased Maximum Sr for A1 and A2.
