TESTING 1-2-3 200-SERIES ALUMINUM CASTING AN MCDP STAFF REPORT C 1
ast aluminum alloys are used in many automotive applica- tions to reduce weight and improve effi ciency and vehicle performance. Some major uses for aluminum alloys include gasoline engine block and cylinder head castings, suspension components and
turbine compressor wheels. T e approximate temperature limit for 354 aluminum heat treated to the T61 temper is 347F (175C). T e maximum operating temperature of most structural aluminum alloys, both cast and forged, is about 392F (200C). Historically, aluminum alloys have scarcely been used above that temperature. T e need for aluminum alloys with improved creep
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42 | METAL CASTING DESIGN & PURCHASING | May/Jun 2012
resistance at increasing temperatures has intensifi ed the search for alloying elements that produce stable precipi- tates. David Weiss, Eck Industries, Manitowoc, Wis., Gerald Gegel, Material & Process Consultancy, Morton, Ill., and Kumar Sadayappan, Materials Technology Labo- ratory, Ottawa, Canada, recently set out to study those alloying elements.
Question How can 200-series aluminum be used to produce qual-
ity castings for high temperature applications?
Background Demands from industrial and military sectors
Breaking down the industry’s latest research papers is as easy as 1-2-3: “Development of Cast Al Alloys for Elevated Temperature (250C) Service” D. Weiss, Eck Industries, Manitowoc, Wis., G. Gegel, Material & Process Consultancy, Morton, Ill., K. Sadayappan, Materials Technology Laboratory, Ottawa, Canada Background—Demands from industrial and military sectors require lightweight alloys that can be used in the 482-572F (250-300C) temperature range. This research effort intended to develop an aluminum-copper-scandium-base alloy for elevated temperature applications.
require lightweight alloys that can be used in the 482-572F (250-300C) temperature range. For example, the need to reduce the exhaust emis- sions of medium- and heavy-duty diesel engines has led to the use of two-stage series turbocharger air system designs. Single stage compres- sors run at an outlet temperature of about 347F (175C) at sea level, which is the approximate temperature limit of the 354-T61 aluminum alloy used for cast impellers. Second-stage outlet air temperatures are predicted to reach 500F (260C) or higher at sea level conditions, and this temperature will increase with operational altitude. T e present research eff ort and
Procedure—Five experimental alloys were prepared. Hardness was tested after heat treatment and long-term exposure. One of the alloys was selected for casting process parameter testing.
Results and Conclusions—The base alloy demonstrated improved elevated temperature strength over other high-temperature alloys and reasonable casting response. The aluminum-copper-scandium-base alloy casts similarly to a 242 alloy and better than 206-type alloys.
paper, “Development of Cast Al Alloys for Elevated Temperature (250C) Ser- vice,” intended to fi nd an aluminum- copper-scandium alloy for elevated temperature applications and determine thermal treatment and optimal casting parameters for the alloy. Ultimately, the alloy will be used to produce a metal matrix composite.
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