Aluminum Alloys

The casting of Aluminum Alloys comprises the largest part of O’Fallon Casting’s business. Most common are aluminum-silicon alloys 356 / A356 / 354 / C355 / A357 / F357. These alloys have excellent castability, weldability, pressure tightness and corrosion resistance. They are heat treatable and can be provided in various combinations of physical properties

The most frequently cast aluminum alloys are 356 and its higher purity version, A356. These are good general purpose alloys and because they are in wide use are advantageous in terms of cost and delivery.

  • A357 alloy contains a larger magnesium content than does A356 so can be heat treated to higher strength levels. A357 contains a very small amount of beryllium so does present an inherent safety hazard.
  • F357 is a beryllium free variant of A357 though less strong, is a common substitute for that alloy.
  • C355 alloy contains a larger presence of copper, making it stronger but less ductile than A356. C355 maintains its strength better than other aluminum-silicon alloys at elevated temperatures.
Alloy Reference Spec Castability Heat Treat Condition Tensile Strength (psi) Yield Strength (psi) Elongation Remarks
C355AMS 4215
ASTM B618		Very GoodT637,000
36,000		30,000
25,000		1
2.5		Stronger but less dectile than A356
356AMS4260
ASTM B618		ExcellentT633,000
30,000		22,000
20,000		3
3		Most commonly cast IC alloy
A356AMS 4218
ASTM B618		ExcellentT6
T6		33,000
34,000		27,000
24,000		3
3.5		Good strength & Corrosion Resistance. Excellent machining, welding, plating, or anodizing.
A357AMS 4219Very GoodT641,00032,0003Higher strength thank A356, contains Beryllium
F357AMS 4289Very GoodT641,00032,0003Higher strength thank A356, Beryllium Free
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