ALUMINUM ALLOY FOR CASTING EXCELLENT IN PRESSURE RESISTANCE

摘要

PURPOSE:To prevent the occurrence of shrinkage cavity due to Fe as an impurity in a casting composed of Al alloy by adding specific small amounts of Ca to an Al-Si-Mg or Al-Si-Mg-Cu alloy for casting. CONSTITUTION:At the time of casting machine parts requiring pressure resistance by using a lightweight Al alloy, Fe is mixed as impurity into Al scrap as a material to be used and, as a result, shrinkage cavities occur in the final solidification part of a casting and pressure resistance is deteriorated. As the above Al alloy, Ca is added by 0.001-0.01% by weight in the form of an Al-Ca master alloy, etc., to an Al-Si-Mg or Al-Si-Mg-Cu alloy containing 4-13% Si and 0.1-2.0% Mg or further containing 5% Cu or 1.0% Mn and/or 3.0% Ni independently or in combination and also containing 0.2-0.8% Fe as an impurity. Since the occurrence of shrinkage cavity due to the presence of Fe is prevented by the addition of Ca, an Al alloy for casting excellent in pressure resistance can be obtained.