Patent ID: 9194029
Filing Date: 2015-11-24
Classification: B21J,B21K,B22D,C22C,C22F

Abstract:
1. A production method of an aluminum alloy cast member, the method comprising: a step of obtaining an aluminum alloy melt having an alloy composition consisting of Fe: 0.2 to 0.35 mass %, Cu: 0.05 to 0.20 mass %, Mn: 0.3 to 0.6 mass %, Mg: 1.3 to 2.0 mass %, Zn: 4.6 to 5.1 mass %, and Zr: 0.1 mass % or more, a sum of Zr and Ti being 0.2 mass % or less, the composition satisfying a relation of ([Mg mass %]≧−0.5×[Zn mass %]+3.8) and a relation of ([Ti mass %]/[Zr mass %]≧0.2), and the balance being aluminum and inevitable impurities; a step of obtaining an aluminum alloy ingot having a structure that has a secondary dendrite arm spacing (DAS) of 40 μm or less and an average crystal grain diameter of 8 μm or less by continuously casting the aluminum alloy melt at a casting rate satisfying a condition of ([maximum casting rate (mm/min)]≦−1.43×casting diameter (mm)+500); and a step of obtaining an aluminum alloy cast member by subjecting the aluminum alloy ingot to a homogenization treatment for holding the ingot for 1 hour at a temperature of 450 to 600° C.