Grain refinement and mechanical properties improvement of casting A357 alloy by high pressure differential pressure casting process
(1.黑龙江省哈尔滨市哈尔滨工业大学材料科学与工程学院2.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: By using conventional differential pressure casting process and high pressure differential pressure casting process respectively, Al-Si-Mg system A357 alloy castings were produced. The results show that compared with the conventional differential pressure casting process, the high pressure differential pressure casting process can further refine grain and improve the tensile strength and elongation of as-cast and heat treated A357 alloy. For as-cast A357 alloy with SiO2 resin sand mould, the increasing scales exceed 6% and 50%, respectively. After heat treatment, the increasing scales exceed 15% and 50% respectively. For as-cast A357 alloy with SiO2-Fe chill mould, the increasing scales exceed 6% and 17% respectively. After heat treatment, the increasing scales exceed 7% and 23% respectively. But the increasing scale depends on the cooling rate of casting. With the increase of the cooling rate, the increasing scale decreases.
Key words: A357 alloy； differential pressure casting； grain refinement； mechanical properties