Cast aluminum alloy can be divided into 2 categories: general castings and die castings. For general castings, there will be the sand mold, the metal casting mold, and precision casting. According to U.S. AA specification, cast aluminum alloy can be divided into 1xx - 9xx series based on the elements added. For the commonly used Al-Si alloy, the tensile strength can almost reaches 300MPa (depends on the content of Cu). Compared to other series of cast aluminum alloys, both 2xx series (Al-Cu) and 7xx series (Al-Zn) are having higher strengths. Especially for zamak alloy, the tensile strength can almost reach 400MPa.