(Silicon) good fluidity, improve the ability to charge, in the course of the crystallization of a large amount of heat. With almost no shrinkage, the shrinkage rate of the alloy decreases the tendency of shrinkage cavity, porosity and thermal cracking, and improves the air tightness. The strength is improved after metamorphism, which has abrasion resistance and corrosion resistance. Increasing tensile strength reduces elongation. When the content is 5%, there is fluidity, accounting for 6%, no thermal cracking, accounting for 9%, no looseness