硅对银合金铸造性能的影响

Effect of Silicon on the Castability of Silver Alloy

传统斯特林银合金铸造时容易吸气氧化,流动性较差,有缩松倾向,铸造毛坯件表面容易发黑。研究了硅对银-铜合金铸造性能及其它性能的影响,结果表明,硅可以提高银合金的流动性和充型性能,减少合金的氧化吸气,使铸件表面更光亮,并减少合金的缩松倾向,使合金整体的铸造性能得到改善。但是,硅的加入量要严格限制在一定范围内,过量的硅容易导致铸件出现硬点缺陷,抛光时容易在表面形成划痕,影响抛光效果,而且硅含量高时容易形成低熔点共晶体,增加铸件出现热裂的危险。对斯特林银合金来说,硅量应控制在0.12%以下。

During the casting process, The traditional Sterling silver alloy is prone to absorb air, oxidize and it has poor fluidity, and the tendency of shrinkage porosity in the castings, and is easy to blacken the casting surface. The effect of silicon on the castability and other properties of Ag-Cu alloy was studied, the results show that Si can improve the fluidity and formability of silver-copper alloy, decrease oxidization and absorbing gas, brighten the casting surface, and lower the shrinkage porosity tendency, therefore, it improvethe general castability of silver alloy effectively. However, The adding content of silicon should be limited within a certain range, once the adding content of silicon was excessive, it would easily result in hard spots in the casting, which would cause scratching mark and impair the polishing effect. Morever, when high Si content would form eutectic phase with low melting point and increased the risk of hot crack in the final casting. The results show that Si should be controlled within 0.12% for sterling silver alloy.