镶铸式复合锤头的铸造工艺研究

Research on Cast-in Process of Composite Hammer

分别采用高铬铸铁和碳素钢作为锤端和锤柄。造型时将涂附保护剂的锤柄套上锤端整体放入砂型中,锤端和浇道采用消失模。采用立浇的方式,锤端设置冒口。复合时将砂型整体放入感应线圈中感应加热,锤柄升到一定温度时,开始浇注金属液并继续加热,待金属液完全覆盖锤柄时停止加热,继续浇注直到充满整个冒口。所得的界面为完全冶金结合。复合层经热处理组织为Cr7C3共晶碳化物+马氏体+少量残奥,硬度≥58 HRC,冲击韧度≥12 J/cm2。锤头使用寿命是同等工况下高锰钢的4倍左右。

The cast steel and high chromium cast iron were used respectively as handle and head material of hammer respectively. Lost form method was used for making the composite hammer. The coated hammer handle and foam pattern of hammer-head were placed in the sand mold. Vertical pouring was used and a feeder was placed on the top of the hammer head. The mold with the hammer handle and foam pattern of hammerhead was wholly placed in an intermediate frequency induction heater. When the hammer hand was heated to certain temperature start to pour metal, and induction heating will not stop until the liquid metal covered all handle. Pouring was continued until the cavity of mould was fully filled. The interface of bi-metal is wholly metallurgically bonded. After heat treatment the microstructure of hammer head is Cr7C3 eutectic carbide＋martensiteq-little residual austenitic, HRC≥58, impact toughness≥12 J/cm^2. The service life of the hammer is about four times as long as that of austenitic manganese steel under the same condition.