锆砂覆膜砂铸钢件表面缺陷的形成机制及防治措施

论述了锆砂覆膜砂铸钢件表面缺陷的形成机制,就该缺陷的防治措施进行了探讨。认为锆砂覆膜砂铸钢件表面缺陷气痕和流痕形成的主要成因是:再生砂粒度过细、壳型(芯)的透气性偏低,浇注系统不合理、钢液流动不平稳、铸型排气能力差,浇注温度偏低且不稳定等。实践表明,增加壳型(芯)的透气性、采用平稳快速浇注工艺方案、适当提高浇注温度等,可以达到减少和消除锆砂覆膜砂铸钢件气痕和流痕缺陷之目的。

Surface Defects Formation mechanism of Resin-Coated Zircon Sand Steel Castings and Their Prevention Measures

The surface defects formation mechanism of steel castings produced with resin-coated zircon sand mould was described,and their prevention measures were discussed.It was considered that the main reason causing the gas and flow trace defects on the surface of steel castings poured in the resin-coated zircon sand mould are as follows:the grain size of the reclaimed zircon sand was too fine,permeability of the shell moulds(cores)was some lower,the gating system was not proper,the molten steel flow was not smooth,the venting ability of the mould was lower,pouring temperature was too low and pouring flow was not stable,etc.Practice showed that it is possible to reduce or eliminate the gas trace and flow trace defects by increasing the permeability of the shell moulds(cores),adopting fast and smooth pouring process,as well as properly increasing pouring temperature.