高镍球铁涡轮增压器壳体针孔缺陷的防止措施

Measures to Prevent Pinhole Defect of High Ni Nodular Iron Turbocharger Housing

分析了高镍球墨铸铁涡轮增压器壳体出现针孔缺陷的原因,从原辅材料、熔炼工艺、覆膜砂壳型设计、浇冒口设计、涂料工艺等方面系统地阐述了高镍球墨铸铁涡轮增压器壳体针孔缺陷的防止措施。最后指出:通过多方面手段可以减少针孔发生的可能性,尤其在单个控制过程发生波动时,能够有效控制针孔缺陷的产生,当防止措施失效、仍发生针孔缺陷时,可以通过添加0.2%~0.4%含锆孕育剂、加入微量铋或硼、局部刷涂激冷涂料的方法,可以紧急防止针孔缺陷产生。

The reason causing vacuum defect of high Ni nodular iron turbocharger housing was analyzed.The pinhole defects prevention measures were systematically described including the raw and auxiliary materials,melting process,resin-coated sand shell mould design,gating and riser design and coating process.Finally pointed out:the possibility of pinhole occurrence could be reduced by multiple means,especially when a single control process fluctuations,generation of pinhole defects could be effectively controlled,when the prevention measures fail and the pinhole defects still occur,the pinhole defects could be urgently prevented by adding 0.2%~0.4%zirconium inoculants,adding micro-amount bismuth or boron,and locally brushing chilling coating.