铬矿砂应用于精密铸造抗粘砂工艺研究

Application of Cr_2O_3·FeO in Investment Casting Heavy Parts

精密铸造滑轮时,采用白刚玉砂(或粉)作为面层涂料时,表面经常产生粘砂缺陷,有时由于粘砂层难以清理而使铸件报废。采用铬铁矿砂(Cr2O3·FeO),代替白刚玉砂作为表面层耐火材料,消除了表面粘砂,同时由于对铸件的厚大部分补缩效果增强,降低了缩孔、缩松缺陷,提高了成品率,分析了铬铁矿砂的作用机理。

Burning-on defects often occurs in surface of investment casting pulley for port machinery when Al2O3 sand(powder)was used as surface layer coating of shell mold,which can result in the discard of the pulley due to not be able to clean.The surface burning-on defects in the investment casting pulley can be eliminated by using Cr2O3·FeO instead of Al2O3 sand(powder)as surface coating of mold shell,meanwhile,Cr2O3·FeO can decrease shrinkage porosity(hole)due to improving feeding effects on thick-large location in the investment casting pulley,increasing qualified product rate.Working mechanism of the Cr2O3·FeO sand was approached.