用铬铁矿砂提高消失模磨球的耐磨性

Using Chromite Sand to Improve Wear Resistance of Lost Foam Cast Grinding Balls

分析了采用干石英砂作为型砂的消失模负压铸造工艺生产磨球力学性能和耐磨性差的原因。为提高磨球的耐磨性,采用铬铁矿砂取代干石英砂。试验结果表明:由于铬铁矿砂的蓄热系数及导热系数远高于石英砂,而且铬铁矿砂铸型表面硬度较高,因此所生产的磨球的冲击韧性值由5.17J/cm2增大到5.70J/cm2;而相对耐磨性则是石英砂磨球的1.24倍。

The reason why the grinding balls produced by using lost foam-vacuum casting process and with dry quartz sand as molding sand have poor mechanical properties and wear resistance was analyzed.In order to improve the wear resistance of grinding balls,the chromite sand was adopted as the substitute for dry quartz sand.The test results showed that,since both the heat-accumulating factor and heat conducting factor of the chromite sand is much higher than that of the quartz sand,and further more,the surface hardness of the chromite sand mold is relatively higher,therefore the impact toughness of the chromite sand balls was increased from former 5.17 J/cm2 to 5.70 J/cm2,and their relative wear resistance reached 1.24 times of that of quartz sand balls.