马氏体球墨铸铁磨球的研制和生产应用

The Research on the Martensite Ductile Iron Grinding Balls and Their Industrial Application

采用 1.5t工频感应电炉熔炼铁液 ,经炉前球化孕育处理 ,金属型浇注得到球墨铸铁磨球、配之RT 32 0 9推杆步进式电阻炉加热、水玻璃液模拟等温淬火及低温回火得到的马氏体加贝氏体球墨铸铁磨球 ;其金相组织为 :高碳隐针马氏体 ( 70 %～75 % ) +球状石墨 +上贝氏体 ( 2 5 %～ 30 % ) +少量合金碳化物 ( <5 % ) +少量残余奥氏体 ;其表面硬度为HRC 5 5～ 5 7,表面与心部硬度差HRC≤ 2 ;通过工业性试验平均单耗为 0 .6 6kg/t原矿、破碎率 <1%。

Adopting and electric induction furnace ,50 Hz in frequency and 1.5 t in capacity, cast iron liquid can be obtained. With further treatment like grain refining, graphite spheroidizing and metallic molds application, the ductile iron grinding balls are produced. By using electric resistance furnace and sodium silicate martempering technique, the improved microstructure of the cast iron balls is with 70%～75% high carbon martensite, nodular graphite, 25%～30% bainite and a little amount of carbide and residual austenite. The surface hardness of the balls can be as high as 55-57 in HRC, with only 2 units of hardness variation across the section of the balls. The industrial verifying test shows that the ball wearing rate can be at 0.66 kg per ton of ore rock, and the ball fracturing rate is under 1%.