某材料为球墨铸钢的粗轧机水平辊在使用很短时间后即发生径向开裂，采用宏观检验、化学成分分析、硬度试验、金相检验等方法对水平辊的开裂原因进行了分析。结果表明：不良的组织状态是导致水平辊开裂的主要原因；水平辊生产过程中未进行高温扩散退火，导致水平辊组织偏析严重，呈枝晶状分布，枝晶间隙碳化物粗大，数量较多，而枝晶杆处部分碳化物呈断续网状分布；另外，铸造过程中钢液石墨化工艺控制不佳，导致石墨数量少，球化效果差。

The horizontal roll of a roughing mill with material of spheroidal graphite cast steel cracked in radial direction after a short time in service. The causes of cracking of the horizontal roll were analyzed by macroscopic inspection, chemical composition analysis, hardness test and metallographic examination. The results show that the poor microstructure was the main reason for cracking of the horizontal roll. High temperature diffusion annealing was not carried out in the production process of the horizontal roll, which resulted in serious segregation and dendritic microstructure of the horizontal roll. The carbides in the dendrite gap were coarse and large in number, and the carbides in dendrite arm were distributed in intermittent reticular form. At the same time, the process control of the molten steel graphitization was poor during the casting process, which resulted in less graphites and poor spheroidization effect.