某车轮轧制主辊（轧辊）在很短的服役时间内就发生了径向开裂。采用化学成分分析、硬度测试、低倍检验、断口分析、金相检验等方法对轧辊的开裂原因进行了分析。结果表明：该轧辊的化学成分不符合内控要求，且轧辊显微组织不佳，存在枝晶偏析严重，石墨尺寸不均且球化不良，碳化物数量少、不均匀且局部网状等组织缺陷，工作面附近还存在疏松缺陷。不恰当的成分控制，不良的组织状态和内部缺陷使其抗热裂性能和抗热疲劳性能下降，导致轧辊服役极短时间就发生开裂失效。

Radial cracking occurred in the main mill roll in a wheel rolling after a very short service time. The cracking causes of mill roll were analyzed by means of chemical composition analysis, hardness test, macro examination, fracture analysis and metallographic examination. The results show that the chemical compositions of the cracked mill roll did not meet the requirements of internal control, poor microstructure, such as severe dendrite segregation, uneven graph ite size, abnormal nodularizing graphite shape, few and uneven carbides, local carbides network etc, and there were loose defects near the working face. The improper chemical compositions, poor microstructure and internal defects make the hot crack resistance and thermal fatigue resistance of the mill roll decreased, which led to the cracking failure of the mill roll in a very short service time.