通过化学成分检验、金相分析、及对连铸工序进行调查,分析了转炉冶炼40Cr热轧圆钢表面裂纹的产生原因。结果表明,连铸拉速不稳定是造成裂纹的主要原因。并跟踪分析了一个浇次连铸拉速的控制情况。 Through chemical composition test, metallographic analysis, and the continuous casting process investigation, analysis of the 40Cr hot-rolled bar surface smelting furnace cracking causes. The results show that the instability of casting speed is the main reason of cracks. And tracking analysis of a pouring casting speed control.