Abstract: According to the bar line in hardness value of steel 42CrMo φ50 mm rolled bar too large can not meet the requirements of agreement, through controlled rolling and controlled cooling combined with cooling bed heat preservation measures to decrease the finishing rolling temperature from original 967~970 °C to 860 °C , and reduce the cooling rate from original 0.35 °C to 0.17 °C/s,and optimize the metallographic structure from the previous non-equilibrium phase bainite + ferrite + pearlite to ferrite + pearlite, the HB hardness value of steel decreases from original 317 to 252. Therefrom,the φ50 mm rolled bar produced by this process has good comprehensive mechanical properties.

摘要： 根据棒材线在生产42CrMo钢φ50 mm轧材容易造成硬度偏高，不能满足协议要求。通过控轧控冷结合冷床保温措施,終轧温度由原967～970 ℃降到860 ℃，冷却速率由原0.35℃/s降低到0.17℃/s,金相组织从之前的非平衡态组织贝氏体+铁素体+珠光体优化为铁素体+珠光体，使HB硬度值由原317降至252。由此工艺生产的φ50 mm轧材具有良好的综合力学性能。

关键词: 42CrMo钢, 控轧控冷, 冷床保温, 力学性能