宽厚板轧机用Cr3钢支承辊淬硬层深度的理论预测与实验验证

Theoretical prediction and experimental verification of hardened layer depth of Cr3 steel backup roll for heavy plate mill

差温热处理是决定支承辊工作层组织、应力分布和使用性能的关键工序。为精准控制宽厚板轧机用Cr3钢支承辊辊身淬硬层深度以进一步提高其寿命周期内的服役性能,利用ABAQUS有限元模拟软件计算了支承辊在差温热处理过程中的温度场分布,分析了距离辊身不同深度处的温度与显微组织演变,预测了差温处理过程中辊身淬硬层的深度。结果表明:当加热温度达到840℃及以上时,Cr3钢可获得耐磨性较佳的非珠光体组织;Cr3钢支承辊实验件的淬硬层深度达110 mm,表面硬度达到55 HSD以上,且距离表面110 mm深处的硬度降低不大于4 HSD;淬硬层深度的理论预测结果与实测结果吻合较好,可以实现支承辊淬硬层深度的精确控制,指导Cr3钢支承辊差温热处理工艺制定。

Differential heat treatment is a key process that determines the microstructure,stress distribution and service performance of the backup roll working layer.In order to accurately control the hardened layer depth on the backup roll body of Cr3 steel used in the heavy plate mill and further improve its service performance within its life cycle,the temperature field distribution of the backup roll during differential heat treatment was calculated using ABAQUS finite element simulation software.The temperature and microstructure evolution at different depths from the backup roll surface were analyzed,and the hardened layer depth on the backup roll body during differential heat treatment was predicted.The results show that when the heating temperature reaches 840℃or above,Cr3 steel can obtain nonpearlite structure with better wear resistance.The hardened layer depth of the Cr3 steel backup roll experimental piece reaches 110 mm,the surface hardness reaches 55 HSD or above,and the hardness reduction at the depth of 110 mm from the surface is not greater than 4 HSD.The theoretical prediction results of the hardened layer depth are in good agreement with the measured results,which can achieve precise control of the hardened layer depth of the backup roll and guide the formulation of the differential heat treatment process for the Cr3 steel backup roll.