支承辊材料45Cr4NiMoV钢高温临界损伤值测定方法与试验

Research on the method and experiment to determine critical damage value of backup roll material 45Cr4NiMoV steel in high temperature

45Cr4NiMoV钢是大型支承辊的重要材料,其热态成形过程中容易产生裂纹缺陷。深入研究该零件的裂纹形成机理,并对其进行精确预测具有重要意义,而材料的临界损伤值是预测该零件高温裂纹的重要判据。文章基于Normalized Cockcroft&Latham损伤模型,对临界损伤值的实验测定方法进行了理论分析与研究,采用GFL(Gleeble Fracture Limit)方法对45Cr4NiMoV钢高温临界损伤值进行了测定。实验测得,在变形温度为1100℃、应变速率为0.01s-1的条件下,45Cr4NiMoV钢的临界损伤值为0.63。

The crack of 45Cr4NiMoV steel which is used commonly for backup roll happens easily in the hot forming of roll part.Method for determining the critical damage value which is important for predicting the high-temperature fracture of backup roll was studied theoretically based on Normalized Cockcroft Latham damage model.The GFL（Gleeble Fracture Limit） method was adopted for measurement.The test result shows that under the condition of 1100℃ and 0.01s-1 strain rate,the critical damage value of 45Cr4NiMoV steel is 0.63.