无缝钢管连轧机限动芯棒热疲劳性能研究

Study on the thermal fatigue behavior of retained mandrel for rolling seamless steel pipe

主要借助于透射电镜研究芯棒的热疲劳行为,并且通过优化热处理工艺来减缓热疲劳裂纹的形成和扩展。研究结果表明,芯棒经冷热疲劳循环后随着循环次数的增加会产生一种循环软化现象,而基体中碳化物的粗化是产生循环软化的主要原因。通过优化材料组织可提高材料的热疲劳性能。

Thermal fatigue behavior of mandrel steel was studied by means of TEM,and the formation and propagation of thermal fatigue cracks were reduced by optimizing the heat treatment process. The results showed that the mandrel steel after thermal fatigue would produce a cyclic softening phenomenon with the increase of the cycle,while the coarsening of the carbides in the matrix was the main reason of cyclic softening. By optimizing microstructure,thermal fatigue performance of the material was improved.