支承辊淬硬层条带状疲劳裂纹的扩展动力研究

摘要

支承辊淬硬层内部条带状疲劳裂纹的形成以及由此引起的大面积剥落是支承辊危害最大的失效形式之一。本文通过对淬硬层应力状态的计算分析得出径向残余拉应力是条带状疲劳裂纹主要扩展动力的结论，并进行了疲劳裂纹扩展实验验证。在保证使用性能前提下降低支承辊淬硬层残余应力水平有利于遏制条带状疲劳裂纹发展。%One of the most harmful failure types for backup roll are the stripped fatigue cracks appeared in the quench-hardened layer and the widespread spalling caused by the fatigue cracks .By calculating and analyzing the stress state of quench-hardened layer , the conclusion that the radial residual stress is mainly the propagation motivity of stripped fatigue cracks has been obtained .Meanwhile , the experimental verification for fatigue crack propagation has been performed .Under the condition to ensure the operational performance , reducing the residual stress in the quench-hardened layer of backup roll is beneficial to keep the propagation of stripped fatigue cracks with limits .