【摘要】 研究了中碳贝氏体钢支承辊滚动接触疲劳垂直裂纹早期萌生、扩展直至形成深层剥落的全过程,用透射电镜观察了支承辊钢的微观组织,结合其微观组织和力学性能,分析了垂直裂纹萌生机理,发现其形成是由微凸体接触区后边缘的最大拉应力引起的。试验结果表明,降低表面粗糙度可防止垂直裂纹的早期形成。该结果已经应用在支承辊维护实践中,降低了必需的磨削速率,延长了支承辊的有效使用寿命。更多还原

【Abstract】 The whole rolling contact fatigue (RCF) failure process from the early initiation of vertical cracks in medium carbon bainitic steel backup roll to deep spalling was investigated. The microstructures of the steel were studied based on observations using transmission electron microscopy (TEM). According to the microstructure and mechanical properties of the steel,the initiation mechanism of vertical cracks was clarified. It was found that it is the maximum tensile stress occurring at the trailing edge of asperity contact patch that caused the early nucleation of them. It can be deduced from RCF experiment results that the early formation of vertical cracks can be prevented through reducing surface roughness. According to the results,the backup rolls have been properly maintained,that is to say,the required grinding rates have been decreased and their effective service lives have been prolonged considerably.更多还原