【摘要】 研究了不同回火温度下40Cr钢的高周疲劳损伤特性.通过损伤量的变化测量和扫描电镜下损伤不同阶段微观组织的观察,分析回火温度对疲劳损伤特性的影响.实验结果表明,结构钢材料在高周疲劳载荷作用下,疲劳损伤过程分为3个阶段,即微孔洞萌生区、微裂纹萌生区、宏观裂纹萌生区.疲劳裂纹的萌生期随着回火温度的升高而增加,在本实验的载荷作用下,高温回火的40Cr钢的裂纹萌生期在3万周以上,中温回火的裂纹萌生在2.8万周,而低温回火的裂纹萌生期在2万周.更多还原

【Abstract】 The high cycle fatigue damage characteristics of 40Cr steels tempered at different temperatures were studied. The influence of tempering temperatures was analyzed by the quantitative measurement of change in damage and the SEM observation of the microstructure at different damage stages. Three stages were identified in the fatigue damage of structural steel materials under high cycle fatigue loading conditions, with the first stage corresponding to the initiation of micro-voids, the second stage to the initiation of micro-cracks, and the third stage to the initiation of macro-cracks. The number of cycles to initiate the fatigue cracks increased with increasing tempering temperatures. Under the loading in the present study, the crack initiation of high temperature tempered 40Cr steels occurred above 30?000 cycles, while that of middle temperature tempered steels occurred at 28?000 cycles, and only 20?000 cycles were needed for the crack initiation in low temperature tempered steels. 更多还原