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利用超声疲劳试验设备对LZ50钢进行变幅疲劳性能的研究同时用扫描电子显微镜(SEM)观察分析了疲劳断口的形貌特征。试验采用荷载步线型累加的加载形式,选取最大荷载σhigh为390 MPa。结果表明:经过小荷载作用后的实验材料其疲劳性能有显著增强,表现出明显的Coaxing效应;引入强化因子对Palmgreen-Miner累积损伤准则进行修正,经修正后的Palmgreen-Miner累积损伤准则能较好地预测材料使用工况下的变幅寿命。
The fatigue properties of LZ50 steel were studied by using ultrasonic fatigue test equipment. Meanwhile, the morphology of fatigue fracture was analyzed by scanning electron microscope (SEM). The test adopts the loading form of load step type accumulation, and the maximum load σhigh is 390 MPa. The results show that the fatigue properties of the experimental materials after the small load increase obviously, and the Coaxing effect is obvious. By introducing the strengthening factor, the Palmgreen-Miner cumulative damage criterion can be corrected, and the modified Palmgreen-Miner cumulative damage criterion can compare Good prediction of luffing life under material usage conditions.