加载频率对FV520B-Ⅰ钢超高周疲劳性能的影响

摘要

采用超声疲劳试验方法和常规疲劳试验方法,对FV520B-Ⅰ钢在20 kHz和140 Hz频率下的超高周疲劳性能进行了研究,分析了加载频率对FV520B-Ⅰ钢超高周疲劳性能的影响,并基于Basquin方程对超声疲劳试验数据进行了修正.结果表明:在应力幅值相同的情况下,试验钢的疲劳寿命随加载频率的提高而增加,而疲劳强度随加载频率的提高而降低;常规疲劳试验和超声疲劳试验下试验钢的疲劳断裂机制和断口形貌基本相同;修正后的超声疲劳试验数据与常规疲劳试验数据具有较好的相容性.%The super high cycle fatigue property of FV520B-I steel was studied by ultrasonic and conventional fatigue test method with frequency of 20 kHz and 140 Hz,respectively.The influence of loading frequency on super high cycle fatigue property of FV520B-I steel was investigated,and the ultrasonic fatigue testing data was corrected based on Basquin formula.The results show that the fatigue life of FV520B-I steel increased with increase of loading frequency when stress amplitude was the same,while fatigue strength was decreased.The fatigue fracture mechanism and fracture morphology of FV520B-Ⅰ steel in ultrasonic fatigue test were almost the same with that in conventional fatigue test.The corrected ultrasonic fatigue test data had a good compatibility with conventional fatigue test data.