S38C车轴钢的旋转弯曲和超声振动疲劳性能

Rotating Bending and Ultrasonic Vibration Fatigue Properties of Axle Steel S38C

选取经硬化(强化)处理的S38C车轴钢小试样,分别采用旋转弯曲疲劳试验机和超声振动疲劳试验机进行疲劳试验,研究其旋转弯曲和超声振动疲劳性能。研究表明,对于具有低温回火马氏体组织的S38C车轴材料,若以4×108周次不发生疲劳破坏的最大应力为疲劳极限,旋转弯曲疲劳试验得到的疲劳极限为775 MPa,超声疲劳试验得到的疲劳极限为675 MPa。通过升降法试验得到(旋转弯曲加载)的具有低温回火马氏体组织的S38C材料在108周次的疲劳极限:对应失效概率10%、置信度95%的疲劳强度下极限为707 MPa;对应失效概率1%、置信度95%的疲劳强度下极限为647 MPa。

The hardening treatment of axle steel S38C small samples were tested by using rotating bending fatigue tes- ting machine and ultrasonic fatigue testing machine to investigate the rotating bending and ultrasonic vibration fatigue properties.The experimental results show that if the maximum value of the stress level at which the fatigue failure does not occur until 4×108 cycles is defined as the fatigue limit, the fatigue limit of $38C sample with the low temperature tempering Martensite microstructure is 775 MPa from rotating bending fatigue test, and 675 MPa from ultrasonic fatigue test.When the cycles is 108, the lower-bound limit of fatigue strength for the S38C by using staircase method is 707 MPa associated with the failure probability 10% and the confidence level 95%, and 647 MPa associated with the failure probability 1% and the confidence level 95%.