一种400MPa级铌微合金钢的疲劳性能

Fatigue Behaviour of a 400 MPa Grade Nb Microalloyed Steel

采用四点弯曲疲劳试验研究了应力比为-0.82和-1的含铌微合金钢SQ390的疲劳行为,对疲劳断口进行了SEM分析,用试验结果对Soderberg公式进行了验证。结果表明,试验钢的弯曲疲劳曲线呈直线形,两个应力比下的弯曲疲劳强度分别为275 MPa和256 MPa,疲劳裂纹均起源于试样表面。Soderberg公式对低合金钢四点弯曲疲劳试验结果非常适用。

Flexural behavior of Nb microalloyed steel SQ390 with stress ratio of-0.82 and-1 were investigated by using four-point flexural fatigue experiments.Fracture morphology was observed with SEM and Soderberg formula was demonstrated by experimental results.The results show that flexural fatigue curves of the SQ390 steels presented linear.Flexural fatigue at different stress ratio were 275 and 256 MPa,respectively.Flexural cracks lied at the surface of the SQ390 steels.Soderberg formula was well applicable to the results of four-point flexural fatigue experiments of microalloyed steel.