一种新型980MPa高强钢的低温四点弯曲断裂行为

摘要

Four-point bending tests for the sample with notch at different temperatures (-196-200 ℃) were performed on a new 980 MPa high strength steel.The fracture surface was observed by scanning electron microscopy.The fracture behaviors of the high strength steel were investigated.The results show that with increasing the test temperature, the toughness of the steel gradually increased.It was ductile fracture at - 100 ℃ or above, and the toughness was good.The fracture feature transformed from ductile fracture to brittle fracture at below -100 ℃.It was brittle quasi-cleavage fracture at -196 ℃.%在不同试验温度(-196～200℃)下对一种新型980 MPa高强钢进行了带缺口试样的四点弯曲试验,并用扫描电镜对其断口进行了观察,研究了该钢的断裂行为.结果表明:随着试验温度升高,该钢的韧性逐步提高;在-100℃及以上温度时,该钢的断裂形态为韧性断裂,韧性较好;在-100℃以下,逐渐由韧性向脆性断裂过渡,在-196℃时,为脆性准解理断裂.