Four-Point Bending Fracture Behaviors at Low Temperatures of A New 980 MPa High Strength Steel

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 ℃.