INFLUENCE OF P ON FRACTURE MORPHOLOGY OF Cr-Mn-Si STEEL WITH PEARLITE, BAINITE AND MARTENSITE STRUCTURES

The influence of P on impact toughness test and SEM observation was investigated on the 30CrMnSiA steel with pearlite, bainite and martensite-bainite mixed structures. Results showed that the cleavage element on the fracture surface increases and the impact toughness decreases as the increasing of P content. The intergranular fracture appeared till P up to 0.020%. An impact toughness sequence of various structures in the steel influenced by P may be arranged as: martensite+bainite>bainite>pearlite.