For both cast and forged steels, the fracture modes are clearly dependent upon K_1 at the crack tip and a transition from dimple to quasi-cleavage or intergranular is observed on the fracture surfaces with decreasing K_1.

• 这与断口观察一致,由此可以解释K_(ISCC)的差异。 尽管断口形貌明显依赖开裂时的K_I值,但在K_(ISCC)附近锻钢全是沿品断口,而铸钢则以准解理为主。