高強度鋼平滑材の遅れ破壊過程における擬へき開割れの役割
1992 年 58 巻 545 号 p. 78-83
詳細
1992 年 58 巻 545 号 p. 78-83
The mechanistic condition of delayed fracture was studied on the basis of fractographic analysis in the SEM photograph of the fractured surface of cathodically charged quenched/tempered SNCM439 and 0.36%C plain carbon steels. A typical feature of the fracture process of both materials can be characterized as the quasi-cleavage facet in the vicinity of the crack origin followed by the intergranular facet and dimple pattern resulting in a brittle fracture. The fracture condition of this brittle fracture can be characterized on the basis of two parameters, the nominal applied stress and the depth of the crack origin. Discussion has been made on the estimation of the threshold stress of the delayed fracture test from the application of the above brittle fracture condition.
