EFFECT OF TEXTURE ON HYDROGEN EMBRITTLEMENT SUSCEPTIBILITY OF STEEL

The effect of texture on the hydrogen embrittlement directivity of cold-rolled sheets of EB26-1 high purity ferrite stainless steel and 300M super high strength steel was studied. The embrittlement was evaluated by the impact tests. The directional properties of texture in specimens were examined by inverse-pole-figure method. And the morphology of surface and fracture of impact specimens was observed by SEM. It was found that the hydrogen embrittlement of cold-rolled sheet is markedly directional. The susceptibility in charged parallel to the rolled direction of sheet is the highest, while in perpendicular, is the lowest. The directivity of hydrogen embrittlement may be satisfactorily interpreted by the model of dislocation short-circuiting-diffusion paths of hydrogen. Let the texture parameter, P]_E=P_(110) +P_(211)+1/2(P_(110)+P_(321)), denote the distributive probability of dislocation lines normal to the surface. P]_E seems to be closely related to the susceptibility of hydrogen embrittlement under condition of equal dislocation density. It has been confirmed by the experimental results of 300M steel sheet. Thus, the value P]_E is one of the controlling factrs for hydrogen embrittlement.