Influence of Externally Imposed Constraint on the Hydrogen Embrittlement of Steels

摘要

This paper describes the results of an experimental program on the hydrogen damage of high and low strength steels using different test techniques that varied the stress state and the constraint imposed on the material. The influences of gaseous and electrolytic hydrogen on the embrittlement characteristics of high-strength 4340, A106B, and AlSl 1015 steels were studied via a series of tensile, delayed failure, disk rupture, and fracture mechanics tests. Results indicate that externally imposed constraint plays a vital role in the hydrogen damage of high-strength steels. However, in the case of low-strength steels, externally imposed constraint was found to be unimportant for hydrogen-induced cracking. Also, it was found that fracture modes were characteristic of the constraint dependence of the material with regard to hydrogen-induced cracking. The pros and cons of the constraint agreement and its relevancy to material and experimental variables in determining the material's susceptibility to hydrogen damage are discussed. 17 figures, 7 tables. (ERA citation 08:007901)