EFFECT OF HYDROGEN CONTENT ON HYDROGEN EMBRITTLEMENT OF API X70 STEEL

摘要

The effect of hydrogen content on hydrogen embrittlement of high toughness API X70 line-pipe steels was studied. The hardness of conventional API X70 steel was measured before and after hydrogen charging. The various hydrogen contents for API X70 steel were charged at 10MPa gas pressure. The tensile test for hydrogen charged API steel was conducted at room temperature. The hardness increased slightly with hydrogen content. The fracture surfaces were changed from dimple type to quasi-cleavage type with hydrogen content. And external cracks were observed just only at 100% hydrogen content.