Effect of Hydrogen on Brittle-Ductile Transition of COR-TEN O and its Weld Material (1st Report, Brittle-Ductile Transition of COR-TEN O)

Storage tanks and pipelines of gaseous fuel are frequently installed in low temperature environ-ment. So, when gaseous fuel contains hydrogen, not only cryogenic embrittlement but also hydrogen embrittlement may occur in the equipments. In this report, the effect of hydrogen on brittle-ductile transition of COR-TEN O steel was studied by carrying out fracture experiments of hydrogen charged and non-charged materials over the temperature range from — 196°C to room temperature. The variations of fracture resistance expressed by CED with temperature for hydrogen charged and non-charged materials are compared. As the result, it is shown that the brittle-ductile transition temperature of hydrogen charged material is lower than that of non-charged one and, although the fracture resistance of charged material naturally becomes smaller in the upper shelf range, not the fracture resistance of non-charged material but that of charged one is a little bit larger in the brittle-ductile transition range.