| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for accurately, promptly and simply evaluating hydrogen cracking resistivity in steel products of relatively-lower tensile strength as ≤800 MPa. Ž<P>SOLUTION: This is the method for evaluating hydrogen cracking resistivity in any steel product with its tensile strength (TS) of ≤800 MPa. In the method, target additional amplitude stress of σ (MPa) ±1-30% which meets formulae: (1) σ=YS×α, and (2) σ<TS at strain rate of 10<SP>-6</SP>-10<SP>-2</SP>/min is added to the above steel product while charging hydrogen to the steel product or taking hydrogen-escape preventive measures for the steel product after the hydrogen charging of it, evaluating hydrogen cracking resistivity of the steel product based on the time until crack arises on the steel product [For the above formulae (1) and (2), σ:target additional stress (MPa); YS:yield strength (MPa); TS:tensile strength (MPa); and α:coefficient (0.5≤α<1.2)]. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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