JPS5480226A - Steel with superior hydrogen-induced cracking resistance - Google Patents

Abstract

PURPOSE: To give superior hydrogen-induced cracking resistance to steel by adding a specific amt. of Co and Cr to the steel and controlling the contents of Mo and W as impurities to each certain allowable amt.

CONSTITUTION: A steel is provided which contains C<0.25%, si<0.60%, Mn; 0.40W1.20%, Cu; 0.20W0.50%, Co; 0.60W5.0% and Al<0.10% while controlling the contents of impurities to P<0.025%, S<0.01%, Mo<0.05% and W<0.05%. Ni<0.40% may be added to the steel, and one or more out of Nb<0.08%, V< 0.10%, Zr<0.10%, Cr<0.50%, Ti<0.08% and B; 0.001W0.004% may further be added. Furthermore, the steel may contain one or more out of Ca<0.008%, Y<0.01% and lanthanides such as La, Ce and Sm<0.01%. The hydrogen-induced craking resistance of the steel is enhanced by the composite effect of Co and Cu, the addn. of other elements, and the control of components such as Mo and W which tend to accelerate penetration of hydrogen into steel.

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