| 摘要 |
PURPOSE:To economically produce a Cr-Mo steel having an excellent hydrogen erosion resistant characteristic by subjecting the Cr-Mo steel having a specific compsn. to hardening and annealing treatments then to tempering or stress relief annealing treatment under adequate conditions. CONSTITUTION:The Cr-Mo steel contg. <=0.20% C, <=0.60% Si, <=1.0% Mn, <=0.020% P, <=0.010% S, 2.0-3.5% Cr, and 0.8-1.6% Mo and the blance substan tially consisting of Fe is subjected to the hardening and annealing treatments. The above-mentioned steel is thereafter subjected to at least one pass of a tempering treatment and/or stress relief annealing treatment within a 600-750 deg.C range under such conditions under which the S value expressed by the formula attains >=810 [where, Ti and ti; temp. deg.C and time h of the 1st tempering treat ment or stress relief annealing treatment, h; number of the tempering treatment and/or stress relief annealing treatment (including n=1)]. The heat treatment of the Cr-Mo steel having the excellent hydrogen erosion resistant characteristic is thus executed. |
