| 摘要 |
PURPOSE:To improve the resistance to sulfide stress corrosion cracking by hardening and tempering a steel contg. prescribed percentages of C, Si, Al, Nb, Zr, Ti, P, S, Mn, Cr and Mo under prescribed conditions. CONSTITUTION:A steel contg., by weight, 0.15-0.5% C, 0.1-0.3% Si, 0.005-0.1% Al, 0.01-0.1% Nb, 0.005-0.1% in total of Zr and/or Ti, <=0.005% P, <=0.005% S, 0.12t<1/2>-0.25t<1/2>% Mn [t is the thickness (mm.) of a steel pipe as a product] and 0.4t<1/2>-0.8t<1/2>% Cr [Cr(%)/Mo(%)=1.5-2.5] is hot worked into a seamless steel pipe, and the inside and outside of the pipe are simultaneously hardened. The pipe is then tempered at 650 deg.C- the Ac1 point. |
