| 摘要 |
PURPOSE:To manufacture a low alloy steel with superior sulfide stress corrosion cracking resistance by hardening a low alloy steel contg. a specified percentage of C, Si, Mn, Al, P, etc. followed by tempering under specified conditions. CONSTITUTION:A low alloy steel contg., by wt., 0.05-0.35% C, 0.01-0.03% Si, 0.15-1.5% Mn and 0.005-0.1% Al as principal components and further contg. <=0.1% Mo and 0.03-0.15% V is prepared. The P, Si and La contents of the steel are adjusted so as to satisfy equation (Si+0.05)[P-1/4.5La]<=0.00375 in case of >=700 deg.C tempering temp. and equation (Si+0.05)[P-1/4.5La]<=0.00075 in case of 650-<700 deg.C tempering temp. The alloy is hardened and tempered at 650 deg.C- the Ac1 point in a short time such as <=300sec. |
