| 摘要 |
PURPOSE:To obtain seamless steel pipe without causing hydrogen induced cracking under NACE liquid atmosphere without adding Ca, by suppressing S in steel to extremely low value and forming pipe, then reheating and applying heat treatments of quenching and tempering. CONSTITUTION:Steel contg. 0.05-0.15% C, 0.01-0.50% Si, 0.5-1.5% Mn, <=0.015% P, 0.01-0.08% Al, S restricted to <=0.0015% and the balance Fe is formed to pipe. Thereafter, the steel pipe is reheated immediately or after cooling, quenched from >Ac3 point of the material - <=1,000 deg.C temp., next, tempered to temp. of >=580 deg.C- <Ac1 point of the material. In this way, the titled pipe under NACE liquid (H2S is saturated with 5% NaCl + 0.5% CH3 COOH) atmosphere is obtd. without adding Ca.
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