| 摘要 |
Mfr. of high performance tubes having improved stress corrosion resistance comprises froming a tube from a killed steel contg. (by wt.) 0.20-0.35 % C, 0.35-0.90 % Mn, 0.80-1.50 % Cr, 0.15-0.75 % Mo, max. 0.25% Ni, max. 0.35% Cu, max. 0.04% P, max. 0.04% S, max. 0.35% Si, balance Fe and trace impurities. The tube, having a cross- sectional area 10-40 % greater than the desired value, is given a first intercritical heat treatment to recrystallising and refining the grain structure. Surface defects are then removed by grinding, followed by sizing and cold working to the final demensions. Th tube is given a second intercritical heat treatment and is then quenched and tempered to produce a tempered martensite structure.
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