| 摘要 |
PROBLEM TO BE SOLVED: To obtain an earthquake resistant steel pipe free from the generation of local buckling caused by compression and bending stress exerted in the direction of a pipe axis and free from the generation of cracking and rupture caused by the local buckling by regulating the characteristic value of the compsn. of a steel pipe to a specified range. SOLUTION: As a steel pipe for gas pipeline, water piping or the like, it has a compsn. contg., by weight, <=0.15% C, <=0.5% Si, <=2.0% Mn, <=0.03% P and <=0.01% S or furthermore contg. one or >= two kinds among <=0.5% Cu, <=0.5% Ni, <=0.5% Cr, <=0.5% Mo, <=0.08% Nb, <=0.1% V, <=0.08% Ti, <=0.1% Zr, <=0.004% B, <=0.5% Co, <=0.5% W, <=0.005% Ca and <=0.02% rare earth metals, in which PCM expressed by C%+Si%/30+Mn%/20+Cu%/20+Ni%/60+Cr%/20+Mo%/15+V%/10+5×B% is also regulated to 0.1 to 0.25%, and EFC value expressed by C%-(12/93)×Nb%-(12/51)×V%-(12/48)×Ti%-(12/91)×Zr% is regulated to <=0.1%.
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