| 摘要 |
PURPOSE:To obtain a high toughness resistance welded tube having superior sour resistance by vanishing platy crushed Ca oxide type inclusions present in the butted part of a resistance welded tube and in the heat-affected zones on both sides of the butted part. CONSTITUTION:The composition of a resistance welded tube is composed of, by weight, 0.01-0.35% C, 0.02-0.5% Si, 0.1-1.8% Mn, 0.001-0.1% Al, <=0.001% Ca, <=0.02% P, <=0.0012% S [P(%)+25XS(%)<=0.04], one or more among 0.2-0.6% Cu, 0.1-1% Ni and 0.2-3% Cr, one or more among 0.1-1% Mo, 0.01-0.15% Nb, 0.01-0.15% V and 0.01-0.1% Ti and the balance Fe with inevitable impurities.
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