Make doing with the production mannered

摘要

PROBLEM TO BE SOLVED: To produce a steel for resistance welded tube, minimal in the occurrence of defects in a resistance weld zone and improved in crack resistance and toughness, by limiting the amount of oxygen in a molten steel refined in a converter to a specific value or below, adding a Ti alloy containing specific amounts of Ti, and continuously casting the steel of specific composition. ;SOLUTION: Vacuum degassing and/or deoxidation with Mn or Si is applied to a molten steel refined in a converter and tapped, by which the amount of oxygen in the moltern steel is regulated to ≤250 ppm. Subsequently, an alloy, having a chemicaln composition consisting of, by weight, 10-70% Ti and the balance one or ≥2 elements among Fe, Mn, and Si with inevitable impurities, is added to the above molten steel. The steel, which has a composition containing, by weight, 0.010-0.2% Ti, 0.01-0.35% C, 0.02-0.5% Si, and 0.1-2.0% Mn and also containing Al, P, and S limited to ≤0.006%, ≤0.015%, and ≤0.008%, respectively, and having the balance iron with inevitable impurities, is cast continuously. By this method, the steel for resistance welded tube, excellent in resistance to sour, can be obtained.;COPYRIGHT: (C)1998,JPO