UNANNEALED WELDED STEEL TUBE FOR WORKING, OBTAINED BY FORMING HEAT RESISTANT FERRITIC STAINLESS STEEL SHEET INTO TUBE BY WELDING

摘要

PROBLEM TO BE SOLVED: To provide a ferritic stainless steel tube, excellent in heat resistance and toughness at low temperature and applicable to an automobile exhaust gas passage member, in an as-unannealed state after tube making by welding. ;SOLUTION: The steel tube is constituted of an unannealed welded steel tube for working, obtained by applying tube making by welding to a heat resistant ferritic stainless steel sheet which has a composition consisting of, by mass, ≤0.02% C, 0.7-1.0% Si, 1.0-1.5% Mn, 13.5 15.5% Cr, ≤0.02% N, 0.30-0.60% Nb, 0.02-0.24% Cu, 0-0.03% (including 0%) Al, and the balance Fe with inevitable impurities and satisfying, within the above ranges of contents, 1.45≥Nb+Si and 1.35≤Nb+1.2Si.;COPYRIGHT: (C)1999,JPO