| 摘要 |
PURPOSE:To obtain economically a hot-rolled steel sheet having excellent scale adhesion by hot rolling a hot steel billet obtd. by continuous casting of a specifically composed low alloy steel and coiling the hot-rolled sheet at a specific temp. then cooling the same in a non-oxidative atmosphere. CONSTITUTION:A steel consisting of 0.03-0.25% C, <=0.03% Si, 0.20-1.00% Mn, <=0.015% P, <=0.015% S, <=0.03% Cu, <=0.03% Cr, <=0.08 Al, <=0.1%, >=1 kind among Nb, Mo, V and Zr and the balance iron with inevitable impurities is melted. A steel billet obtd. by continuous casting of such steel is heated in a heating furnace or after cooling, the billet is reheated and is hot-rolled and thereafter the hot-rolled sheet is coiled at 550-750 deg.C. Such coil is cooled down to <=350 deg.C in a non-oxidative atmosphere consisting of N2, Ar or a gaseous mixture thereof. The hot-rolled steel sheet which is suitable for production of a pipe, drum, shape steel, etc. and has excellent scale adhesion is obtd. by the above-mentioned method.
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