| 摘要 |
<p>PURPOSE:To produce a hot rolled steel plate for steel tube having high strength and high toughness and excellent in sour resistance by subjecting a continuously cast stock having a specific composition containing C, Mn, P, S, and Fe as essential components to respectively specified hot rolling, cooling, coiling, and tempering. CONSTITUTION:A continuously cast stock which has a composition containing, by weight, 0.04-0.20% C, 0.6-2.0; Mn, <=0.020% P, and <=0.004% S as essential components practically free from Ni, Cu, and Ca, further containing one or more kinds among <=0.06% Nb, <=0.07% V, <=0.03% Ti, <=0.50% Mo, and <=0.50% Cr, and having the balance Fe with inevitable impurities is subjected to the completion of hot rolling at >=720 deg.C. The resulting hot rolled plate is cooled on a hot run table at (5 to 20) deg.C/sec average cooling rate and coiled at 450-570 deg.C. Then, this steel plate is tempered at 500-700 deg.C. By this method, the hot rolled steel plate excellent in hydrogen induced blister resistance and hydrogen induced cracking resistance and having about (50 to 75)kgf/mm<2> tensile strength can easily surely and economically be obtained.</p> |
