| 摘要 |
PURPOSE:To obtain a steel having superior tensile strength, yield ratio and workability by rolling and coiling a steel slab consisting of specified amounts of C, Si, Mn, Al and Fe under prescribed conditions. CONSTITUTION:A steel consisting of, by weight, <=0.6% C, <=0.5% Si, <=2% Mn, <=0.05% Al and the balance Fe and satisfying relation represented by formula 97.6(%C)+11(%Si)+14.5(%Mn)>=52.4 is manufactured by refining. A slab of the steel is heated, rough-rolled and finish-rolled at 800-1,000 deg.C and 30-80% total draft with a tandem rolling mill having 3-5 stands. It is then water-cooled and coiled at 550-650 deg.C. Thus, a hot rolled high tension steel for a resistance welded steel pipe having >=5.5kg.f/mm<2> tensile strength, <=62% yield ratio, <=8mm thickness and superior workability is obtd.
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