| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for producing a hot rolled steel sheet for working in which elongation exceeding 50% can be realized by a common low carbon steel without adding special alloy elements and free from the generation of buckling and stretcher strains. SOLUTION: A slab contg., by weight, 0.01 to 0.08% C, 0.05 to 0.5% Mn, 0.003 to 0.5% Si, <=0.05% P, <=0.02% S, 0.005 to 0.3% Al, <=0.007% N, 0.0005% to 0.005% B, and the balance Fe with inevitable impurities is subjected to low temp. heating at <=1,150 deg.C and is subjected to rough rolling to form into a sheet bar, which is thereafter coiled at the Ar3 transformation point or above, is held for >=3sec at a cooling rate of <=1 deg.C/s and is thereafter recoiled. Then, the head of the sheet bar is joined to the tail of the sheet bar subjected to the rough rolling beforehand and preceding on the rolling line, which is continuously subjected to hot rolling at a finishing temp. of the Ar3 transformation point or above and is coiled at a coiling temp. of >=600 deg.C.</p> |
