| 摘要 |
PURPOSE:To manufacture a steel material with superior hydrogen induced cracking resistance by reducing segregation in a steel material by diffusion in a hot rolling stage. CONSTITUTION:When a billet is hot rolled, it is heated to 1,000-1,350 deg.C and rolled at >=5% draft. The upper limit of the draft is 50%. The hot rolled material is reheated to 1,000-1,350 deg.C, held at the temp. for >=10hr, and subjected to finish rolling. C, Mn, P, S, etc. segregated densely at the central part are diffused to the peripheral part to eliminate the dense segregation. |
