| 摘要 |
PURPOSE:To manufacture titled rail serviceable for high speed transportation causing little vibration and noise, by hot rolling the low expansion high Mn steel, comprising specified amount of C, Si, Mn and P, and specified amount of either one or more of Cr, Mo, Ti or Ca, and the balance of Fe, into rail under the limited conditions of temperature and forging ratio, and by welding these rails. CONSTITUTION:The low expansion high Mn steel, comprising C<1.5%, Si<3%, 10-40% Mn and P<0.05%, either one or more of Cr<15%, Mo<8%, Ti<5% or Ca<0.05%, and the balance of Fe, is hot rolled into a rail at 700- 1,250 deg.C by 3 or higher forging ratio; then, these rails are welded into a long sized rail. According to this method, the weld cracks are not generated, and the welding becomes possible without causing cracks under the condition of such large heat-input as 60,000 joule/cm (in case of the conventional method, the weld cracks are generated by the heat-input more than 7,000 joule/cm). |
