| 摘要 |
PURPOSE:To prepare the titled Nb-containing high tensile hot rolled steel plate being suitable for deep drawing work, by heating of a slab containing C, Mn, Si, N, sol. Al, Nb and Cr before rough and finishing rolling at a fixed temperature and thereafter winding the rolled plate at a specific temperature. CONSTITUTION:Steel comprising 0.03-0.20% C, 0.30-2.0% Mn, 0.05-1.0% Si, 0.0005-0.01% N, 0.005-0.10% sol. Al, 0.01-0.10% Nb, 0.1-1.5% Cr and substantially the remainder of Fe is ingotted by an ordinary process. Subsequently, the thus composed steel is transformed into a slab by rolling or continuous casting, and then the slab, after heating at 1,200-1,320 deg.C, is roughly and finishingly rolled to prepare a thin steel plate preferably 6mm. or less thick. The essential condition of the process is to finish the finishing rolling at 800-950 deg.C and then to wind the rolled sheet at 500-680 deg.C. As a result, the rolling conditions do not require particularly severe regulations and the titled steel plate can be easily obtained. |
