| 摘要 |
PURPOSE:To manufacture cold rolled steel sheets excellent in deep drawing property by hot rolling low carbon and low manganese steel slabs and annealing them, after having hot rolled within the specific temperature range in the cooling process. CONSTITUTION:Steel slabs containing <0.10% C, <0.40% Mn, are made to steel sheets by ordinary hot rolling. In order to prevent the steel sheets from hardening and deteriorating in workability in the cooling process, the sheets are cooled at a cooling rate of 50 deg.C/sec or less from the temperature where the austenite phase disappers. Before being wound up, the sheets are annealed, after having been hot rolled at a reduction rate of more than 20% within a temperature range of 450- 150 deg.C. This enables to manufacture cold rolled steel sheets excellent in deep drawing property. |
