| 摘要 |
PURPOSE:To improve the formability and coating baking hardenability of a steel plate manufactured through hot rolling, cold rolling and annealing processed and to well enhance the steength thereof by subjecting the plate to specified treatment composed of introduction of a strain, aging and other treatment. CONSTITUTION:A steel slab is hot rolled, cold rolled to a predetermined thickness, and annealed. A light strain is introduced into the resulting plate so that it is uniformly distributed all over the plate. The plate is then aged in the temp. range of 45-150 deg.C to finely precipitate [C] and [N] dissolved in the steel, and it is skin- pass-rolled to provide baking hardenability as well as to effectively prevent natural aging. The strain is introduced to induce strain aging, so the method of introducing the strain is not restricted so far as a strain enough for strain aging is produced. Accordingly, after introducing a strain enough for strain aging at 45-150 deg.C the plate may be cooled slowly to ordinary temp. and skin-pass-rolled. |
