| 摘要 |
PURPOSE:To manufacture the cold-rolled steel strip having excellent quality surface for processing purpose at low cost by a method in which a short-time soaking and the subsequent aging treatment following a quick heating are carried out in a nonreductive atmospbere and then film adhered to the surface of a steel strip is removed in the continuous annealing of the cold-rolled steel strip. CONSTITUTION:The cold-rolled steel strip manufactured by a cold rolling following a hot rolling is continuously annealed in the processes involving a quick heating, a soaking treatment, the primary cooling, an aging treatment, and the secondary cooling. In this case, the time required for the said whole annealing cycle is made shortest and its operational efficiency is raised by using a jet type direct-heating furnace for the quick heating treatment and also a film for raising the heat radiation rate of the surface of steel strip is formed by using an inorganic oxide, a blackcolored organic substance, or an iron oxide. And, a soaking treatment and an aging treatment are darried out in a nonreductive atmosphere or an oxidative atmosphere and also the cooling time is shortened by using a vapor-water cooling method. Lastly, the film on the surface of the steel strip is removed, the time required for the annealing cycle is shortened, and the working efficiency of the annealing is raised. Thus, the manufacturing cost can be reduced. |
