| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing various kinds of high strength steel bars by carrying out the controlled uniform cooling over the whole length of the steel bars just after hot rolling. SOLUTION: The steel bars are arranged in parallel with each other, and are moved so as to pass a cooling band while rotating about their axes and diagonally travelling. The cooling band is composed of an ordinary temperature fluidized bed. Covering plates are provided below passing loci, and the steel bars are brought into intermittent contact with the fluidized bed by appropriately opening and closing the covering plates, and similarly, heat reserving plates are provided above the passing loci, and a required cooling pattern can be obtained by selecting and combining air cooling and heat reserving by appropriately opening and closing the heat reserving plates. As a result, heat treatments, such as direct patenting, direct hardening, direct hardening and tempering, grain refining treatment, can be carried out to the steel bars. COPYRIGHT: (C)2009,JPO&INPIT
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