| 摘要 |
PURPOSE:To easily and inexpensively obtain a PC steel bar and steel wire having excellent roughness, etc., by subjecting a steel contg. a specific ratio each of C, Si and Mn to hot rolling under adequate conditions and to coiling and water quenching then to adequate cold working. CONSTITUTION:The steel contg. 0.05-0.50wt% C, 0.10-2.5% Si and 0.5-2.5% Mn are hot rolled. The wire under rolling is forcibly cooled to maintain the wire temp. in a roughing mill train, intermediate mill train and finishing mill train at <=1,000 deg.C. The temp. on the inlet side of the finishing mill train is maintained at 800-900 deg.C and the finish rolling temp. at <=960 deg.C. The wire after the rolling is precooled down to 750-850 deg.C and is water-quenched right after coiling to an annular shape. The wire is then subjected to cold working at <10% and >=4% reduction of area and thereafter the wire is subjected to leveling and to bluing preferably in a 200-450 deg.C range. The PC steel bar and steel wire having the excellent toughness with a decreased relaxation loss are thereby obtd.
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