| 摘要 |
PURPOSE:To produce a steel wire rod having the quality equivalent to or better than that by a lead bath method at a low cost by conducting the middle and high carbon steel wire rod in an austenite state after hot rolling into cooling liquid produced therein wire a large number of bubbles by the gas blown therein, thereby subjecting the same to a patenting treatment. CONSTITUTION:A middle and high carbon steel wire rod 2 in an austenite state out from a finishing stand 1 of a hot rolling installation is introduced via guide rollers 3 successively into cooling vessels 4, 5, 6, 7. In the respective vessels 4, 5, 6, 7, a gas is blown through nozzles 9, 10, 11, 12 in the bottom part, whereby a large number of bubbles are produced in the cooling liquid in the inside. While the wire rod 2 passes through this cooling liquid it is cooled at prescribed cooling rates and are patented, after which it is taken up via pinch rollers 8. At this time, the amts. and sizes of the bubbles produced from the nozzles 9, 10, 11, 12 are disposed and controlled in conformity with cooling set temps. |
