| 摘要 |
PURPOSE:To improve the quality of an expanded pipe by a simple mechanism and to prevent the spattering and overconsumption of a lubricant, by spraying the lubricant on a rolling part from a plug during plug-mill rolling, and blowing a high-pressure gas from the front end of a plug bar to the return direction during return stroke. CONSTITUTION:In plug mill rolling, a lubricant 14 is supplied 20 to the flow passage 19 of high-pressure gas 15 to supply the lubricant 14 from nozzles 39 to a rolling part through supplying pipe lines 17, 38 in order to lubricate the rolling part. In return stroke, a plug 3, 4, 35 is separated from a taper contact-surface 34, and the spraying is stopped by a spool 45 advanced by a spring 50, and only the high-pressure gas 15 is sent to a front-tip fittings 6 of plug by changing valves 20, 30 by the signal control 32 of a load cell 31 of roll 5b. Accordingly, the high pressure gas 15 is blown to the return direction from the flow passage and a nozzle 43, to descale and clean the inner surface of an expanded pipe 4, thereby improving the quality of the inner surface of pipe 4 and preventing the spattering and overconsumption of lubricant 14. |
