| 摘要 |
<p>PROBLEM TO BE SOLVED: To extend plug life by using a temp. control means, arithmetic means, controller, etc., in the piercing rolling method of hot seamless metal tube so as to suppress erosion of the tip part and side face part of a plug. SOLUTION: An arithmetic means 8, in which a temp. of each part of a plug 3 is inputted from plural temp. measuring means 7a in piercing/rolling, when measured temp. is below the plug eroding temp. set beforehand, without changing plug cooling condition and piercer's piercing rolling condition, transmits the signal for next rolling to a plug cooling device 10 and piercer controller 9. Further, when the measured temp. is the plug eroding temp. set beforehand or more, the signal under condition properly changing plug cooling condition and piercer's piercing rolling condition is transmitted to a plug cooling device 10 and piercer controller 9. Further, when the temp. resulting from change of plug cooling condition and piercer's piercing rolling condition is not below the plug eroding temp. set beforehand, the signal of interruption of plug use is outputted to the plug cooling device.</p> |
