Method of detecting fault in piercing-rolling and method of producing seamless pipe or tube

摘要

The object is to provide a method of detecting a fault which ensures high-accuracy detection of a fault in piercing-rolling. A piercing-rolling mill (10) is provided with piercer rolls (1a, 1b), a piercer plug (3), a rolling load sensor (4), a thrust load sensor (5), and a control device (6). The control device (6) measures a rolling load parameter corresponding to the rolling load of the piercer rolls (1a, 1b) and a thrust load parameter corresponding to the thrust load of the piercer plug (3), and detects a fault in piercing-rolling on the basis of a measured value of the rolling load parameter and a measure value of the thrust load parameter.

主权项

1. A method of detecting a fault in piercing-rolling when a billet is piercing-rolled using piercer rolls and a piercer plug, the method comprising:
piercing-rolling the billet using the piercer rolls and the piercer plug; measuring a rolling load parameter corresponding to a rolling load of the piercer rolls and a thrust load parameter corresponding to a thrust load of the piercer plug during the piercing-rolling step; and detecting a fault in piercing-rolling on the basis of the rolling load parameter value and the thrust load parameter value measured in the measuring step, wherein: it is judged that a slippage fault in piercing-rolling has occurred in the case where the thrust load parameter value does not exceed a first threshold value of thrust, after the billet is gripped by the piercer rolls, by the time a first prescribed time elapses after the rolling load parameter value exceeds for the first time a first threshold value of rolling; and
it is judged that a head jam fault in piercing-rolling has occurred in the case where the rolling load parameter value does not exceed a second threshold value of rolling, after the billet is gripped by the piercer rolls, by the time a second prescribed time elapses after the thrust load parameter value exceeds for the first time a second threshold value of thrust.