Temperature Pattern Measurement and Weld Control in Electric Resistance Welded Tube Mill

Abstract

In order to realize highly reliable quality of electric resistance welded (ERW) tubes, it is indispensable to grasp precise heat condition of weld portion. Out of such need, the pattern thermometer (PT) have been developed as a sensor which can directly measure temperature pattern of weld portion, and it can also pick out the temperature of the position which is necessary for weld control in its measuring view.
Following results have been obtained by installing the PT in the ERW tube mill.
(1) The temperature of the portion just before weld V point is suitable for the index to control heat input for weld, because it can be measured stably and well corresponds to heat condition of weld portion.
(2) The highly stabilized weld control system have been achieved by combining feed-back control of weld temperature measured by the PT with feed-forward control for compensation of wall thickness fluctuation.