METHOD FOR CONTROLLING WELDING INPUT OF LECTRIC WELDED TUBE

PURPOSE:To improve the reliability and quality of welded parts by measuring the thickness and pipe making speed of a strip-like material and the press contact force of squeeze rolls, and regulating the welding input according to the deviations from reference values. CONSTITUTION:The thickness measured value (t) which is the output of a plate thickness gage 20 is taken into a plate thickness delay device 24, and according to the pipe making speed V which is the output of a speedometer 22, the thickness measured value in the thickness gage position is delayed up to the welding position. An arithmetic setting device 30 calculates the rate of deviation with respect to the reference value of welding input according to the thickness measured value (t) and the pipe making speed V in the position corresponding to the welding position which is the output of a thickness delay device 24, and the press contact force P measured with a load gage 26 disposed to squeeze rolls and outputs the calculated optimum welding input E as a set value to a welding electric power source 16.