| 摘要 |
PURPOSE:To control exactly weld heat input and to obtain stably a product having good quality by measuring the discharge rate of the molten steel to be melted and discharged in front of a weld point in the stage of welding an electric welded steel pipe and controlling the electric power to be thrown in such a way that said discharge rate coincides with a target value. CONSTITUTION:The discharge rate S of the molten steel 3 to be melted and discharged is measured by an image processing unit 6 and an arithmetic unit 7 from the image of the periphery of a weld point P photographed by a camera 5 installed above the weld point P and the electric power to be thrown to a welding machine 4 is controlled by a PID controller 8 in such a way that said rate attains equal to the target value in a production line for the electric welded steel pipe in which a strip is formed to a round shape, high frequency current is supplied from the machine 4 to a feed point 2 to melt the edges and the edges are welded at the weld point P. The position of the weld point P and V-convergence angle theta are more preferably determined from the above-mentioned image preferably in parallel with the above-mentioned control are further a plate thickness (t), line speed (v), the voltage Ep, current Ip, etc. of the machine 4 are inputted to the unit 7 which compares the calculated discharge rate of the molten steel and the target value and executes the control until the measured value of the succeeding discharge rate is determined. |
