PURPOSE: To automatically measure and also to correct the shape, that is, the bend, outside diameter and outer peripheral length of an electric resistance welded steel tube without arranging a bend straightening machine.
CONSTITUTION: In a line for manufacturing an electric resistance welded steel tube by continuously forming a band steel into a cylindrical shape and butt-welding both end parts, two outside diameter measuring devices 1 having distance sensors 3 on respective upper/lower and right/left sides of a rack 2 which is framed into a square are provided at a prescribed interval in the traveling direction of the electric resistance welded steel tube 7 on the upstream side of the cut-off device for the electric resistance welded steel tube. Operation processors 9 with which the bend of the electric resistance welded steel tube 7 is operated according to the measured values which are inputted from the distance sensors 3 on the respective upper/lower and right/left sides of two outside diameter measuring devices 1 and the outside diameter and outer peripheral length of the electric resistance welded steel tube 7 are operated according to the measured values which are inputted from the distance sensors 3 on the respective upper/lower and right/left sides of the outside diameter measuring device 1 of the preceding stage and the distances between respective sides that are preliminarily inputted are provided and the rolling reduction of sizer rolls 11 is controlled by outputting the operated results of the bend, outside diameter and outer peripheral length of the electric resistance welded steel tube 7 with the operation processor 9 to a sizer roll positioning device 12.
OTA TAKASHI
ICHIIRI KEISUKE
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