| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing an electric resistance welded steel tube, by which the quality of a welded part is stabilized. SOLUTION: An SG rolls 4, which has a left and right bisected structure and can freely change a fin width, are provided before an SQ roll. When the outer diameter of a steel tube to be made is changed, a fin width D is changed so as to proportion to the outer diameter of the steel tube, so that the cross section shape of the tube is stabilized during welding operation without exchanging a roll. When thickness or strength changes, a V angle is positively changed by adjusting the fin width D, so that the quality of the welded part is stabilized by always welding the tube with an ideal V angle. COPYRIGHT: (C)2007,JPO&INPIT |
