| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that, in a conventional technology, any technology of detecting very small weld defect of the size of around 50μm in a vicinity of a surface of a tubular body which is generated in a weld part of an electric resistance welded steel tube has not been established yet, and a status in which the electric resistance welded steel tube having such very small weld defect is mixed in products can be hardly prevented. SOLUTION: In a method for manufacturing an electric resistance welded steel tube for continuously welding edges of a V-shaped gap formed by forming a strip in a tubular shape, the brightness of a weld part after the welding and before the bead cutting is monitored by a brightness sensor 10, and thereafter, the weld part is inspected by an ultrasonic flaw detector 11 using an array probe on the downstream side of the bead cut. COPYRIGHT: (C)2011,JPO&INPIT |
