| 摘要 |
PURPOSE:To heat a weld line part nearly correctly in normalizing an electrically welded pipe by plural induction heaters, by installing temp. pattern detectors in front of every heaters, and by controlling the positions of the heaters by control units. CONSTITUTION:An electrically welded pipe (l) is normalized heating its weld line by the induction heating coils 11a-11d of plural heaters 1a-1d while conveying said pipe (l) in the direction of the arrow. Detectors 2a-2d are arranged in front of every heaters 1a-1d in order to detect the position at peak temp. of said pipe (l). Detected signals are fed to control units 3a-3d so as to control the position of the heaters 1a-1d properly, hereby the change in relative position of weld line and the induction heating coils 11a-11d due to the twist of said pipe (l) caused by a thermal stress is corrected. Hence normalization is performed surely by heating the weld line of the said pipe (l) with plural induction heating coils nearly correctly. |
