METHOD AND DEVICE FOR LONGITUDINAL SEAM WELDING OF PROFILED TUBES ON A TUBE WELDING SYSTEM

The invention relates to a method and a device for longitudinal seam welding of profiled tubes on a tube welding system which is connected to a system computer for process control, and to which a slotted tube (5) formed directly in line from a metal strip in a roll forming mill, or a slotted tube shaped from at least one sheet metal panel is supplied, in particular, for welding the longitudinal seam or the longitudinal seams, wherein the tube welding machine is equipped with a means (12) for measuring the temperature of the welding point which is effective at the narrowest location and is occupied by the metal edges of the slotted tube pressed together by means of rollers (8) to form a gap with a tapering V shape. The longitudinal seam welding can be optimised in that temperature fluctuations and shifting of the welding point can be detected by a thermal imaging camera (12) directed onto the vertex of the convergent V-shaped gap with the longitudinal seam being formed, wherein the continuously measured data are processed in the system computer (7) for regulating the welding process in such a way that the welding point (11) at the hottest degree of effectiveness thereof is always located at the same position.