Abstract: Method of welding edges which are placed against each other of at least one workpiece of metal by means of a laser is indicated, in which the areas of the workplace located at the edges are subjected to a pretreatment for increasing the absorption capacity of the light of the laser. For this purpose, initially color is sprayed or splashed onto the areas of the workpiece located at the edges, while avoiding any mechanical contact of the workpiece, by means of a device (7) which emits the color, and the edges of the workpiece are subsequently welded together by means of a laser (11).

Abstract: A device for undulating a metal pipe having an undulation extending transversely of its longitudinal direction. The device has a ring-shaped undulating head drivable by a first electric motor and is rotatable about its axis in the operating position and a ring-shaped undulation disc, coupled to the ring-shaped undulating head, projects radially inwardly from the undulation head. The undulation disc is mounted in the undulation head so as to be adjustable in the radial direction. A support, coupled to the undulation head, is arranged so as to also be rotatable about the axis of the undulation head. An adjusting mechanism acting on the undulation disc is mounted on the undulation head. The adjusting mechanism serves for radially adjusting the undulation disc and is adjustable by the support. The support is connected to a second electric motor serving for rotating the support about the axis (A) of the undulation head.

Abstract: A device for continuously manufacturing pipes of metal, wherein the device includes a shaping unit (4) for shaping a pipe with a slot extending in the longitudinal direction from a longitudinally arriving metal strip, a welding device (7) for welding the contacting edges of the metal strip at the slot of the pipe, and a pulling device for pulling the pipe (9) which is now circumferentially closed in its longitudinal direction. The welding device (7) is composed of at least two separate welding heads (12,13) arranged in the pulling direction of the pipe (9) at a distance from each other, wherein the welding heads (12,13) each have at least one non-burning electrode.