Abstract: The invention concerns a welding device and a welding method, in particular of tubular parts (c1, c2) such as abutting metal conduits to form pipeline metal pipes, which consists in effecting the penetrating pass from outside. The invention is characterized in that it consists in creating a single liquid weld metal under the simultaneous action of at least one laser beam (1) transmitted by optical fiber and at least one electric arc protected by gas generated from a consumable electrode (2a) constituting the filler material. The invention is mainly applicable to the construction of pipelines.

Abstract: The invention concerns a method for machining the ends of a metal conduit (1) for forming, when it is abutted with identical conduits, a pipeline pipe, to form at the plane of the parting line (3) with another identical conduit a V-shaped bevel. The invention is characterized in that it consists in cutting the ends of the conduit so that the profile of each end has at least one first cross-section, at the inner edge, designed to constitute part of the root face of the V-shaped bevel and an arc-shaped section linking said cross-section of the profile to a rectilinear section (5) inclined relative to the cross-section of said profile, at the outer edge of the tubular part. The invention is applicable to metal conduits, in particular for pipelines.