Abstract: A device for overlay-welding a pipe interior having an arm extensible into the interior of a respective pipe, the arm carrying a welding head at a free end thereof includes a rotating device in the form of a wheel surrounding and supporting the pipe, and a swiveling device disposed in the wheel for moving the pipe in a circular arc about the center of the wheel and transversely to the plane of the wheel, the arm being curved and being secured to a part of the swiveling device connected to the wheel, the welding head being rotatable in the plane of the wheel for overlay-welding pipes formed at least partly with a bend therein.