Installation for arc welding with several torches using a non-consumable electrode and double protective flux for welding tubes, each torch having the electrode tip located in the plane of the inner nozzle

摘要

An arc welding torch (1) comprises a tungsten electrode (2) with a pointed end (7), an internal tuyere (3) surrounding the electrode and an external tuyere (4) surrounding the internal tuyere. The annular edge (6) of the end of the internal tuyere and the point of the electrode are essentially situated in the same plane. The distance (d) separating a first plane (P) perpendicular to the longitudinal axis of the electrode and passing at the level of the surface of the annular edge and a second plane (P') passing through the pointed end of the electrode and that is parallel to the first plane is such that 0 = d = 1 mm, and the internal tuyere has an outlet orifice (9) with a diameter of between 5.3 and 7 mm. Independent claims are also included for : (a) an arc welding installation incorporating several of these welding torches; (b) a method of electric arc welding using one or more of these welding torches.