METHOD FOR CO2 / LASER WELDING WITH A DYNAMIC JET NOZZLE

摘要

The laser welding process comprises generating a laser beam using a carbon dioxide laser generator, supplying a nozzle (4) with a gas or gaseous mixture, distributing a jet of protection gas along a direction of a plane of joint using the nozzle, operating, using the laser beam, fusion and vaporization of a metal consisting of the metallic parts to form a capillary of metal vapor (2) with concomitant formation of a metal plasma at the thickness of the pieces or at a level of joint. The metal plasma propagates outside the capillary of metal vapor to form a cluster (1) of metal plasma. The laser welding process comprises generating a laser beam using a carbon dioxide laser generator, supplying a nozzle (4) with a gas or gaseous mixture, distributing a jet of protection gas along a direction of a plane of joint using the nozzle, operating, using the laser beam, fusion and vaporization of a metal consisting of the metallic parts to form a capillary of metal vapor (2) with concomitant formation of a metal plasma at the thickness of the pieces or at a level of joint. The metal plasma propagates outside the capillary of metal vapor to form a cluster (1) of metal plasma above the plane of joint. The jet of protection gas is oriented towards the direction of metal plasma cluster so as to make them form above the plane of joint. The jet of protection gas impacts the top of the metal plasma cluster and single metal part that is not melted by the laser beam. The fusion and vaporization are operated progressively by relative displacement of the beam according to the parts to be welded along the plane of joint. The distance between an axis of gas jet and the laser beam axis measured between the points of impact of the gas jet and the laser beam on an upper surface (7a) of the pieces is higher than or equal to 1.5 times the internal diameter of the nozzle. Internal diameter of the nozzle relative to the upper surface of the pieces is 1-50 mm. The nozzle is positioned according to the plane of joint, such that angle of inclination (alpha ) of the axis of weld cordon and projection of the axis of the nozzle in the plane of head to be welded is 170[deg] to -170[deg] . The nozzle is positioned according to the upper surface of the parts to be welded, such that angle (theta ) of axis (5) of gas jet or the nozzle is 5-70[deg] . The gas jet is distributed at a speed of 250 m/s.