Abstract: The invention relates to a laser cutting method for cutting a stainless steel workpiece using laser beam generation means comprising a silica fiber with an ytterbium-doped core to generate the laser beam. Preferably, the laser beam generated by the ytterbium-based fiber has a wavelength between 1.07 and 1.09 ?m, a quality factor of the laser beam is between 0.33 and 8 mm·mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from O2, CO2, H2 and CH4.

Abstract: Process for laser welding at least one metal workpiece (1) by a laser beam (3), the workpiece having a surface coating (2) containing aluminum, characterized in that the laser beam (3) is combined with at least one electric arc (4) so as to melt the metal and actually weld the workpiece(s).

Abstract: The invention relates to a hybrid laser/arc-welding method using an electric arc and a laser beam that are combined together within a single welding melt to which molten metal is supplied by melting a filler wire, wherein the welding melt is provided on at least one steel part including an aluminum surface coating, and a protective gas is used, characterized in that the filler wire contains at least 3 wt % of one or more gammagenic elements, in particular the gammagenic elements selected from C, Mn, Ni and N, and the protective gas consists of helium and/or argon with the addition of at least 10 vol % of nitrogen or oxygen. The method of the invention is particularly suitable for welding end-welded flanks used in the field of manufacturing automobiles or for tube welding.

Abstract: The invention relates to a laser cutting method for cutting a stainless steel workpiece using laser beam generation means comprising a silica fibre with an ytterbium-doped core to generate the laser beam. Preferably, the laser beam generated by the ytterbium-based fibre has a wavelength between 1.07 and 1.09 ?m, a quality factor of the laser beam is between 0.33 and 8 mm·mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from O2, CO2, H2 and CH4.

Abstract: The invention relates to a laser cutting method for cutting a C—Mn steel workpiece, characterized in that laser beam generation means comprising at least one silica fiber with an ytterbium-doped core is used to generate the laser beam. Preferably, the ytterbium-based fiber has a wavelength between 1.07 and 1.1 ?m, preferably 1.07 ?m, the quality factor of the laser beam is between 0.33 and 8 mm.mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon, oxygen, CO2 and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from H2 and CH4.

Abstract: The invention relates to a hybrid laser/arc-welding method using an electric arc and a laser beam that are combined together within a single welding bath, to which molten metal is supplied by melting a filler wire, wherein the welding bath is provided on at least one steel part including an aluminum surface coating, and a protective gas is used, characterized in that the protective gas consists of at least one main compound selected from argon and helium, and of at least one additional compound selected from nitrogen and oxygen.

Abstract: The invention relates to a hybrid laser/arc-welding method using an electric arc and a laser beam that are combined together within a single welding melt to which molten metal is supplied by melting a filler wire, wherein the welding melt is provided on at least one steel part including an aluminum surface coating, and a protective gas is used, characterized in that the filler wire contains at least 3 wt % of one or more gammagenic elements, in particular the gammagenic elements selected from C, Mn, Ni and N, and the protective gas consists of helium and/or argon with the addition of at least 10 vol % of nitrogen or oxygen. The method of the invention is particularly suitable for welding end-welded flanks used in the field of manufacturing automobiles or for tube welding.

Abstract: The invention relates to method for cutting a part using a laser beam, involving the use of laser beam generation means comprising at least one ytterbium-based fibre having a wavelength of between 1 and 4 ?m in order to generate the laser beam. The laser beam is selected to have a power of less than 100 kW, a power density of at least 1 MW/cm2, a focused beam diameter of at least 0.1 mm and a quality factor (BPP) of less than 10 mm·mrad.

Abstract: The invention relates to a particular optical configuration employed in a solid-state laser, in particular a fiber laser, cutting head for controlling the problems of focal drift and laser damage of the optics of the focusing head and to a laser unit equipped with such a focusing head, in particular an ytterbium-doped fiber laser unit.

Abstract: The invention relates to a laser cutting method for cutting a C—Mn steel workpiece, characterized in that laser beam generation means comprising at least one silica fiber with an ytterbium-doped core is used to generate the laser beam. Preferably, the ytterbium-based fiber has a wavelength between 1.07 and 1.1 ?m, preferably 1.07 ?m, the quality factor of the laser beam is between 0.33 and 8 mm.mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon, oxygen, CO2 and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from H2 and CH4.

Abstract: A method of cutting a work-piece to be cut by a laser beam, in which an incident laser beam is generated that has an initial beam parameter product (BPP), given by means of a laser source, preferably an ytterbium-doped or erbium-doped fiber laser source, coupled to at least one optical fiber for conveying the beam. Said incident laser beam is brought to a focusing head comprising at least one optical focusing device. The incident laser beam is focused by means of said optical focusing device, so as to obtain a focused laser beam, and the work-piece is cut by means of the focused laser beam. According to the invention, the quality factor of the incident laser beam is adjusted or modified by means of an optical device designed to be able to modify or vary the BPP of a laser beam so as to obtain a modified focused laser beam having a modified BPP which is different from the BPP of said incident laser beam. Associated equipment for implementing said method.

Abstract: Process for laser welding at least one metal workpiece (1) by a laser beam (3), the workpiece having a surface coating (2) containing aluminum, characterized in that the laser beam (3) is combined with at least one electric arc (4) so as to melt the metal and actually weld the workpiece(s).

Abstract: The invention relates to method for cutting a part using a laser beam, involving the use of laser beam generation means comprising at least one ytterbium-based fibre having a wavelength of between 1 and 4 ?m in order to generate the laser beam. The laser beam is selected to have a power of less than 100 kW, a power density of at least 1 MW/cm2, a focused beam diameter of at least 0.1 mm and a quality factor (BPP) of less than 10 mm·mrad.

Abstract: The invention relates to a method for welding at least one, preferably two metal parts to each other, by a laser beam consisting in using a laser beam (10), a first gas flow and a welding nozzle provided with an output orifice which is passed through by the laser beam and the first gas flow and in welding the part(s) by melting the metal thereof at a point of the laser beam impact with said weldable part(s) in such a way that a capillary (11) or a key hole (12) filled with metal vapour is formed. During welding, the first gas flow is directed only to the aperture of the metal vapour capillary in a direction perpendicular to the weldable part(s) in such a way that a dynamic gas pressure is produced.

Abstract: A method and an apparatus for welding with a laser beam. A shielding gas mixture of nitrogen and helium is used and the proportions of the component gases are modified depending on the laser beam's power or power density. Plasma formation in the shield gas is minimized by increasing the proportion of helium as the laser beam's power or power density increases.

Abstract: The invention relates to a welding process using a laser beam (FL1, FL2) to weld at least one metal workpiece, preferably to weld two metal workpieces together, in which: a first laser beam (FL1) is employed and said first laser beam (FL1) is focused so that it strikes at least one workpiece to be welded and creates a keyhole-type capillary (KH) having a keyhole opening; a second laser beam (FL2) is used and said second laser beam (FL2) is focused in the keyhole (KH) opening created by said first laser beam (FL1); and the workpiece or workpieces are progressively welded by melting the metal of the workpiece or workpieces to be welded at the points of impact of the laser beams (FL1, FL2) with the workpiece or workpieces to be welded. The depth of penetration (x) of the first laser beam (FL1) is greater than the depth of penetration (y) of the second laser beam (FL2).

Abstract: The invention relates to a process for laser welding at least one metal workpiece (1) by a laser beam (3), said workpiece having a surface coating (2) containing aluminium, characterized in that the laser beam (3) is combined with at least one electric arc (4) so as to melt the metal and actually weld said workpiece(s).

Abstract: Methods for hybrid laser/MIG welding processes. A bevel formed between the edges of material to be welded together is partially filled with molten metal. The molten metal is delivered in the form of a filler wire, which is melted by a combined electric arc and laser beam. The welding speed is at least 2 m/min, the filler wire feed speed is at least 20 m/min and the filler wire diameter is less than 1.2 mm.

Abstract: The invention relates to a process for the braze-welding of steel workpieces using a laser beam, for example of the Nd:YAG, CO2, fibre or diode type, a consumable wire being the filler metal, and a gas mixture as gas shield, so as to produce a braze-welded joint between the workpieces. The consumable wire is based on copper and the gas mixture contains 40 to 60% oxygen and at least one gas chosen from argon, nitrogen and helium for the remainder.

Abstract: The invention relates to a laser cutting method for cutting a C-Mn steel workpiece, characterized in that laser beam generation means comprising at least one silica fiber with an ytterbium-doped core is used to generate the laser beam. Preferably, the ytterbium-based fiber has a wavelength between 1.07 and 1.1 ?m, preferably 1.07 ?m, the quality factor of the laser beam is between 0.33 and 8 mm.mrad, and the laser beam has a power of between 0.1 and 25 kW. The assistance gas for the laser beam is chosen from nitrogen, helium, argon, oxygen, CO2 and mixtures thereof, and, optionally, it further contains one or more additional compounds chosen from H2 and CH4.