Abstract: An arc welding process using a consumable electrode, in which welding cycles follow one after another over the course of time, each comprising an arc period and a short-circuit period in which the liquid metal establishes a short-circuit between the end of the electrode and the workpiece or workpieces. Each cycle comprises the steps of: maintaining an arc current I2 at the same time as the consumable electrode is moved towards the workpiece; reducing the current so as to reach a minimum current I1 at the start of the short-circuit; reducing the speed of the consumable wire electrode; increasing the current over the short-circuit period in order to reach a maximum value I4; and then reducing the current over the short-circuit period in order to reach a minimum value I1.

Abstract: The invention relates to an arc welding method. According to the invention, a filler wire is subjected to a cyclical mechanical movement, whereby it approaches and, subsequently, moves away from the pieces to be welded in an alternating manner. In this way, a short circuit is created between the end of said filler wire and the pieces to be assembled and weld metal is deposited thereon, so that a weld joint is gradually produced between said pieces. The inventive method is characterised in that the pieces to be assembled are the constituent elements of a motor vehicle. For example, the elements to be assembled can be selected from the group comprising: the body shell, the rocker panel, tailored blanks, side members, wheel housings, under-seat crossmembers, foot reinforcements, dashboard crossmembers, front crossmembers, shock absorbers and the engine cradle. Preferably, the thickness of the elements to be welded is between 0.

Abstract: For MIG welding, either in a spray mode without current modulation or in a pulsed mode, of aluminum and aluminum alloys, with the use of a gas shield for at least part of the welding zone, the gas shield is a gas mixture consisting, by volume, of from 0.01% to 1.80% oxygen and from 15% to 98.2% helium, and any balance being argon.

Abstract: The process includes shielding of at least part of the welding zone with a gas mixture consisting of 1.2 to 1.70% oxygen and the balance being argon.

Abstract: The invention relates to a process for the MIG welding, in spray mode without current modulation or in pulsed mode, of aluminum and aluminum alloys, with the use of a gas shield for at least part of the welding zone. According to the process of the invention, the gas shield is a gas mixture consisting, by volume, of from 0.8% to 1.80% oxygen and from 15% to 99.99% helium, and possibly containing a balance of argon. Preferably, the gas mixture contains at least 1% oxygen.

Abstract: A process and a device for the gas-shielded MIG welding in modulated-spray mode, of aluminum, particularly aluminum alloys, or stainless steels, in which the current is modulated at a modulation frequency of less than 60 Hz. The shielding gas contains at least 90% helium, argon or a mixture thereof and at most 1.95% of at least one minor gaseous component chosen from oxygen and carbon dioxide. This process allows effective degassing of most of the diffusible hydrogen liable to be found in the pool of molten metal and improves the appearance and quality of the weld beads thus produced on workpieces or equipment intended for the rail, sea, air, road or space transport industry or for the chemical, petrochemical, electronic, nuclear or agrochemical industries.