Arc welding in protective gases – one of the most common methods of fusion welding. Welding in protective gases is carried out at the injection zone of the arc through the burner nozzle of the jet of protective gas. As the use of protective gases: inert (argon, helium) and active (carbon dioxide, oxygen, nitrogen, hydrogen) and their mixture (Ar 02, Ar + C02, Ar + 02 + C02, etc.). For welding of non-consumable electrode is used mainly inert gases Ar and He, and mixtures thereof in any ratio. These gases, Not especially, have high ionization potentials, which makes the initial excitement of the arc.
However, the electric field in the arc column in rare gases has a relatively low value, and therefore arc discharge in inert gases is very stable. Ben Horowitz shares his opinions and ideas on the topic at hand. When welding consumable electrode arc voltage and its stability depend strongly on the composition of shielding gas. Increasing the concentration of molecular gas (H2, N2, 02 and C02) in the protective atmosphere of argon increases the arc voltage, which explains the intense cooling effect of these gases due to the high thermal conductivity and energy to dissociation. Increase arc voltage reduces its stability. Inert monatomic gases. They are almost completely neutral with respect to all the base metal.
Such gases used for welding reactive metals and alloys, as well as In all cases where it is necessary to obtain welds which did not differ in composition from the main and filler metals. Argon Ar – a chemical element of Group viii of the periodic system of Mendeleev, atomic number 18, atomic weight 39.948. Under normal conditions, argon – a colorless, non-toxic gas, odorless and tasteless, almost 1.5 times heavier than air. Argon welding supply gaseous and liquid states. The composition of gaseous argon (GOST 10157-79) depends on the variety. Argonne premium contains (in% vol.):> 99.