Non-consumable electrode arc welding

Arc welding This is a classic metal welding process that uses an electric arc to heat and melt the metal surface. The arc temperature is high enough, up to 7000 ^° C, to melt metals of varying hardness. As early as 1802, scientists discovered the phenomenon of a high-temperature electric arc. And in 1882, scientist N.N. Benardos invented and patented electric welding, using a carbon electrode. Arc welding There are two types of welding: one with a consumable electrode and one with a non-consumable electrode. The non-consumable method uses a temperature-resistant material. Suitable materials for this purpose include tungsten, carbon, or graphite electrodes.

Basic principles of electric arc welding with a non-consumable electrode

Non-consumable electrode arc welding This allows for maintaining high arc stability, regardless of the current type. Also, by adjusting the feed rate and electrode angle, and selecting the filler wire grade, one can change the chemical composition of the weld and its geometric parameters. Non-consumable electrode arc welding It has a wide range of applications for welding various metals. It successfully welds:

• carbon steels, low-alloy and high-alloy;
• heat-resistant steels and alloys;
• non-ferrous metals and their alloys.

Welding technologies for different types of metal vary in their specifics, but the basic parameters are similar. For example, the technology for welding carbon and low-alloy steel:

• The workpiece is thoroughly cleaned of scale, rust, and dirt. This ensures good contact between the electrode and the metal surface being welded;
• Current parameters are selected. Direct current with straight polarity is typically used. The electrode is the negative terminal, and the workpiece is the positive terminal. The voltage is calculated for 1 mm of tungsten electrode diameter, with a voltage of 30–35 A. The welding arc should be short. This promotes deep penetration.
• Welding is performed with the angle facing forward. Steel grades 10 and 20 are welded only with filler wire, otherwise the weld may become porous. To prevent filler metal spatter and oxidation of the wire tip, avoid sudden movements of the wire.

Carbon electrode

When welding with such an electrode, a protective environment is formed by the burning and subsequent evaporation of the electrode. A unique atmosphere containing CO is created.₂, CO, and carbon vapor. However, for welding critical parts, additional means are used to enhance the gas shielding of the metal being welded. Carbon electrode welding is used for surfacing and welding: steel, cast iron, hard alloys, and non-ferrous metals.

Tungsten electrode

Tungsten electrodes are more commonly used than carbon electrodes. They are quite wear-resistant. Rod consumption is 1-2 cm per hour of arc burning. To prevent rapid electrode oxidation, they operate in a shielding gas. Helium and argon are used for this purpose; they do not react with tungsten. This electrode can effectively join metal sheets up to 6 mm thick, as well as very thin ones (less than 0.1 mm). The weld seam is clean. Non-consumable electrode arc welding allows high-quality welding of parts made of highly active and refractory metals.