Metal welding, methods

Welding involves joining two dissimilar metals by intensely heating them, deforming them, and then fusing the interatomic bonds, resulting in a permanent joint. Currently, welding employs many methods, approximately 100 in total. Different types of welding are classified by physical, technical, and technological characteristics.

Physical characteristics include:

• thermal welding of metals;
• thermomechanical;
• mechanical.

Thermal welding is a type of welding that uses heat energy. These include gas welding, arc welding, plasma welding, and others.

Thermomechanical welding refers to a type of welding that uses thermal energy and pressure.

Any process that uses mechanical energy is called mechanical welding. Examples include cold welding, explosion welding, friction welding, and ultrasonic welding.

According to their technical characteristics, there are types of welding:

• by the method of protecting the metal in the welding zone (in a vacuum, in air, in foam, under flux, in a protective gas);
• by the duration of the process (intermittent and continuous);
• by degree of mechanization (mechanized, automated, automatic, manual);
• protective gas (in inert gases and in active gases);
• the nature of metal protection in the welding zone (in a controlled atmosphere or with jet protection).

Metal welding, methods

According to technological characteristics, it is established for each type separately, since their operating methods differ.
Arc welding. This involves melting metal edges with an electric arc, which creates intense heat and melts the metal.

There are some types of this welding:

1) Manual arc.

• Consumable electrode welding is a classic welding method in which the electrode melts and the edge of the workpiece forms a pool of molten metal. Upon cooling, a weld is formed;
• A non-consumable electrode, either carbon or graphite, strikes an arc between the workpiece and the filler metal, creating a pool of liquid metal that then solidifies. It is used for welding non-ferrous metals.

2) Semi-automatic and automatic submerged arc welding.

• The arc is fed and then moved along the specified contour of the edges being welded. The flux protects the weld from external oxygen exposure. The weld quality is excellent.

3) Arc welding, when the metal is in a protective gas.

• Welding is performed with a non-consumable electrode (tungsten) or a consumable electrode. In this case, the electrode melts and a weld is formed; in non-consumable welding, the weld emerges from the molten metal of the workpiece; sometimes, a filler material is added. A powerful jet of shielding gas displaces atmospheric air, protecting against oxidation.

4) Electroslag welding.

• is carried out by melting the metal of the welded edges of the product.

Refractory and chemically active metals and their alloys are increasingly being used in industry. Joining them requires new types of metal welding, methods that have successfully accomplished this task. To achieve this, welding techniques have been developed that ensure exceptionally high-quality welds and utilize highly concentrated heat sources.