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Other kinds of welding


Spot welding - точкове зварювання forge welding – ковальне зварювання

Some kinds of welding do not use an electric arc. They might use a flame, electricity without an arc, an energy beam, or physical force. The most common type of welding that does not use an arc is called gas welding. In gas welding, a flammable (meaning it will burn) gas and oxygen are combined and burn at the end of a torch. Gas welding does not need any special shielding because a flame which is adjusted right has no extra oxygen in it. It is still important to make sure the metal is clean. The flame heats up the metal so much that it melts. When both the pieces of metal are melted at the edge, the liquid metal becomes one piece.

The other kind of welding that does not use an arc still uses electricity. It is called resistance welding. With this kind, two pieces of thin metal are pinched together and then electricity is made to go through them. This makes the metal get really hot and melt where it is pinched together. The two pieces melt together at that place. Sometimes this is called spot welding because the welding can only happen at one small place(or spot) at a time.
Forge welding is the very first kind of welding that ever was used. Forge welding needs the two pieces of metal to so hot that they almost melt. Then they are beat together with hammers until they are one piece.
The other kinds of welding that do not use an arc are hard to do, and usually new. They are expensive too. Most of these kinds of welding are only done where specially needed. They might use an electron beam, laser, or ultrasonic sound waves.
Types of Welding


Non – consumable Electrode Arc welding

As a non – consumable electrodes tungsten or carbon electrodes can be used. In gas-tungsten arc welding a tungsten electrode is used in place of the metal electrode used in shielded metal-arc welding. A chemically inert gas, such as argon, helium, or carbon dioxide is used to shield the metal from oxidation. The

heat from the arc formed between the electrode and the metal melts the edges of the metal. Metal for the weld may be added by placing a bare wire in the arc or the point of the weld. This process can be used with nearly all metals and produces a high – quality weld. However, the rate of welding is considerably slower than in other processes.
Shielded Metal Arc weldingIn shielded metal-arc welding, a metallic electrode, which conducts electricity, is coated with flux and connected to a source of electric current. The metal to be welded is connected to the other end of the same source of current. An electric arc is formed by touching the tip of the electrode to the metal and then drawing it away. The intense heat of the arc melts both parts to be welded and the point of the metal electrode, which supplies filler metal for the weld. This process is used mainly for welding steels.
Gas –metal Arc weldingIn gas-metal welding, a bare electrode is shielded from the air by surrounding it with argon or carbon dioxide gas and sometimes by coating the electrode with flux. The electrode is fed into the electric arc, and melts off in droplets that enter the liquid metal of the weld seam. Most metals can be joined by this process.