Fusion welding
Fusion welding is a generic term for welding processes that rely upon melting to join materials of similar compositions and melting points. Due to the high-temperature phase transitions inherent to these processes, a heat-affected zone is created in the material (although some techniques, like beam welding, often minimize this effect by introducing comparatively little heat into the workpiece).
In contrast to fusion welding, solid-state welding does not involve the melting of materials.
Fusion welding was a key factor of in the creation of modern civilization. It is also very important for maintaining civilization. Fusion welding holds a key role in construction. Besides bolts and rivets there are no other practical method for joining pieces of metal securely. Fusion welding is used to make many everyday items. From construction to airplanes to cars fusion welding is very common. Another common use of fusion welding is in artwork. There is a large community that uses both arc and flame contact welding artwork.
Arc welding is one of the many types of fusion welding. Arc welding joins two pieces of metal together by using an intermediate filler metal. The way this works is by completing an electrical circuit to create an electrical arc. This electrical arc is 6500oF in its center. This electrical arc is created at the tip of the filler metal. As the arc melts the metal it is moved either by a person or a machine along the gap in the metals creating a bond. This method is very common as it is typically done with a hand held machine. Arc welding machines are portable and can be brought on to job sites and in hard to reach areas. Arc welding is also the most common method of underwater welding. Electrical arcs form between points separated by a gas. In the process of underwater welding a bubble of gas is blown around the area being welded so that an electrical arc may form. Underwater welding has many applications. Ship hulls are repaired and oil rigs are maintained with underwater arc welding.
Resistance welding is done using two electrodes. Each electrode comes into contact with one of the pieces being welded. The two pieces of metal are then pressed together between the electrodes. While they are being pressed an electric current is ran through them. As this happens the pieces of metal begin to heat up at the point where they come into contact. The current is passed through the metal until it is hot enough to the point where the two pieces melt and conjoin. As the metal cools the bond is solidified. This process requires large amounts of electricity. In most cases transformers are needed to provide enough Amps. Resistance welding is a very prevalent form of fusion welding. Resistance welding is used in the manufacturing of automobiles and construction equipment.
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