Welding can be defined as the process of joining two metal parts by applying heat .
In industry, welding process is primarily used for fabricating works.
Welding is useful in making permanent joints. It can be performed by applying or not applying pressure. The contours of the metal parts are molten to make the joint in some methods. In some types of welding processes, filler metal is used. In some other methods, filler metal is not used.
The process of welding finds application in manufacturing automobiles, aeroplanes, rail coaches, machine components, metal structures, boilers and ships. Generally, welding process is applied wherever metal works are performed.
Methods of Welding
There are two methods by which welding is performed
- Plastic welding
- Fusion welding
In this method, the metal parts are heated to plastic state. At this stage, pressure is applied to make a perfect joint. It is also known as pressure welding.
The metal parts are heated upto the point of melting in this method. The joint is made at this stage and the parts are allowed to cool. On cooling, the molten metal forms a solid joint. No pressure is applied in this method. Hence, it is also known as prersure less welding. Arc welding and gas welding fall in this category.