Type of welding

On the basis of temperature

1. Fusion welding
2. Solid-state welding
3. Allied welding

Fusion welding-

When the workpiece is heated beyond its melting temperature during the welding process then it is known as fusion welding.
example- arc welding, gas welding, thermit welding

Solid-state welding

• In respect of solid-state welding, the following points are to be noted-
• the workpiece is not heated by using any direct source of heat
• Heavy pressure is maintained on the joint 
• some part of pressure energy may be converted into heat energy
• whatever heat is generated during the welding is not sufficient enough to raise the temperature of the workpiece up to melting temperature since the workpiece remains in the solid-state welding
• This welding process is named as solid-state welding

 Example- explosive welding, friction welding, ultrasonic welding

Allied Welding process 

• In many engineering operations in order to join two-component heating of components may not be desirable for example- joining the diode over the chief board in such cases the allied process is used as a joining process.
• In the allied process, the temperature of the workpiece is closed to the room temperature 

example- Soldering and brazing 
Type of welding process on the basis of how the gap between two workpieces is filled-

1. Autogenous process
2. homogeneous process
3. heterogeneous process

Autogenous process

• In order to join the component in the welding operation, the gap between the two workpieces is to be filled
• The gap between two workpieces are filled by three different ways
• In the SMAW electrode, itself is consumable in this case electrode material will be melted out and will be deposited in the gap.
• In many arc welding processes may not be consumable welding. Ex- TIG welding process
• In this case, is separate filler road can be provided to fill the gap
• with the help of any source of heat, in this case, some small amount of work which material itself melted out and will the deposited in the gap