Question

Which two of the following joining processes are autogenous?

i. Diffusion welding

ii. Electroslag welding

iii. Tungsten inert gas welding

iv. Friction welding

1. i and iv
2. ii and iii
3. ii and iv
4. i and iii

Answer 1

Correct Answer - Option 1 : i and iv

Welding is a process of joining two similar or dissimilar metals by fusion, with or without the application of pressure and with or without the use of filler metals. The fusion of metal takes place by means of heat. The heat may be obtained from electric arc, electric resistance, chemical reaction, friction or radiant energy.

Based on the composition of joints, the joining process may be classified as:

Autogenous Welding: The process of joining similar metals by melting the edges together, without the addition of filler metals. Ex. Friction Welding, Diffusion Welding, Laser Beam Welding, Electron beam welding, Resistance Welding. 

Homogeneous Welding: The process of joining similar metals with the help of a filler rod of the same metal. Ex. Gas Metal Arc Welding, Electroslag Welding, Submerged Arc Welding.

Heterogeneous Welding: The process of joining dissimilar metals using a filler rod. Ex. Plasma Arc Welding, Friction Stir Welding.