What are the three principal types of welding?

The three principal types of welding are categorized based on the energy source used to generate the heat necessary for the welding process. Gas Welding, Electric Arc Welding, and Electric Resistance Welding represent three foundational techniques in the welding industry.

Gas welding involves the use of a flame produced by burning a fuel gas, typically acetylene, combined with oxygen. This process is commonly used for repairing and brazing different metals due to its portability and effectiveness on thinner materials.

Electric arc welding employs an electric arc to melt the materials being joined. This technique is widely used in various applications, from structural welding to automotive production, because of its versatility and the strong welds it produces.

Electric resistance welding relies on the heat generated by electric resistance to join metals. This method involves passing an electric current through the workpieces, heating them to a molten state, and applying pressure to fuse them together. It is commonly found in automotive and manufacturing operations, especially for mass production.

The other options, while including valid types of welding, do not encompass the three fundamental categories that form the core of welding practices. Each of the types listed in those options serves specific needs but does not capture the breadth of the principal welding techniques.