Welding Process:There are many definition of a welding process. But the most comprehensive definition is below.

Welding is defined as a "a localized coalescence of metals, wherein coalescence is  obtained  by  heating  to  suitable  temperature,  with  of  without  the  application  of pressure and with or without the use of filler metal. The filler metal has a melting point approximately the same as the base metals."The welding process is used to metallurgical join together two metal pieces, to produce essentially a single piece of metal. The process results in what is known as a 'permanent joint.' A good welded joint is as strong as the parent metal. The product is known as 'Weldment.'