Classification Based on Type of Welding
Fusion welding: These processes involve fusion of the base metal to complete the weld. Fusion welds generally do not require theapplication of pressure and they may be completed with or without the addition of filler material. All the arc welding processes are covered in this category.
Solid state welding: These are processes in which the two sides of a joint are brought into intimate atomic contact either by mechanical deformation or by atomic diffusion or by a combination of both.