Solution:

Full annealing Process:

In full annealing process the steel workpiece is heated to about 30 to 500 above the critical temperature AC3, is held there until the temperature of the workpiece is uniform throughout and finally cooling the work piece at a controlled rate so that the temperature of the surface and that of the center of the workpiece is approximately the same.

Significance:

Full annealing process wipes out all traces of the previous structure, refines the crystalline structure, soften the metal and relieves the internal stresses previously set up in the metal.