What is the difference beween annealing and stress relief of carbon steel? what are the changes occurring in the structure of the steel in each?

Annealing of carbon steel is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and to make it more workable. It involves heating a material to above its recrystallization temperature, maintaining a suitable temperature, and then cooling. Annealing can induce ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold working properties.

Stress Relieving of carbon steel consists of heating the steel to a temperature below the critical range to relieve the stresses resulting from cold working, shearing, or gas cutting. It is not intended to alter the micro-structure or mechanical properties significantly.also a process for making material softer. However stress relieving does not change the material properties as does annealing and normalizing.