12 September 2020

Difference between full annealing and process annealing

What is the full annealing process?

Annealing is a heat treatment process in which the material is taken to a high temperature kept there for some time and then cooled in a furnace. Cooling is done slowly to avoid the distortion.

What is process annealing?

Process annealing is a heat treatment that is often used to soften and increase the ductility of a previously strain hardened metal. Ductility is important in shaping and creating a more refined piece of work through processes such as rolling, drawing, forging, extruding, spinning, and adding. 

So here this article gives the main key difference between full annealing and process annealing to better understand this topic.

Difference between full annealing and process annealing:

Full annealing:
  • Heat 30 to 50 °C above its critical temperature, keep it at that temperature for while then slowly cooled down.
  • Suitable in low mild steel as well as in high carbon steel.
  • Phase transformation occurred during the full annealing process. The resulting crystal structure laminated perlite.
  • The resulted metal is more ductile, and this process is used in steel for deep-drawing operation.
Process annealing:
  • Steel heated below the critical temperature, keep it at that temperature for while then cooled slowly, also called as subcritical annealing. 
  • Suitable for low carbon steel.
  • Phase transformation not involved in this process. The material is in the same phase is throughout the process.
  • Process annealing is cheaper than full annealing. 
  • Used in sheet metal and wire industries.