Annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material above its recrystallization temperature, maintaining a suitable temperature for a suitable amount of time, and then cooling.
In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to a change in ductility and hardness. As the material cools it recrystallizes. For many alloys, including carbon steel, the crystal grain size and phase composition, which ultimately determine the material properties, are dependent on the heating, and cooling rate. Hot working or cold working after the annealing process alter the metal structure, so further heat treatments may be used to achieve the properties required.
With our knowledge of the composition and phase diagram, heat treatment can be used to adjust between harder and more brittle, to softer and more ductile material.
we have annealing electrically heated furnaces (controlled by pid controllers), with controlled atmosphere for spheroidised annealing of wire rods & bars without addition of any decarburisation. With the help of a ammonia cracker, nitrogen generator and oximeter, the atmosphere is maintained.