Recovery - Recrystallization - Grain Growth

Annealing is a heat treatment process used mostly to increase the ductility and reduce the hardness of a material. This change in hardness and ductility is a result of the reduction of dislocations in the crystal structure of the material being annealed. Annealing is often performed after a material has undergone a hardening or cold working process to prevent it from brittle failure or to make it more formable for subsequent operations.

Our experienced team of metallurgists carry out such heat treatment using accurately temperature-controlled muffle furnace, for annealing responsive materials like steel, cast iron, some types of aluminum, copper and brass.

ADVANTAGES OF ANNEALING

• Improved formability: Hard, brittle materials can be difficult to bend or press without creating a material fracture. Annealing helps eliminate this risk.
• Improve machinability: A material that is extremely brittle can cause excessive tool wear. Reducing the hardness of a material via annealing can reduce the wear on the tool being used.
• Removal of residual stresses: Residual stresses can create cracks and other mechanical complications, and it is often best to eliminate them whenever possible.

STAGES OF ANNEALING

• Recovery: It is the first stage and results in softening of the metal through removal of primarily linear defects called dislocations and the internal stresses they cause.
• Recrystallization: The second stage is recrystallization, where new strain-free grains nucleate and grow to replace those deformed by internal stresses
• Grain Growth: If annealing is allowed to continue once recrystallization has completed, then grain growth (the third stage) occurs where microstructure starts to coarsen.

APPLICATION OF ANNEALING

• Work-hardened materials such as sheet metal
• Cold drawn bar stock.
• Drawn metal wire to reduced size
• Machined products
• Welded components