The primary purpose of annealing is to soften previously hardened metals, or following forging operations, etc. and to restore the original microstructure, homogeneity, and improve machinability in preparation for critical/delicate operations or heat treatment. A full anneal on raw material after roughing operations has also been known to be very beneficial in controlling distortion during subsequent hardening operations.

Precautions are essential as some previously hardened steels are quite sensitive to thermal shock, the surface must be protected against loss of carbon and the work well supported as annealing temperatures are high and the time, relatively long. Then, the work must be cooled at the appropriate rate.