Subcritical annealing treatment is applied to a broad range of
alloys and parts to produce a softened condition without the microstructure
refinement that takes place in full anneal or normalize heat treatments.
The process is usually applied to castings and
forgings. Subcritical
annealing is performed in in the temperature range of 1300 to 1400 oF
in batch or continuous furnaces either with or without protective atmosphere.