Reduce and relieve internal stresses
Stress relieving, or stress-relief anneal, is done to low carbon grades,
including at times low carbon alloys such as A514, in order to remove
stresses that have built up in the part from flamecutting or from mechanical
flattening. This is important when the parts will go on to be ground,
machined, or fabricated. Without stress relieving, parts may develop
bow or twist as they are further processed.
Stress relieving consists of heating the parts to a temperature just
below the range at which the grain structure begins to change, usually
1100º to 1200ºF. The parts are held at this temperature long
enough to achieve a uniform temperature throughout. Then they are allowed
to cool in the furnace. Generally, no grain transformation takes place
in stress relieving.