|Disclaimer: The information on this page has not been checked
by an independent person. Use this information at your own
risk.| Click arrows to page adverts Steel often requires heat
treatment to obtain improved properties e.g increase hardness or
strength, or to neutralise negative effects resulting from
previous manufacturing processes e.g.remove internal stresses
generated by fabrication processes. Normalising involves heating
the steel to about 40oC above its upper critical limit. The
steel is then held at this temperature for a period of time and
is then cooled in air.. It is desireable that the temperature of
the steel shall be maintained for a time period more than 2
minutes per mm of section thickness and shall not exceed the
upper critical temperature by more than 50oC. Anealing is
reheating steel followed by slow cooling. It is completed
Hardening involves heating a steel to its normalising
temperature and cooling (Quenching ) rapidly in a suitable fluid
e.g oil, water or air. This process involves