Heat Treatment of Metal
heating and cooling metals to change their properties
Work Hardening
increases strength
but makes more brittle
annealing
heating metal up after hardening to make it soft again - less brittle
case hardening
carbon added to the outside case of steel
- Heat steel - red hot
- Dip in compound (carbon)
- Heat again and then quench in cold water
Tempering
deforming / hitting - changes the molecular structure
easier to work with
e.g. Jewellery
heat metal
quench in oil
makes it less brittle