Annealing and normalising are two ways of heating steel. Annealing softens the steel, preparing it for shaping and forging. Normalising is a similar process but hardens the steel once you have finished working on it. Both processes require heat from a furnace or kiln. However, with normalising you heat the steel to a higher temperature and allow it to cool quicker than you would with annealing. The heating and cooling process changes the molecular structure of the alloy and therefore its malleability and strength. (See Reference 1)
- Skill level:
Things you need
- Annealing furnace or electric kiln
- Heat-resistant tongs
- Protective eye wear
- Protective gloves
- Insulating material, for example ashes (optional)
- Magnet (optional)
Heat your annealing furnace or electric kiln to 760 degrees Celsius. Ensure you have put on the appropriate protective eye wear and clothing. (See Reference 3)
Place the steel in the furnace using the tongs. Watch the steel until it turns a bright red colour and leave it in this state for three to five minutes. (See References 2 and 4)
Turn off the furnace and leave the steel to cool slowly inside. Alternatively, you can remove it and bury it in insulating material, such as ashes so that it cools slowly. (See References 1 and 3)
Heat the furnace or kiln to 816 degrees Celsius and put on your protective eyewear and clothing. (See Reference 2)
Calculate the amount of time you will need to leave the steel in the furnace. You can do this by allowing an hour for every cubic inch of steel you are normalising. (See reference 2)
Place the steel in the furnace and leave it for the calculated time.
Remove the steel from the furnace once the time is up using the heat-resistant tongs and leave it to cool in the open air.
Tips and warnings
- You can test whether your steel has reached the optimum temperature for annealing by placing a magnet on the metal before putting it in the furnace. Due to the changes in the alloy's chemical structure during the heating process, annealed steel loses its magnetism. Therefore, once the steel has annealed, the magnet will no longer stick to the metal. (See Reference 3)
- Always conduct your metalwork outside or in a well-ventilated area.
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