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Normalising

  • The normalising process is a simple one that follows the basics of process annealing (used for stress-relieving of welded structures and large castings) but the cooling process occurs in still air rather than in the furnace.
  • The component to be normalised is heated at temperatures around 40°C above the critical temperature for the particular metal alloy and soaked for several hours. 
  • Cooling in still air avoids large grain size occurring due to atomic diffusion. 
  • The resultant fine grain structure is stress free and the mechanical properties generally show a decrease in overall hardness, altered ductility and increased overall toughness, i.e. impact strength.
  • Cold rolling and casting are forming processes that produce grain structures that may require normalising before the component is put into service.

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