Precipitation Harden Or Age Hardening
Precipitation Hardening or Age Hardening. There are certain alloys [commonly some types of stainless steels, Aluminium and copper-based alloys] that will through harden by this method. The treatment typically involves a solution treatment which is carried out at high temperature followed by one or more ageing treatments at lower temperatures to achieve the correct hardness [Note. The material only hardens after the ageing treatment].
Care must be taken to purchase the material in the best state for manufacturing the component and ensuring that this information is communicated to the heat treater.
Typical states for purchasing Precipitation hardened alloys would be:-
- the normalised state, [lowest price but requires full heat treatment]
- the solution treated state, [only requires ageing treatment so distortion is minimised]
- the over aged condition [no further heat treatment required but the metal is soft enough for machining operations]
Care should be taken in specifying the ageing condition as this can often effect the corrosion resistance.