Aluminum dissolves in γ iron to about 0.6%, slightly more in austenite containing carbon, solubility in α iron goes
up to about 30%. Aluminium is used as a strong deoxidizer binding nitrogen in AlN, stops the growth of austenite,
removes the tendency to aging of soft steel. The addition of Aluminium increases the resistance of heat resistant
and chrome steel to oxidation, is also used as an addition to steel for nitriding, allowing a strong hardening of the
surface by nitriding at about 500C.
