|Al||Melting point 660 °C||Aluminium|
This is the most powerful, very frequently used deoxidizing and also detriding agent. As a result, it also has an extremely favourable effect on resistance to ageing. Small additions assist fine-grained structure. As Al forms very hard nitrides with nitrogen, it is usually an alloying element in nitriding steels. It increases scaling resistance and is therefore frequently added to alloy ferritic heat resistant steels. With unalloyed carbon steels, scaling resistance can be promoted by calorizing (introduction of aluminium into the surface). Al very sharply restricts the γ-phase. On account of the very pronounced increase in coercive field intensity, Al is an alloying element in iron-nickel-cobalt-aluminium permanent magnet alloys.