Dissolved Gases
Hydrogen -remains in solution but can precipitate out on cooling
Oxygen - can react with the parent metal to form an oxide inclusion
- alloying elements in steel can be used to deoxidise (e.g. Mn, Si and Ti)
- precipitation increases as the temperature drops
Nitrogen - may dissolve in some metals (e.g. aluminium) and can form precipitates (e.g. AlN