On the one hand, oxygen is needed during the heating process of molten steel, and it is also needed to produce chemical reactions with carbon, sulphur and other harmful substances in molten steel to improve the quality of steel. On the other hand, oxygen molecules in molten steel will affect the mechanical properties and strength of steel. Therefore, steel should be deoxidised, which is a very important part.
- During the solidification of steel, oxygen will precipitate in the form of FeO, distributed on the grain boundaries, reducing the plasticity and other mechanical properties of steel. In addition, the oxygen dissolved in the molten steel will form oxides with other elements in the steel, and these oxides will affect the plasticity, toughness and welding properties of the steel.
- In the solidification process, as oxygen solubility decreases, more than the carbon-oxygen equilibrium value of excess oxygen will react with carbon to generate CO bubbles, which will reduce the purity and properties of steel.
- Oxygen during solidification exacerbates the hot embrittlement hazard of sulphur in steel.
