The protective slag in the continuous casting process acts vital role.
Continuous casting protection slag can inhibit the formation of bridges and crusts in the mould in the process of continuous casting, and can improve the temperature of the bending moon surface, so that the billet bending moon surface at the billet shell growth smoothly, but also to make the bending moon surface has a larger radius of curvature, so that the mould in the lower part of the steel floating bubbles and oxide inclusions are not easy to be captured by the bending moon surface, easier to float to the liquid slag layer.
Protective slag in the steel under the action of high temperature, will quickly form a liquid slag layer, can prevent the diffusion of air to the steel surface. The three-layer structure of the protective slag on the oxygen, nitrogen isolation, so that the steel from secondary oxidation and absorption of nitrogen, to avoid the oxidation of alloy elements in the steel.
In order to reduce the occurrence of cracks and steel leakage accidents and improve the service life of the mould, the mould copper plate and the billet must be well lubricated to reduce friction, to avoid causing steel leakage and billet cracks.
In the internal of the mould the billet shell shrinkage produced air gap, so that the thermal resistance increases. The air gap is filled with uniform slag film after adding protection slag, can reduce the air gap thermal resistance, significantly improve the heat transfer of the mould, so that the billet shell grows evenly.
In the continuous casting protection slag add ionic radius relatively large Na +, K +, Ba2 + and other alkali metal compounds can reduce the viscosity of the protection slag, improve the ability of the liquid slag to absorb inclusions.
