What is the Function of Continuous Casting Mold for Steelmaking Plant?
1. Barrier Function (mainly completed by liquid slag layer)
Isolate the contact between air and molten steel, block the secondary oxidation of molten steel, block the contact between carbon-rich layer and molten steel, avoid Carburization on the slab surface, improve the slab surface quality and reduce the loss of steel. Note: surface carburization of low carbon steel and ultra-low carbon steel will produce brittle billets.
2. Thermal Insulation (mainly completed by solid slag)
The operation environment (thermal radiation) of the plant is greatly improved, which is convenient for smooth continuous casting. The solid slag layer with sufficient thickness can give better play to the thermal insulation performance of protective slag and prevent cold steel and floating steel from condensing on the steel level of mold. Many problems and accidents will be avoided by increasing the temperature in the meniscus area of the continuous casting mold. Such as cracks, pores on the surface of the slab, etc.
3. Absorption and Melting of Foreign Matters (mainly completed by liquid slag layer)
It can effectively absorb melting inclusions (system refractory, deoxidation products, and other metal inclusions), protect its own performance from change, purify molten steel and improve the purity of slab surface.
The low viscosity of protective slag and the proper control of some components of protective slag are beneficial to slag absorption.
4. Lubrication Function
The excellent lubrication function of protective slag can greatly reduce the friction force between billet and copper wall, so as to ensure the smooth operation of billet and the continuous improvement of speed control. The improvement of speed control is related to the process. Moreover, it is directly related to excellent protective slag.
5. Control and Uniform Heat Transfer
Uniform heat transfer: the slag film cannot flow evenly between the copper wall and the billet shell, which will cause uneven heat transfer, and all cracks are caused by uneven heat transfer.
Control of heat transfer: for gold peritectic steel, the heat transfer rate should be controlled to reduce the degree of peritectic reaction, otherwise serious cracks may occur on the surface of the slab.
The good effect of the continuous casting mold is related to other chemical compositions, physical properties of raw materials, and the combination format of various raw materials. The good physical and chemical properties of mold flux, reasonable melting characteristics and stable and uniform layered structure, and certain slag layers are indispensable. They are strictly proportioned with relevant technologies (steel grade, mold size, casting temperature, and speed control), to maximize it’s function.