The main performance indexes of continuous casting mold fluxContinuous casting mold powder is a consumable raw material that directly affects the stable produ

The main performance indexes of continuous casting mold flux

Continuous casting mold powder is a consumable raw material that directly affects the stable production and the improvement of slab quality. In order to give full play to its original functions, it is necessary to ensure an appropriate slag layer structure in the crystallizer accessories, and there are several key performance indexes to judge whether it meets certain requirements.

performance index of continuous casting mold flux:

Melting temperature. The mold flux is composed of various oxides and fluorides and has no fixed melting point. The melting temperature of the mold flux is generally defined by the hemispherical point temperature of the mold copper pipe, ranging from 000 to 1200 ℃.

Melting rate. The melting speed is defined as the time required for the mold flux to change from solid state to liquid state at 1300 ℃, which is a sign of the melting speed of the mold flux. The melting speed is generally controlled by the type and quantity of carbonaceous materials or carbonates added to the mold flux.

Viscosity. The slag structure of protective slag is a silicate structure, and the tetrahedron forms a long chain by sharing two corners. When divalent or monovalent alkali metal oxides such as MgO and Cao are added to the melt, the tetrahedral network structure will be damaged, and the deformation resistance of the chain will decrease due to the increase of fracture, so as to reduce the viscosity of the protective slag.

Alkalinity. The basicity of protective slag is generally defined as the ratio of R = wcao / wsio2. It is an important index reflecting the ability of mold flux to absorb inclusions in molten steel. Increasing alkalinity is beneficial to absorb inclusions, but too high makes the crystallization temperature and crystallization ability of slag increase. Therefore, the alkalinity selection of protective slag needs to be considered in many aspects.

When casting low-carbon aluminum killed steel with medium and thin slab, the protective slag has its unique performance requirements. The protective slag layer of crystallizer accessories cannot be too thin. By increasing the content of MgO, the stability of high-temperature performance of protective slag after absorbing Al2O3 is improved. The viscosity of mold flux is increased, the melting point is reduced, and the thickness of liquid slag layer of mold flux is 8-16mm, which can effectively control the involvement of mold flux.