The function and function of continuous casting mold powder
In the early stage of the continuous casting process, the casting method was open casting, and rapeseed oil was used for protection casting. Higher requirements, rapeseed oil can no longer meet the development needs of continuous casting, in order to adapt to the development of continuous casting technology, continuous casting mold was developed in the 1960s. Continuous casting mold powder
plays an important role in the continuous casting process. In the process of exerting its function, there are many key stages. In each stage, continuous casting mold powder must play a good role, otherwise it will reduce the performance. Surface and internal quality of continuous casting slabs. The selection and application of suitable continuous casting mold powder can prevent quality defects such as longitudinal cracks on the surface of continuous casting slabs, and prevent accidents such as bonding and breakout during continuous casting production.
In the continuous casting process, after the mold slag is added to the mold, it is sintered and melted on the molten steel surface to form a liquid slag layer. When the mold slag near the liquid slag layer has not reached the melting temperature, it has been sintered into a transition layer. Above the transition layer is the original (solid) slag layer, which is the three-layer structure of what we usually call mold slag—liquid slag layer, sintered layer, and original (solid) slag layer. The above-mentioned liquid slag and molten steel form a meniscus near the mold wall. Under the action of mold vibration, gravity and capillary adsorption, the liquid slag flows into the gap between the mold wall and the shell through the meniscus to form a slag film. , the liquid slag pool on the molten steel surface and the consumption of liquid slag between the mold wall and the billet shell form a dynamic balance.
The mold slag has the following five functions in the continuous casting mold:
1. Thermal insulation reduces heat loss of molten steel
2. Isolate the air to prevent secondary oxidation
3. Lubricate the billet to reduce the sticking of the billet
4. Improve the heat transfer of the mold
5. Absorb non-metallic inclusions