In continuous casting, low corrosion resistance often occurs, which directly leads to uneven composition and will eventually affect the smelting quality. In order to avoid the problem of central segregation, we need to take some preventive measures, so as to more effectively ensure the whole production operation.
1. Cooper mould tube manufacturers introduced that in order to prevent central segregation of continuous casting, the purity of molten steel needs to be improved.
It is necessary to improve the hit rate of carbon in converter production and accurately control the carbon content in molten steel. S and P in molten steel are easily segregated elements. Their content and distribution in molten steel affect the central segregation and central porosity of the billet. By smelting clean steel, such as hot metal pretreatment or ladle desulfurization, the content of easily segregated elements such as s and P in molten steel can be reduced and the purity of molten steel can be improved, which can effectively prevent the occurrence of central segregation and central porosity.
2. Control the bulge of the slab.
When designing the continuous caster, a close row roll arrangement with a small roll diameter shall be adopted as far as possible to reduce the roll spacing; Rigid multi-section rollers are used to prevent the deformation of backup rollers. The continuous caster should not be too high, so as to reduce the height of the liquid phase cavity and reduce the static pressure of molten steel. The pinch rollers in the secondary cooling zone should be strictly aligned in production.
3. Control pouring temperature and drawing speed.
When producing low carbon steel (C ≤ 0.08%), the standard superheat of molten steel in molten steel tank and tundish shall be controlled within 600℃ and 300 ℃ respectively. When producing peritectic steel and medium carbon steel (0.08% ≤C≤ 0.30%), the target superheats of molten steel in molten steel tank and tundish shall be controlled within 550 ℃ and 250 ℃ respectively.
We should also pay attention to the slag inclusion on the surface of the billet. If it is not removed in time, it will often cause surface defects of the finished product. In addition, the thermal conductivity of the slag is poor, and the solidified shell at the slag inclusion is thin, which will cause leakage accidents.