Simulation Research On Solidification Heat Transfer Of Thin Slab Continuous Casting At High Casting Speed

The continuous casting process is one of the important links in the production of the iron and steel industry.The casting speed has always been an important factor restricting the efficiency and energy saving of steel production.Continuous casting is an important part of iron and steel industry.The casting speed of continuous caster has always been an important factor restricting the efficiency and energy saving of iron and steel production.The emergence and application of a new generation of thin slab endless strip rolling technology has made it possible for the continuous caster to achieve high casting speeds.The increase of the casting speed has a great influence on the heat transfer process of thin slab continuous casting solidification,which in turn affects the quality of thin slabs and rolled products.Therefore,it is important to study the solidification heat transfer process of thin slab at high casting speed,which is of great significance for the realization of thin slab endless rolling technology.Numerical simulation method can reduce costs,shorten work cycles,and can also simulate real and ideal conditions.In this paper,numerical simulation method is used to study the heat transfer phenomenon of thin slab continuous casting solidification.In this paper,a 3d model of thin slab continuous caster with high casting speed is established,and Pro CAST software is used to calculate the solidification heat transfer process of thin slab continuous casting slab,the basic law of solidification heat transfer of thin slab continuous casting slab is obtained.On this basis,the influence of molten steel superheat(15 ?,20 ?,25 ?,30 ? and 35 ?),the casting speed(4.0 m/min,4.5 m/min,5.0 m/min,5.5 m/min and 6.0 m/min)and water volume in the secondary cooling zone(0.9 L/kg,1.1 L/kg,1.3 L/kg,1.5 L/kg and 1.7 L/kg)on the temperature distribution and solidification process of the continuous casting slab was comparatively studied.And the quality of the slab produced at high casting speed was analyzed.A solidification heat transfer model for thin slab high-speed continuous casting is established.Through the simulation,the solidification heat transfer law of Q235 steel continuous casting slab at a superheat of 25 ? and a casting speed of 5.0 m/min is initially obtained.The slab temperature simulation results are compared with the on-site temperature measurement data,the heat transfer coefficient of the model is corrected,and the accuracy of the model is improved.The thickness of the slab shell at the exit of the mold is 10.2 mm.The surface temperature of the slab 12.1 m away from the meniscus is 928 ?,and the surface temperature of the cast slab 18.0m away from the meniscus is 926 ?;The measured surface temperature of the slab 12.1 m from the meniscus is 918 ?,and the measured surface temperature of the slab 18.0 m from the meniscus is 891 ?;The error between the calculated temperature and the measured temperature is less than5%.Through simulation calculations,the effects of superheat,casting speed and water volume in the secondary cooling zone on the solidification process of continuous casting slabs are compared.The degree of superheat has little effect on the solidification of the slab.For every 5 ?increase in superheat,the solidification end point of the cast slab moves forward by 0.24 m.The casting speed has a great influence on the solidification of the slab.Each time the casting speed increases by 0.5 m/min,the solidification end point of the slab moves forward by 0.87 m.The amount of secondary cooling water has a greater impact on the solidification of the cast slab.When the water volume of the secondary cooling zone increases by 0.1 L/kg,the solidification end point of the cast slab moves back by 0.22 m.The quality of the slab under different casting speeds(4.0 m/min,5.0 m/min and 6.0 m/min)was analyzed.It is found that the higher the casting speed is,the more the number and range of center porosity are.The center porosity has a certain influence on the quality of the slab.It is necessary to apply soft reduction process at the appropriate position of the slab to reduce or eliminate the shrinkage porosity defects of the slab,so as to further improve the quality of the slab.