Simulation Study On Solidification Structure And Internal Quality Of Billet Continuous Casting

The solidification structure and internal quality affect the properties of the cast billet.Some key parameters are used to simulate the solidification process of liquid steel,using simulation software Pro CAST to simulate the temperature distribution of casting billet surface and center in continuous casting process,using the CAFE module of the software to simulate the billet solidification process,and according to the shrinkage criterion of software to predict the shrinkage defects in the casting.There is relationship among the temperature distribution of casting solidification process with secondary cooling conditions and pouring temperature and casting speed.When the heat transfer coefficient of the mold is constant and the drawing speed is certain,the cooling effect is gradually weakened of from No.1 to No.4 in the process,and the temperature of the casting billet is increased in turn.The center temperature of the billet is 1156?,1194?,1268 ?and 1322?,respectively.The cooling effect of the secondary cooling zone is very important for the solidification of the billet.The content of elements has an effect on the solidification structure of the cast billet.When the content of carbon is increasing from 0.14% to 0.22%,the grain refinement gradually increased,so the fineness of the billet was the highest when the content of C was 0.22%.When the content of silicon is 0.16%,the number of medium-axis grains is more,so the refining degree is better.When the Mn content in steel increases from 0.34% to 0.42%,the average area of grain increases,and the grain is coarse and the effect of grain refinement is not good.Generally speaking,the grain size is better when the content is 0.34%.When pouring temperature is raised from 1535 to 1555? ?,the defects size is 14.4mm,11.3mm and 14.3mm,respectively.When the drawing speed is increased from 1.5m/min to 2.5m/min,the quantity of defects in the billet increases,and the shrinkage size is 11.4mm,11.5mm and 15.3mm,but the porosity of the billet decreases.When the carbon content is increased to 0.22%,the porosity is 49.27%,47.08%,50.12%,48.75% and 52.10%,respectively.Therefore,with the raising of carbon content,the porosity of the billet is increasing on the whole.