Simulation Study On Solidification Process Of 303 Tons Ingot And Its Influencing Factors

Based on the solidification process of 303t ingot in a domestic plant,a three-dimensional mathematical model of coupling solidification and heat transfer was adopted to investigate the effects of pouring temperature,insulation material and the height of the upriser on shrinkage cavity and solidification time of the ingot.The model was verified by the temperature measurement results of the actual production process.The results show that when the pouring temperature is 1540℃,1580℃and 1620℃,the shrinkage depth of the ingot is 226mm,275mm and 328mm respectively.When the material of the insulation layer is mullite and magnesia brick,the shrinkage depth of the ingot is 275mm,463mm and 655mm respectively.When the height of the upriser is 670mm,1170mm and 1670mm,the shrinkage depth of the ingot is 346mm,275mm and 187mm respectively.Then,based on the ingot solidification and heat transfer model,the flow and mass transfer model was coupled to investigate the influence of pouring temperature,pouring speed and the height of the upriser on the macrosegregation of the ingot.The carbon concentration distribution in the ingot was verified by drilling cuttings detection.When the pouring temperature increases from 1540℃to 1620℃,the degree of carbon positive segregation at the ingot increases by about 0.02%,the solidification time at the ingot increases by about 6h,and the solidification time at the ingot increases by about 3.5h.when the pouring speed increases from 4.27t/min to 10.27t/min,the carbon content at about 2600mm of the ingot decreases by about 0.02%,and the solidification time decreases by about 3.9h.When the height of the upriser is 670mm,the positive segregation near the upriser reaches a maximum of about 0.39%.Finally,the distribution of solidification structure of ingot was calculated by cellular automata model,and the effects of nucleation parameters and pouring temperature on solidification structure were analyzed.When the pouring temperature is 1540℃,1580℃,1620℃and 1640℃,the number of nucleation on the cross section of the ingot is 667620,478285,382143 and 341794 respectively,and the average cross section area of the grains is 9.82mm~2,13.7mm~2,17.15mm~2 and 19.17mm~2.By calculating the solidification process of ingot under different process parameters,the solidification process of ingot is quantitatively studied,which provides a theoretical basis for guiding actual production.