Numerical Simulation Of Heavy Plate Slab And Supe-Large Round Billet During Continuous Casting

The crack and even the breakout usually occurs during the continuous casting process,especially the large size and high level steel. Meanwhile it is the major problem to preventthe smoothness of continuous casting production and the new steel continuous castingtechnology research and development, and it is unable to study the high temperaturesolidification process of the large size casting slab due to lack of corresponding theoreticalresearch and experimental instrument.Basing on the above problems a commercial ANSYS finite element model has beenestablished to simulate the high temperature solidification process during the mold and thewhole continuous casting of the300mm Q345D slab. At the same time it also makes aresearch on the temperature field distribution and shell growth situation for450,600round billet. A kind of experimental device for studying the high temperature phasetransformation was designed according to the Fe-C alloy solidification characteristics. Bywhich it can get high temperature solidification organization at a high quenching coolingrate. Finally it can get high temperature solidification transformation laws by analyzing thehigh temperature solidification organization.The results indicate that the increases of δ ferrite content, casting speed and degree ofsuperheat can give rise to the whole surface temperature of mold along the castingdirection and the shell thickness show a periodic fluctuation which occurs below themeniscus180mm, and the period is about100mm. In addition, when the casting speedreaches to1.0m/min, the degree of superheat achieves40℃, the δ ferrite content during theperitectic reaction arrives at100％, the amplitude of fluctuation of surface temperature andshell thickness will be the greatest which occurs below the meniscus425mm, which thetemperature difference is364.49℃, meanwhile, the shell thickness difference is6.17mm. Itis easy to produce air gap defect in the mould on this condition, which should be paidmuch more attention during production. In addition, raising the casting rate properly、 decreasing the degree of superheat and increasing the distance of second cooling zone canpromote the process of continuous casting, reducing the defect of the slab, improving theproductive efficiency during the continuous casting process. Comparing the surfacetemperature between the calculated value and the actual date provided by the Wugang steelplant turns out that the calculated results is reasonably in good agreement with the on-sitetest data, and the relative error is less than5％. The comparison between450and600round billet shows that continuous casting process parameters has a greater influence onthe temperature field distribution and shell growth situation for600super-large roundbillet. By taking some relative measures to control the temperature and cooling rate tocontrol the high temperature solidification phase transformation and the proportion. Andthen the high temperature solidification microstructure can be reserved by quenchingwith ice water and salt at target temperature, meanwhile, the high temperaturesolidification phase transformation laws can be obtained by the later microstructurequantitative analysis.It largely enrich the research field blank on large size and easy to crack of heavy plateslab or super-large round billet, and it also provides an experimental apparatus to measurethe solidification performance of steel materials which greatly enrich the laboratorymeasurement of solidification theory. It is of great significance in improving continuouscasting process, reducing slab cracks and improving the slab quality.