Numerical Simulation Of The Quality Defects Of H Section Continuous Casting

The traditional production processes of H-sections include welding fabricationand roll forming, but the welding section has inferior and unsteady quality because ofnon-uniform stress. In addition, the traditional rolling technology has high cost due toits long process. But the near-net shap casting can avoid the shortages both from thewelding section and the traditional rolling technology.Based on the beam blank continuous casting production line of ShougangChangzhi Steel Incorporated Company in the dissertation, the research aims at solvingthe quality defects of the beam blank in production. The main work of dissertation issome researches on steel flow field, temperature field and the distribution of solidifiedshell in mold by numerical simulation. By analyzing the relationship between steelflow field, temperature field, the distribution of solidified shell and the quality defectsof beam blank, some theoretical guidance is provided for the quality defects of beamblank in Shougang Changzhi Steel Incorporated Company.Main research work is as follows:(1) The mathematical model of the mold is established based on the actualparameters of Changzhi Steel beam blank production, and the numerical simulation iscarried out for flow field, temperature field and distribution of solidified shell in themold. The relationship of steel flow field, temperature field, the distribution ofsolidified shell and the quality defects of beam blank is analyzed in order to reduce thequality defects of beam blank.(2) Keeping the other parameters still, and the effects of structure of thesubmerged entry nozzle on steel flow field, temperature field, the distribution ofsolidified shell in H-form mold have been studied, and the characteristics of metallurgical phenomenon are obtained respectively in the different outlet molds.(3) Keeping other conditions still, the influence rules of steel flow field,temperature field, the distribution of solidified shell have been studied by changing thecasting speed, outlet angle, nozzle immersion depth and outlet opening arearespectively. Some theoretical directions to optimizing parameters and solving qualitydefects are thus provided.The results show that due to the strong jet impingement on the solidified shell inthe mold of straight-through type double nozzle, the jet impingement is very deep,which leads to the fact that the inclusion is hard to float, and it has not enough heat toslag on the liquid level. It is found that the problems arising through straight-throughtype nozzle casting can be better eliminated by using the three-side outlets. Accordingto the studies on the process parameters, the lower the casting speed in a certain rangeis, the more favorable it is for the even growth of the solidified shell. This papersuggests that the casting speed should be0.8m/min, and the better outlet immersiondepth is about100mm. In addition, the outlet angle should be steadily around-15°.At last, it is suggested that the opening area of outlet should be as large as possibleunder the premise of ensuring the quality and life of nozzle.