Numerical Simulation Of Rolling Mill Water Glass Sand Casting Process

Casting of heavy casting steel is a complicated process with high temperature and dynamic solidification condition. As the heavy casting has some features,such as big-sized section, long-time solidification and serious contraction etc.,some defects, such as shrinkage cavity and porosity, crack and stress deformation will happen in the cast form process.Numerical simulation technology for the casting process is the frontline in casting field. The application of this technology can forecast casting defect, optimize technical parameter, thus the producing cost is reduced.By using the numerical simulation method, this thesis will combine with the sodium silicate bonded sand casting technical plan of some heavy steel cast frame to analyze the solidification and cooling process of casting, and the defect prediction will provide reliable evidence for casting production.First, the researching contents,developing situation at home and abroad of casting numerical simulation technology, and developing situation of thermo-physical parameter of material for emulation were briefly introduced.The calculating method for numerical simulation was analyzed, and the forming mechanism and forecasted evidence of casting shrinkage hole and porosity defect were introduced. The finite element theory of temperature and stress field in the process of cast solidification, and method to measure material thermo-physical parameter were concluded.Second, testing plan was designed to measure the thermo-physical parameter of sodium silicate bonded sand, temperature field distribution was measured in sand mould by using self-made easy tester. The thermo-physical parameter of sand mould in real production, such as coefficient of thermo-physical conductivity and specific heat capacity were calculated by using inverse algorithm of thermo-physical parameter, and the thermo-physical parameter for numerical simulation was obtained. Meanwhile, interfacial heat transfer coefficient of cast and casting mould in heat conducting and heat transfer coefficient was obtained, which can be applied in numerical simulation of temperature field.Third, casting technical plan of some heavy steel cast frame was introduced and the riser and chill in sodium silicate bonded sand casting was designed,3D finite element mould was established for numerical simulation to analyze temperature field in frame solidification and to predict shrinkage hole and porosity. And heat stress and residual stress distribution was analyzed in solidifying and cooling process.Finally, frame deformation was discussed and the possible crack location was forecasted.