Cooling Process Simulation Of Fused Cast Zirconia-Alumina Material

Fused cast AZS refractory is the extremely important material to build glass furnace.Due to the deceleration of development in glass industry and the application of newglass melting technologies,the requirementfor refractory is more rigour.Using software COMSOL Multiphysics, the influences of mold material and its thickness on temperature, conductive heat flux and thermal stress distribution during the cooling process can be analyzed qualitatively with low cost and short time to reduce cracks and raise the qualified rate of products. The results showed that:(1) The solidification sequence of casting gradually extended from corner to casting center, making crystal grain of casting gradually enlarge from corner to geometric center; the increasing of mold thickness would lead to shorter complete solidification time and increase the larger conductive heat fluxdistribution area, as well as was helpful for rapid cooling and forming the uniform crystal structure of material. The mid-term thermal stress peak appeared at1/4and3/4length of casting surface respectively, where was easy to crack.(2) Among the four kinds of mold, SiO2mold made the cooling speed the slowest and the thermal stress concentration most serious. The mid-term thermal stress peak reached up to227MPa when using4cm sand mold.(3) By using corundum mold, the temperature and heat flux distribution of casting were uniform and the cooling time was short, which were helpful to form the fine crystalline structure of material. The optimum thickness of corundum mold was5cm-6cm. The peak of maximum thermal stress decreased to125MPa in mid-term, which would be favorable to reduce surface cracks and improve qualified rate of products.(4) Increasing the mold thickness could make the casting surface crystallize uniformly and the casting cool in shorter time, while the peak of thermal stress decreased. So cast iron mold could help to reduce cracks and improve qualified rate of products.(5) When using graphite mold, solidification time was long. The maximum heat flux distribution was not better than using cast iron and corundum In comparison with cast iron or corundum, graphite made the casting thermal stress increase in med-term, which was unfavorable to reduce the cracks.(6) Out of four kinds of materials, corundum and cast iron mold could make the casting cool in shorter time, distributing heat flux uniformly and having the lowest thermal stress in cooling med-term, so as to decrease cracks and form uniform material structure. If considering the pollution of mold to casting surface, corundum mold was the best to choose. Compared the simulation results with the literature simulation results and the actual production situation, the model and the simulation result were verified.