Optimization Of SEM Structure In Slab Mold For Continuous Casting

Mold is a key metallurgical vessel in controlling the quality of slab. Technological parameters of mold result in good or bad slab. Reasonable parameter can reduce defect of casting slab and improve its quality. Contrarily, some defect such as inclusion and surface crack will be generated. Indeed, some production accident such as breakout may happen. The flow behavior plays an important role in controlling the quality of casting slab in mold. So, controlling the flow behavior of liquid steel is necessary. Structure of submergence entry nozzle (SEN) is a key factor of influencing flow behavior. Influence of submergence depth, port angle, ratio of port area to SEN area and port section form on flow behavior is important. So, it is significant to research and optimize the structure of SEN.The process of continuous casting conducts in high temperature, which makes the research difficult. Physical simulation and numerical simulation are two main methods to research the continuous casting mold at present. Physical simulation, which is based on theory of similarity, is carried out by water model experiment. Numerical simulation is that physical phenomenon be simulated and calculated by software such as Ansys and Fluent.This paper use physical simulation to research the influence of submergence depth, port angle, ratio of port area to SEN area and port section form on flow behavior in220mm×1600mm,250mm×1200mm,250mm×1600mm,270mm×1200mm,270mm×1400mm,270mm×1600mm,300mm×1200mm,300mm×1600mm section slab continuous casting mold. It was found that level fluctuation decreases obviously when port area ratio bigger than2.14or2.48(different sections have different critical values) for elliptic SEN which port angle is15°or12°. Level fluctuation decreases obviously when port area ratio bigger than2.32for quasi-elliptic SEN which port angle is15°. Level fluctuation decreases obviously when port area ratio bigger than2.61for quasi-elliptic SEN which port angle is12°.This paper also use numerical simulation to research the influence of5#,7#,10#SEN parameter on flow behavior and temperature field in270mm×1600mm section continuous casting slab mold. Research found that when the submergence depth increase from100mm to220mm, the high turbulent kinetic energy zone in top of mold decreases, impact depth increases from360mm to500mm. When port angle increases from12°to15°, the impact depth increases from320mm to360mm. When port area ratio increases from2.48to2.97, temperature in top of the mold reduces2℃or5℃, temperature in bottom of the mold reduces3℃.It is known from the experimental results that7#SEN is the optimal one, and140mm or180mm is optimal submergence depth.