Investigation On The Deformation Law Of Shell In The Foot Roll Area Of Large Slab Continuous Casting Mould

In the continuous casting process,the mold plays a vital role in maintaining the normal production of continuous casting and ensuring the quality of the slab.The bulging deformation of the billet shell in the foot roll area of the mold will increase the extrusion force between the casting billet and the mold,and increase the frictional force on the lower mouth of the mold copper plate,thereby aggravating the wear of the mold copper plate.The service life of the mold is shortened,and the excessive bulging deformation will also lead to a steel breakout accident.It is of great significance to study the deformation law of the billet shell in the foot roll area of the mold and propose a method to restrain the deformation of the billet shell.Firstly,the research on the solidification heat transfer process of continuous casting slab in the mold and the secondary cooling zone is carried out,and the heat transfer equation,boundary conditions and physical parameters required for the simulation of slab temperature field are determined,and the finite limit of slab solidification heat transfer is established.The finite element software ANSYS is used to simulate the model,and the temperature field distribution of the slab and the appearance of the solidified shell are obtained,and the effect of the process parameters on the center temperature of the wide face,the thickness of the shell and the position of the solidification end point is analyzed.influence,which provides the basis for the establishment of the bulging belly model of the blank shell.The three-dimensional shell bulging finite element model of the mold foot roll area under the action of the conventional foot roll is established,and the simulation is carried out to obtain the bulging deformation law of the shell shell and the variation law of the bulging equivalent stress.The results are compared,and the two are basically consistent,and the influence of changing the distance between the mold and the foot roll area or the pulling speed on the deformation law of the shell bulging is analyzed.Compared with the central part of the conventional cylindrical foot roll,a specialshaped foot roll is proposed,and the size of the central protruding part of the specialshaped foot roll is adjusted to simulate the bulging deformation of the three-dimensional shell of the mold foot roll area for many times.,the bulging deformation of the billet shell and the contact stress between the lower mouth of the mold copper plate and the casting billet under the action of different-sized special-shaped foot rolls were obtained.The results show that the size of the central protruding part of the special-shaped foot roll is within the adjustable range,the bulging deformation of the billet shell and the contact stress between the lower mouth of the mold copper plate and the casting billet gradually decrease with the increase of the protruding size,and the mold The frictional force on the lower mouth of the copper plate is also reduced accordingly.Comparing the simulation results with the theoretical analysis results,the simulation results are basically consistent with the theoretical analysis results.It is proved that the special-shaped foot roller can reduce the bulging deformation of the billet shell and the extrusion force between the casting billet and the mold,and the wear of the lower mouth of the copper plate of the mold is correspondingly weakened,thereby improving the service life of the mold.