| The continuous casting mold is one of the core components of the continuous casting equipment,and its normal operation directly affects the production efficiency of the continuous casting machine and the quality of the slab.However,in actual production process,due to various internal and external factors,the crystallizer can not vibrate according to the set ideal vibration curve,resulting in abnormal vibration state.For example,the mold rotates in the up and down displacement direction and swings in the front and back displacement direction.This abnormal vibration state will have varying degrees of impact on the slab solidification,heat transfer and stress during deformation,and may cause defects such as vibration marks and cracks on the slab surface,in severe cases May cause rupture.The thermal and mechanical properties of the billet in the mold have an important influence on the continuous casting process.In recent years,the study of the heat transfer law of the mold is of trans-epochal significance for improving the productivity of continuous casting and the surface quality of the cast slab.Due to the complexity of solidification and heat transfer of molten steel in dies,it is difficult to conduct industrial tests to understand the internal conditions of the cast slab.Therefore,the use of numerical simulation to study the heat transfer law of the mold is an effective method.In this paper,a mold with a cross section of 1600mm×67mm in a slab factory is the research object.Based on theoretical calculations,starting from the temperature field and stress field of the slab,the mold,slab and cooling are established using software such as ANSYS and Solid Works.The finite element model of the grid assembly,through calculation and simulation,obtains the vibration characteristics and abnormal vibration behavior information of the mold.According to the simulation results,the stress field of the slab is analyzed,and the influence of abnormal vibration on the stress and deformation of the slab is obtained.In order to further analyze the stress and deformation of the casting billet in the mold by the abnormal vibration,the vibration characteristics of the mold under different drawing speeds were studied by the controlled variable method.It can be obtained that the movement curve of the mold vibrating table at high-speed drawing deviates from the sinusoidal curve.,This will cause the mold to move unevenly and break out and other failures.Therefore,during the overhaul and maintenance of the mold vibration table,it is necessary to find out the reason and influence degree of the deviation of the movement curve of the mold vibration table to ensure the performance of the mold vibration table.By simulating the abnormal vibration process of the mold,the obtained stress field simulation results show that when the vertical displacement vibration is abnormal,there are four stress concentration positions in the casting slab,which are the corner of the cooling grid and the corner of the casting slab exit.As the drawing speed increases,the equivalent stress increases.The change rule of equivalent strain is the same.When the front and rear displacement swing is abnormal,the change rule is the same as that under the abnormal vertical displacement vibration condition,but the magnitude of the increase is smaller than the abnormal vertical displacement vibration condition.When the upper and lower displacement vibrations are combined with the abnormal vibration,the equivalent stress and deformation of the casting slab are the same as those under the sole action of the upper and lower displacement vibrations.The difference is that the stress and strain values of the former are increased.Therefore,when the front and rear displacement swing is abnormal,the increase in the billet drawing speed has less influence on the equivalent stress and deformation of the casting slab than the abnormal vertical and horizontal displacement vibration of the mold. |
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