Study On The Effect Of Abnormal Oscillation Of Mould On Slab Stress

In the steel production industry,continuous casting technology plays a key role.Continuous casting technology is a process in which molten steel is continuously cast and cooled into a set shape and size by a series of cooling devices.As a very important part of the continuous casting machine,the crystallizer works efficiently and smoothly,which will effectively guarantee the production efficiency and product quality of steel.However,in the actual production process of continuous casting,due to various factors,the crystallizer will not vibrate according to the ideal set vibration curve and then generate various abnormal vibration conditions,such as the crystallizer rotates in the up and down direction.The direction is swung and so on.This anomaly will have different degrees of stress effects on the continuous casting billet during the solidification forming process,and may cause defects such as vibration marks and cracks on the surface of the continuous casting billet.Based on the production data of a thin steel plate mill,this paper analyzes the influence of the abnormality of the crystallizer vibration on the slab stress by using the data processing software MATLAB and the finite element software ANSYS.The research of this subject can be divided into the following contents:1.Using the displacement sensor to measure the up and down displacement and the front and rear swing displacement data of the mold on the production site,and post-processing the data through the software MTALB.Combining the processed data with the mold drawing provided by the factory and the relative position of the sensor installation,the kinematics analysis is performed on different working conditions of the crystal oscillator vibration abnormality,and the crystallizer motion equation is established.2.In view of the complex temperature of the slab in the mold,and its mechanical properties are affected by the high temperature,it is necessary to obtain the temperature change of the slab during the heat transfer process in the mold.The two-dimensional unsteady heat transfer model of the slab was established by the finite element software ANSYS.Based on the heat transfer characteristics of the node temperature and the layer-by-layer transfer,the ANSYS command flow APDL technology was used to transform the two-dimensional unsteady temperature field of the slab into Athree-dimensional steady-state temperature field is applied as a body load to establish a three-dimensional mechanical model.3.For the continuous casting billet under different working conditions of crystallizer vibration,the motion of the crystallizer is applied as the relative constraint on the continuous casting billet.The three-dimensional elastoplastic mechanical model of the continuous casting billet is simulated by ANSYS under different working conditions.,analysis of the stress distribution of continuous casting billet.According to the field data and simulation results,the crystallizer has a pressing effect on the continuous casting billet under the condition of up and down displacement of the crystallizer.The surface layer of the narrow surface of the continuous casting billet is subjected to large force,which is affected by the relative displacement and rotation of the crystallizer.It increases with the increase of relative rotational angular displacement;the oscillating condition of the crystallizer is divided into three kinds of oscillating waveforms:triangular,trapezoidal,multi-peak and valley,and the stress is large under the triangular and multi-peak valley conditions(maximum value 120MPa),mainly concentrated in the wide-face distance meniscus 0.6~0.7m,in the actual continuous casting site process,should reduce the triangle swing and multi-peak peak-shaped swing as much as possible.Based on the consideration of the influence of thermal properties of materials,this paper proposes a simulation method for simulating the stress field of slab during the abnormal vibration process of the crystallizer,and obtains the simulation results.In order to explore the theoretical reference of the surface quality of continuous casting billet.