Numerical Simulation On Heat Transfer And Stress In Stainless Steel Slab Continuous Casting Process And Soft Reduction

In this paper,a 1Cr13 stainless steel slab in a continuous casting process in a steelmaking plant is taken as the research object.The basic parameters of the slab caster,and the thermophysical properties parameters and high temperature mechanical properties parameters of the steel are used in the numerical simulation by using the commercial software ABAQUS.A two-dimensional solidification heat transfer model and a elastic-plastic thermal stress coupling model are established to simulate the temperature field and stress field in the slab in the continuous casting process and the soft reduction process.The nonlinear variation of the thermophysical properties parameters and the high temperature mechanical properties parameters of the steel with respect to temperature are taken into account in the solidification heat transfer model and thermal stress coupling model.The corresponding thermal boundary conditions,displacement boundary conditions are determined.In order to simplify the model reasonably,a two-dimensional slice method is adopted,and the half section is selected to simulate considering the symmetry of the slab cross section.Based on the solidification heat transfer model,the influence of the process parameters such as different casting speeds and cooling intensities on the temperature distribution in the 1Crl3 stainless steel slab is analyzed.Based on these results,the influence of thecorresponding parameters on the stress distribution in the 1Cr13 stainless steel slab is analyzed by the thermo mechanical coupling model,and the influence of the different reduction schemes on the stress distribution 1Cr13 stainless steel slab is also compared.The results are as follows:(1)The influence of casting speed on slab temperature and stress variation:The casting speed has a great influence on the solidification process of the 1Cr13 stainless steel slab.With the increase of casting speed from 0.8m/min to 1.2m/min,the stainless steel slab cooling times are constantly shortened and cooling intensity are decreasing,the surface temperature of slab increases and liquid core length increases,the shell thickness becomes thinner and the surface thermal stress of slab decreases.As for an 0.2m/s increase of casting speed,the surface temperature of the exit slab increases about 35℃ and the thermal stress is reduced by about 15%,the point of completely solidification moves back about 5m form slab.(2)The influence of cooling water quantity on slab temperature and stress variation:The cooling water quantity has obvious effect on the temperature of the wide surface center and corner of the of the slab.With the increase of cooling water quantity from 80%to 120%,the cooling intensity is increasing and the surface temperature of slab decreases,the solidification shrinkage increases and the surface thermal stress increases.With 20%increase in cooling water quantity,the surface temperature at the exit of slab caster decreases about 20℃and the thermal stress increases about 22%,the solidification end point moves forward about 1.5m for slab.(3)Stress distribution of the casting slab in reduction process under different cooling water quantity and casting speed:Under different cooling water quantity and casting speed,the numerical simulation is carried out for the slab reduction section,select the stress value of characteristic point to compare with the critical stress value,The results show that the value of thermal stress are less than the critical value.That is to say,under the continuous casting process and reduction process parameters in this paper,it can increase the speed of casting and reduce the amount of cooling water properly to improve the quality of slab.(4)The influence of different reduction amount and position on the stress of the slab in the reduction section:The initial reduction increases under the same reduction in the reduction section,that is press the position forward,the stress at the characteristic points of slab increases.The change of corner stress are obvious,with the increase of initial reduction by 5 times it increases by 25%,the stress changes of other feature points are relatively small.Therefore,under the same reduction in the reduction section,adopt larger reduction for slab,it can be realized by reduction position moving back,moreover it can reduce the risk of slab crack.