Numerical Simulation Of Effect Of Carbon Content On Heat Transfer And Stress In Steel Slab Continuous Casting Process And Soft Reduction

In order to solving slab surface and internal quality problems of 65Mn steel and Q345C steel produced in a domestic steel plant,in this paper,a finite element analysis software ABAQUS is used to establish a heat transfer and thermal stress coupling model in a 1250mmx230mm slab continuous casting and soft reduction process.The corresponding thermal boundary conditions,displacement boundary conditions,high temperature thermal/mechanical properties are determined.Through different numerical simulation cases(different casting speeds,cooling intensities and initial reductions)that considering the nonlinear parameters of high temperature thermal/mechanical properties,combined with previous research results on 55C steel,the effects of different carbon contents on the temperature field and the stress field in the slab continuous casting process and soft reduction process are compared and summarized.And on the basis of this,secondary cooling water distribution optimization and soft reduction optimization are carried out.The main results are as follows:(1)The effect of carbon content on the slab temperature and stress in different casting speeds:with the increase of carbon content of steel,both temperature difference and stress difference caused by the increase of casting speed gradually decrease at corresponding feature point of slab.The effect of casting speed on the displacement of 65Mn slab solidification end point is larger than that of the Q345C.(2)The effect of carbon content on the slab temperature and stress with different secondary cooling water:with the increase of carbon content of steel,both temperature difference and stress difference of slab caused by the decrease of secondary cooling water in second cooling zone ? to zone? gradually decrease at corresponding feature point.The effect of secondary cooling water on the displacement of the 65Mn slab solidification end point is larger than that of the Q345C.The effect of carbon content on the optimal secondary cooling water:with the increase of carbon content,the overall change trend of the optimal secondary cooling water first increases and then decreases,but the overall optimal secondary cooling water quantity of high carbon steel is higher than that of low carbon steel.(3)The relationship between the stress and the critical stress of the casting slab in soft reduction process under different process parameters:with the increase of casting speed or the decrease of secondary cooling water,the stress at the steel slab feature points in soft reduction process are all less than the critical stress.It is indicated that proper increase of the casting speed and the optimal secondary cooling water can further reduce the possibility of cracking in the slab continuous casting process.(4)The effect of initial reduction on the stress of the slab in the soft reduction process:with the initial reduction decreased,the stress at the feature points at corresponding position of the slab decreases.When the initial reduction decreased 15%,the maximum stress of the 65Mn slab at the exit of reduction section is 22.8%lower than that in the original reduction,and the stress of Q345C slab at the exit of reduction section is lower by 4.5%.