Four-high Mill Cold Rolling Strip Material Flatness Problem Of The Numerical Simulation

The profile of strip is one of important factor that affect the quality and ratio of finished product of strip. Many researchers attached importance to it. The cold rolling is the complicated process that includes geometry non-linearity, material non-linearity and contact non-linearity. The profile of strip is the problem that researches the uniformity of strip portrait.In the paper: the correlative foundation knowledge of profile is narrated, the foundation theory of elastoplasticity finite element system is introduced, the solution process of big elastoplasticity finite element method is deduced. These works provides theory foundation for the research of the paper.The four rollers rolling mill is basal model in the paper, elastoplasticity finite element method is used to simulate the cold rolling process. The fact rolling process is seriously analyzed, correct elastoplasticity finite element model is founded. It includes to make sure of the reasonable boundary and original condition, to choose correct material stress-strain relation,yield criterion and the sort of element , to ensure the rationality of mesh . Two aspects of effect factors of profile is emphatically studied in the paper: the elasticity deformation of work roll and three dimensions plastic deformation of metal .The first, the elasticity deformation of roller is simulated by using finite element analysis software. erecting finite element analysis model,applying Matlab to program to calculate the rolling power and estimating the contact area between work and back roll is included to this part; diameter ratio of work and back roll,length of back roll,width of strip,bending force of work roll and rolling force affecting the elasticity deformation of work roll is researched. The second, elastoplasticity finite element method is used to simulate the dynamic process of rolling. In this part, the sorts of effect factors of profile is analyzed in the paper; width of strip,rolling reduction ratio and bending force of work roll affecting of profile and three dimensions plastic deformation of metal is researched. Besides upwards aspects, the paper contrasted the analysis results of rigidity roller and elasticity roller to proof the analysis result of elasticity roller rolling process to be true.By the detailed analysis, the paper gained the rules that the sorts of factors affecting elasticity deformation of roller and three dimensions plastic deformation of metal. Those rules can guide physical experiments and fact manufacture. The results of the paper accelerate the application of using finite element method to resolve the problem of profile.