Study On Bending Characteristics And Roller Leveling Process Of Bimetal Composite Plate

Bimetal composite plate is with excellent service performance and cost-effective.There is a wide range of market demand of high-quality large-size metal composite plate in the petroleum,chemical,marine engineering,shipbuilding and other industries.At present,the research on metal composite plate is guided by the actual demand and problems in production.But,the theoretical research and investment on the mechanical behavior of the material,such as the elastic-plastic deformation during the leveling process,is rare.There are differences in mechanical property between the different materials for each layer of the bimetal composite plate.The synergistic deformation of different layer during the bending process will significantly affect the mechanical behavior of the composite plate bending process,and its pre-treatment defect shape is more complex.The traditional leveling theory for the single material sheet cannot be applied directly to the analysis of leveling process of bimetal composite plate.In this paper,the method of theoretical analysis and numerical calculation is used to study the bending characteristics of bimetal composite plate and its roller leveling process.The main contents and main conclusions of the paper are:1)Based on the theory of engineering elastic-plastic mechanics,the simple bending process of bimetal composite plate was analyzed.and the judgment model of complex section elastic-plastic state evolution path of bimetal composite plate was established.The results show that the section of the bimetal composite plate will undergo five different elastic-plastic states,with different degrees of strain neutral layer migration,and the residual stress distribution is inclined to the weaker side.The reverse yield conditions and its influence during bimetal composite plate spring back process were obtained.2)The curvature integration model of the bimetal composite plate roller leveling process was established.The influence of bending history on the function of the mechanical parameters was considered.Combined with the bending characteristics of the bimetal composite plate section,the combination of analytic method and numerical method was used to complete the solution of model.Based on the model,the roller leveling process of the typical bimetal composite plate was analyzed.The results were compared with the single material plate.It is found that the mechanical parameters of the bimetal composite plate roller leveling process are much different from that of the single material plate.3)The leveling parameters of the bimetal composite plate with different initial parameters were studied.The results show that the effect of the adjustment of the tail roller on the quality on the plate is greater than the adjustment of the first roller.It will adversely affect the quality of plate after leveling when the section plastic deformation rate of the last elastic-plastic bending is not less than 40%.A new reduction process design method of the bimetal composite plate roller leveling process was put forward.The active control of residual stress and residual curvature of bimetal composite plate after leveling was realized.4)A curvature integration model for the accurate analysis of the complete leveling process of bimetal composite plates with complex shape defects was established.The influence of biting-in and tailing-out stages on leveling process was considered.The roller leveling process of a plate with stochastic curvature distribution along length direction was analyzed.The analytical results of two different curvature integration models were compared.The contact angles change along with leveling process and the curvature and stress distribution change along the length of plate were analyzed.It is found that the residual stress and the residual curvature are large at both ends of the plate,about 1?1.5 times of the length of roller space.5)The bimetal composite plate roller leveling experiment was conducted.And the experimental data of the mechanical behavior of the bimetal composite plate during the leveling process were obtained.The experimental data were compared with the theoretical analysis results.The curvature integration models were verified by the roller leveling experiment of bimetal composite plate with different initial single curvature and the roller leveling experiment of bimetal composite plate with uneven distribution of curvature in the longitudinal direction.