Modeling And Analysis Of Thickness And Strain After Rolling For The Two-Layered Metal Clad Plate Produced By Snake Rolling

Metal clad plate rapidly occupied the market on the basis of its good performance and significant social and economic benefits.However,there are still some technical problems restricting the improvement of clad plate quality and production efficiency.Suitable thickness ratio and sufficient rolling deformation are the key factors to determine the properties and quality of metal clad plate.At present,the thickness ratio of the plate before rolling cladding is still set by manual trial and error.And the clad plate needs to be tested for many times and qualified before mass production,which will greatly reduce the production efficiency;The deformation of clad plate is not uniformly transferred along the thickness direction in the rolling cladding process,there is a lack of accurate mechanism model to analyze the deformation process.Therefore,it is of great significance to establish the mathematical models of thickness and equivalent strain after rolling for clad plate production.In this thesis,the mathematical models of the thickness and the equivalent strain of the double-layer metal clad plate after rolling are established by using the stream function method and the upper bound method.The effects of different process parameters on the deformation behavior of rolling cladding were analyzed.The accuracy of the mathematical model was verified.The main work of this thesis is as follows:(1)Reasonable assumptions are made for the cladding process based on the deformation characteristics of asymmetrical rolling with the same roll diameter and different roll speeds.The boundary functions are solved according to the geometric relation in the fixed coordinate system.The stream functions of metal plastic deformation in the deformation zone are established according to the boundary functions.The kinematic allowable velocity field is obtained by taking the partial derivative of the stream function.Then the strain rate component is obtained by taking the partial derivation of the velocity field.The total power is obtained by integrating the strain rate component.Based on the upper bound theory,Fminsearch algorithm in Matlab toolbox is used to optimize the total power,and the nearly real thickness value of clad plate after rolling is obtained.Based on the kinematic allowable velocity field,the equivalent strain mathematical model of asymmetrical rolling cladding is established according to the definition of strain;(2)The characteristics of snake rolling cladding and its difference with asymmetrical rolling cladding are analyzed and new assumptions are made based on the mathematical model of asymmetrical rolling cladding.Similar to the analytical process of asymmetrical rolling cladding,the stream function,the kinematic allowable velocity field,the strain rate field and the total power in the deformation zone of snake rolling cladding are solved according to the new boundary functions.Finally,the thickness value of the clad plate after rolling by snake rolling cladding was obtained according to the upper bound theory.Based on the kinematic allowable velocity field,the equivalent strain mathematical model of snake rolling cladding is established according to the definition of strain;(3)Compared with symmetric rolling cladding under the same process,the shear strain of snake rolling cladding is increased by 18.9%,the equivalent strain of snake rolling cladding is increased by 3.76%,the bending curvature of clad plate by snake rolling cladding is decreased by 28.6%,and the grain at the bonding surface is finer.The influence law of process parameters on the thickness ratio and equivalent strain after rolling was analyzed by finite element simulation and experiment,and the established mathematical model was verified.The maximum relative error of the thickness of clad plate after rolling mathematical model was determined to be ≤ 5.99%.The maximum relative error of the equivalent strain mathematical model was determined to be ≤ 12.61%.The mathematical model has high accuracy.