Study On Microstructure Uniformity Of 2205/NI/EH40 Clad Plate By Controlled Rolli Ng And Heat Treatment

In the process of plastic deformation of metal materials,due to the different degree of deformation at different positions,the internal structure of the material presents an uneven distribution,which seriously affects the formability of the sheet.The reasonable control of rolling process and heat treatment process can ensure the microstructure uniformity of the composite sheet to a certain extent.This paper takes 2205/NI/EH40 as the research object,in order to improve the overall uniformity of plate,combined with numerical simulation and experimental verification,to explore the influence of rolling process and heat treatment process on the microstructure uniformity of plate.The three-dimensional coupled hot rolling model of 2205/NI/EH40 clad plate was established by deform finite element software to explore the minimum reduction rate of2205/NI/EH40 duplex stainless steel clad plate bonding under different rolling processes.According to the criterion of interface adhesion in multi pass rolling process,the macro field at the interface position was analyzed,and the interface bonding condition of final rolled plate under the selected rolling temperature,rolling speed and other process parameters was explored.According to the flow stress curve of bimetal,the dynamic recrystallization model of material was established to explore the grain distribution in the thickness direction of2205/NI/EH40 duplex stainless steel clad plate under different rolling temperature,rolling speed and other rolling process parameters.The microstructure uniformity of grain under different rolling process parameters was determined by TOPSIS method considering the non-uniformity factor,average grain size and average rolling force.On the basis of finite element simulation,the multi pass hot rolling tests with three optimal rolling parameters were carried out on a two high mill.After the test,the samples were taken to observe the microstructure,and the microstructure evolution of each pass under the optimized process was analyzed to verify the numerical simulation results.With the help of universal material testing machine,the mechanical properties of the sheet after each pass rolling under the most optimized process were evaluated.According to the material characteristics of 2205 and EH40 at high temperature,three reasonable heat treatment processes are set by analyzing the CCT / TTT curve of the two materials under the premise of ensuring no harmful phase.Deform finite element simulation software was used to simulate the heat treatment process of 2205/NI/EH40 duplex stainless steel clad plate.The evolution of internal structure uniformity of each layer of material under different heat treatment processes was explored and verified with heat treatment test.Through the above research work,the rolling process to achieve more uniform microstructure of 2205/NI/EH40 duplex stainless steel clad plate was obtained.At the same time,through the heat treatment experiment,the uneven microstructure distribution of the rolled plate was further improved,which can provide reference for the preparation of duplex stainless steel clad plate.