Study On Symmetrical Hot Rolling Forming And Heat Treatment Process Of 316L/Ni/EH40 Stainless Steel Clad Plate

Interlayer interface quality is the key to determine the overall performance of layered metal composites.Aiming at the problem that the interface properties of 316L/EH40 stainless steel composite plate are weakened due to element diffusion during hot rolling forming,adding an appropriate thickness of interlayer during the assembly process is used.The quality of the bonding interface is improved by effectively blocking the diffusion of elements between two layers of metal.High-purity nickel is selected as the sandwich material,and the 316L/Ni/EH40 stainless steel is selected as the research object.The influences of vacuum hot-rolled forming process and post-rolling heat treatment process on the forming quality of the composite plate are mainly investigated.Based on the unique advantages of the Gleeble-3800 thermal simulation testing machine in the field of material forming process research,the rolling experiment is simulated with the hot compression experiment of multi-layer composite samples with small cylindrical samples.The elements diffusion law of the interface position is explored by the hot compression test of 316L/EH40 composite sample,and the feasibility of nickel as an interlayer is analyzed.According to the hot compression test of 316L/Ni/EH40 composite samples,the influence law of nickel interlayers with different thicknesses on the interface bonding properties of composite samples is studied.Considering the characteristics of different simulation tasks,MSC.Marc finite element software is used to establish different three-dimensional thermos-mechanical coupling models of 316L/Ni/EH40 stainless steel composite hot-rolled forming.Based on the reasonable selection of interface bonding criteria,the effects of rolling reduction and pass distribution on the interface bonding of 316L/Ni/EH40 stainless composite plates are simulated and analyzed,the rolling force distribution and the plate residual stress distribution during five-pass hot rolling are predicted.Based on finite element simulation,the rolling process specification is formulated.Five-pass hot rolling test of 316L/Ni/EH40 stainless steel composite plate is used with a two-roll mill.After that,samples are obtained from the stainless steel composite plate.The influence law of cumulative reduction on the microstructure,the hole distribution,the microhardness,and the bonding strength of the composite plate interface.The performance of the five-pass final rolled sheet is evaluated through the tensile property test and the interfacial element spectrum test.Aiming at the structural characteristics of the 316L/Ni/EH40 stainless steel composite plate,in the case of ensuring that no serious element diffusion occurs at the interface,heat treatment goals are mainly researched like changing grassroots organizational structure,the refinement of structure grain,removing interface residual stress.According to this goal and component material characteristics,three heat treatment processes are formulated.The five-pass final-rolled sheet is used to carry out heat treatment test research,and the microstructure of the composite plate under different processes is explained in detail.The problem of interface quality degradation caused by the diffusion of harmful elements at the 316L/EH40 stainless steel composite plate’s interface is effectively solved.The beneficial exploration of the forming process and heat treatment process for the 316L/Ni/EH40 composite plate is carried out,which will provide a reference for the preparation of the heterogeneous metal composite plate.