Study On Microstructure And Mechanical Properties Of The Interface Of Vaccuum Hot Rolled 316L/EH40 Composite Plate

EH40 low alloy steel has the characteristics of high strength,high toughness,low cost,316 L stainless steel has excellent corrosion resistance,but the price is relatively high.316L/EH40 composite plate has excellent comprehensive properties,and can be used as the ship’s steel for polar navigation,which can not only adapt to the polar Marine environment,but also can greatly reduce the cost.In this paper,the microstructure and properties of 316L/EH40 stainless steel composite plate under different rolling processes were studied,the influence of rolling process parameters on microstructure evolution of sheet metal was analyzed,the tensile strength of stainless steel composite specimen was measured under selected process parameters,and the influence of interlayer on the diffusion of elements was studied.Based on MARC finite element simulation software,the finite element model of hot rolling composite was established,and the hot rolling process of 316L/EH40 stainless steel composite slab was simulated.The hot rolling process of different friction coefficient,reduction rate and rolling temperature was simulated.The distribution of stress-strain and residual stress along the thickness direction under different processes was analyzed,and the composite quality of the composite plate was evaluated.The simulation results provide a reference for the design of subsequent experiments and the selection of process parameters.The vacuum hot rolling process of 316L/EH40 stainless steel clad plate was simulated by Gleeble-3800 hot compression machine.The composite specimens with different roughness,rolling reduction rate and rolling temperature were obtained.The experimental schemes of microhardness test,metallographic structure observation and energy spectrum analysis are given.Aiming at the skewness of composite specimens in compression,the causes of skewness are found by means of finite element trial and error method,and the solutions are put forward.The relationship between decarburization layer thickness near the interface and experimental variables was analyzed by metallographic microscope;the relationship between inclusion content near the interface and experimental variables was analyzed by scanning electron microscopy;the relationship between diffusion distance of Cr element near the interface and experimental variables was analyzed by energy dispersive spectrometer;and the relationship between hardness value near the interface and experimental variables was analyzed by microhardness tester.A set of rolling parameters were obtained by analyzing the experimental results.The Gleeble-3800 thermal simulation test machine was used to prepare composite specimens with specific process parameters.The mechanical properties of composite specimens were tested by tensile test,the rationality of rolling process parameters was verified,and the fracture of the tensile specimens was analyzed.The effect of intermediate interlayer on hindering element diffusion was analyzed by adding interlayer between the base and the cladding layer.The effect of interlayer on mechanical properties was obtained by tensile test.Through the above research work,a set of reasonable rolling process parameters were finally obtained,which can provide certain reference for rolling 316L/EH40 stainless steel composite plate.