Study On Preparation And Mechanical Properties Of 2Cr13/316L Multilayered Stainless Steel Composite Plate

With the rapid development of industry,the performance of a single material has been difficult to meet its diverse needs in complex environments.Because 2Cr13 martensitic stainless steel has high strength but poor plasticity,while 316 L austenitic stainless steel has good plasticity but low strength,the 2Cr13/316 L multi-layered stainless steel composite plate composed of 2Cr13 and 316 L has high strength,good plasticity and corrosion resistance,providing a new idea for the development of marine engineering materials.Due to the complexity of its preparation process,the diversity of rolling factors and the importance of the subsequent heat treatment process,the preparation and interface bonding of 2Cr13/316 L multilayered stainless steel composite plate are difficult to accurately control.In order to improve the interfacial bonding strength of 2Cr13/316 L multi-layered stainless steel composite plate,improve its comprehensive mechanical properties and reveal its interfacial bonding mechanism,this paper systematically studied the microstructure,mechanical properties and interfacial behavior of 2Cr13/316 L multi-layered stainless steel composite plate from the perspectives of rolling process and heat treatment process.Twelve groups of multi-layered stainless steel composite plates were prepared by changing the four rolling process parameters of material,rolling temperature,rolling reduction and cooling method after rolling.The analysis results showed that the microstructure of 2Cr13 layer in 2Cr13/316 L multi-layered stainless steel composite plate is martensite + ferrite,and that of 316 L layer is austenite.Under rolling condition,the microstructure of 2Cr13/316 L multilayered stainless steel composite plate is elongated rolling texture.When other rolling conditions are constant,the tensile strength and elongation of 2Cr13/316 L multi-layered stainless steel composite plate were located between the full 2Cr13 multi-layered stainless steel plate and the full 316 L multi-layered stainless steel plate.With the increase of rolling temperature,the strength of 2Cr13/316 L multi-layered stainless steel composite plate decreased and its plasticity increased,which was directly related to the increase of ferrite content in 2Cr13 layer and the recovery and recrystallization of grains at the higher temperature.With the increase of rolling reduction,deformation resistance and strength increased,but excessive rolling reduction led to break phenomenon in the composite plate,which reduced its strength.The cooling method after rolling had little effect on the properties of 2Cr13/316 L multi-layered stainless steel composite plate.In summary,the best rolling process of 2Cr13/316 L multilayered stainless steel composite plate was 1130 ?,82% and wind cooling.The tensile strength and elongation were 1205 MPa and 18.3%,and bending strength was 3687 MPa,which exhibited the best comprehensive performance.The 2Cr13/316 L multi-layered stainless steel composite plate with the best rolling process performance was used to explore the subsequent heat treatment process.By changing the heating temperature and holding time,the microstructure and mechanical properties of 2Cr13/316 L multi-layered stainless steel composite plate after heat treatment were compared and analyzed.It was found that the microstructure of each layer did not changed after heat treatment,and the grains were equiaxed due to recovery and recrystallization.The best heat treatment process was quenching after 950? for 5min.The tensile strength and elongation were 1012 MPa and 21.5%,and bending strength was 2856 MPa.After heat treatment,the change of elements at the interface was relatively smooth.The diffusion distance increased from 1.8?m to 10?m,and the shear strength increased from 420 MPa to 445 MPa,which indicated that the heat treatment process promoted the diffusion of elements.In-situ tensile results also showed that the interface of 2Cr13/316 L multi-layered stainless steel composite plate played roles in load-bearing and load-transferring,and there was good deformation coordination among the layers without delamination after heat treatment.This showed that heat treatment process can improve the interfacial bonding strength and comprehensive performance of 2Cr13/316 L multilayered stainless steel composite plate.The results of laser confocal,electron backscatter diffraction and transmission showed that heterogeneous common grains were formed at the interface of 2Cr13/316 L multi-layered stainless steel composite plate due to recrystallization.The heterogeneous common grains were composed of martensite and austenite.TEM analysis results showed that atomic diffusion occurred at the interface of heterogeneous common grains,forming a transition layer with a certain thickness.The interfacial bonding mechanisms were diffusion bonding mechanism and recrystallization bonding mechanism.