Research On Interfacial Microstructure And Properties Of Stainless Steel Clad Plate Fabricated By Hot Rolling

The stainless clad plate possesses both corrosion resistance of stainless steel cladding and excellent mechanical properties of carbon steel substrate.Therefore,the stainless clad plate is widely used in major equipment industries such as petrochemical engineering,maritime engineering,oil and gas pipelines etc.In this paper,the interfacial microstructure and mechanical properties of stainless steel clad plate which is combined by stainless steel?304?and carbon steel?Q235?are systematically studied in order to meet its requirements for carrying service and plastic processing.Moreover,the fracture mechanism and interface toughening mechanism of stainless steel clad plate are revealed.The stainless steel clad plate is fabricated by symmetry assemble technology and vacuum hot rolling at three different bonding temperatures.The interfacial microstructure and alloy elements diffusion behavior of stainless steel clad plate are systematically researched.Moreover,the interfacial microstructure evolution is analyzed.The results show that forming ferrite structure of the decarburized layer and corrosion easily carburized layer due to the diffusion behavior of carbon,and showing the typical uplift diffusion phenomenon due to the highest concentration of carbon at the interface.Moreover,a large amount of chromium carbides are produced at the grain boundary of the carburized layer,and decrease its corrosion resistance.In addition,the stainless steel clad plate forms a true interface layer of 300 to 400 nm and distributes a large amount of Si-Mn oxide and Cr₂₃C₆.Hardness test results show that from the substrate to the interface decrease first and increase after,from the interface to the cladding increase first,decrease after and finally tends to be stable.With the increase of hot rolling temperature,the interfacial shear strength is increasing gradually.Moreover,the shear fracture occurs at the interface by 1100^oC,but the shear fracture occurs at the decarburized layer by 1200^oC.Metallurgical bond of stainless steel clad plate at the bonding temperature of 1300^oC is the highest due to the diffusion of alloy elements more fully.The tensile test results show that the strength of the stainless steel clad plate decrease gradually with the increase of the hot rolling temperature,which is due to the gradual increase of the grain size.However,the elongation increases gradually,which is due to the softening of the base.The stainless steel clad plate by the lower temperature produce serious delamination fracture,which can't prevent carbon steel early necking.However,the stainless steel clad plate by the higher temperature can prevent the delamination fracture and early necking,so that the substrate and cladding deformation coordination,resulting in a higher uniform elongation.