Study On The Technology Of Preparing Stainless Steel Clad Plate By Linear Friction Welding

Due to its superior performance and low price,stainless steel composite board can be used as a substitute for pure stainless steel and has good social benefits,as a solid joining method,linear friction welding technology can be used to join regular-shaped workpieces,it can also be used to weld parts with complex geometric shapes.It has a series of advantages such as fast processing speed and low cost,and is widely used in the aviation industry.In this paper,a set of equipment for preparing stainless steel clad plates by linear friction welding is designed by itself.The stainless steel clad slabs are prepared with Q235 steel and SUS304 stainless steel as raw materials,and the stainless steel clad billets are rolled;the interface microstructure and morphology of the samples after welding and rolling were observed with a metallurgical microscope and a scanning electron microscope,the evolution law of the interface structure of the composite slab during friction welding and rolling was studied,the influence of process parameters on the interface structure was analyzed,the interface was detected by X-ray energy spectrum,and the diffusion law of elements was studied.The results show that in the process of linear friction welding,due to the influence of uneven metal surface topography,uneven pressure distribution and elastic deformation,the stainless steel and carbon steel are locally welded.The results of rolling the stainless steel clad billet show that there is no rolling crack at the interface during the rolling process,the bonding strength of the composite plate interface reached 392 MPa,indicating that the linear friction welding technology can be used for the production of stainless steel composite slabs.During the friction welding process,stainless steel and carbon steel produce high-speed friction shear stress and strain effects at the composite interface,this causes the interface to heat up rapidly and causes dynamic recrystallization of the interface metal.From the composite interface to the carbon steel matrix side,the temperature gradually decreases,the stress intensity gradually decreases,and the grain refinement gradually weakens.At the same welding frequency,with the increase of welding pressure,the range of the fine grain area at the interface increases,and the grain refinement effect is more obvious.The content of Ni in the fine-grain zone and the heat+deformation affected zone is higher than that of the carbon steel matrix,indicating that alloying elements diffuse from the stainless steel side to the carbon steel side.After hot rolling,there is still a mixed melting zone in the welding compound zone.Outside the mixed melting zone is the rolled ferrite plus pearlite structure.With the increase of rolling passes,the width of the mixed melting zone gradually decreases.The carbon steel structure is gradually refined.Under the action of high temperature and rolling pressure,metallurgical recombination occurs in the unwelded area,and the interface recombination is good.After four passes of rolling,the shear strength of the interface reaches 380 MPa.Decarburization occurs on the carbon steel side of the composite interface,and a carbon diffusion layer appears on the stainless steel side,with M₂₃C₆carbides in the layer.With the increase of rolling passes,the width of the decarburization layer and diffusion layer gradually decreases.