| The clad plate with low alloy steel EH40 as the base and stainless steel 316 L as the cladding has certain mechanical strength and corrosion resistance.In the process of producing stainless steel composite plates by the vacuum hot rolling method,it is often necessary to add a metal interlayer to block the diffusion of elements between the interfaces.Because the sample processing is complicated,the air tightness needs to be checked after welding and packaging,and the interface vacuum is not easy to guarantee,resulting in a certain degree of oxides and impurities.In order to ensure the interface bonding strength and improve the purity,the purpose of this paper is to improve the interlayer vacuum of stainless steel composite plates with intermediate.Starting from the introduction of intermediate materials,the effects of the method of preparing intermediate from molten metal on the interfacial characteristics and bonding strength of clad plates are studied.Based on the method of adding molten interlayer,the Fe-Co-Ni alloy with good fluidity was selected as interlayer material.Compression forming test was carried out on the composite with Fe-Co-Ni intercalation,the diffusion of elements near the forming interface was observed,the barrier property of Fe-Co-Ni intercalation was investigated,the method of filling interlayer in 316L/EH40 composite billet by pressure difference under vacuum environment was put forward,and the mathematical model of molten Fe-Co-Ni flow was established from the point of view to describe the coating process of the melt.The model of 316L/EH40 clad plate with intermediate filling flow is established by ProCAST finite element software.Numerical simulation study of process parameters such as intermediate thickness,melt temperature and filling pressure difference that affect the quality of the intermediate.The influence of different process parameters on melt flow characteristics is investigated.Formulate process parameter optimization charts based on the coating coverage rate,select parameters from the complete coating coverage area,conduct simulation studies on melt solidification characteristics and shrinkage cavity distribution,and determine the influence weight of coating process parameters.The melt temperature,the thickness of the intermediate and the filling pressure difference,which have a greater impact on the quality of the intermediate molding,are designed using orthogonal test methods to design the intermediate filling simulation scheme.The shrinkage rate is the evaluation index.According to the simulation results,a set of filling process parameters are selected that can ensure the filling rate and the intermediate has no macro shrinkage.The filling test of intermediate is finished.Comparing the coating rate of the intermediate and the formation of shrinkage with the results of numerical simulation.The phase transition of the base multi-layer sheet is analyzed.The two-roll mill of five-pass hot rolling test on molten intermediate filled and welded blanks.Analysis of forming interface characteristics and mechanical properties by scanning electron microscope and material tensile testing.The influence of intermediate molding quality on interfacial oxides and mechanical properties.The formation of interfacial oxides and inclusions in the two methods of adding intermediate blanks is compared,and the influence of the intermediate method for preparing molten metal on interfacial properties is obtained.Through the above research work,a set of intermediate filling process parameters with high coverage and no macro shrinkage defects are obtained.Finally the 316L/EH40 clad plate with high interface purity and good bonding strength is obtained.It can provide a reference for the development of stainless steel clad plates with good performance and high purity. |
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