Heat-resistant Surface Design And Simulation Optimization On 6061 Alloy Thin-walled Cylinder

The thin-walled cylinder of an equipment component requires excellent corrosion resistance,good mechanical properties and instantaneous high temperature resistance.The commonly used materials are steel and copper.Redesigning the material of the thin-walled cylinder into aluminum alloy can greatly improve the transportation efficiency of the equipment.The application demands are essential and urgent.Compared with steel,copper and other materials,the corrosion resistance,heat resistance and mechanical properties of aluminum alloy itself are insufficient.Taking6061 aluminum alloy thin-walled cylinder as the research object,this paper designs the surface layer of thin-walled cylinder on the basis of determining the initial conditions of gas heat flux and pressure in the cylinder under the service condition,and reveals some new phenomena and rules by simulating and analyzing the temperature field and stress field of thin-walled cylinder,adjusts and optimizes the structure of thin-walled cylinder,reduces the stress concentration,and gives some suggestions.Suggestions for the design and application of the surface layer are given,and the effect of anodic oxidation on the corrosion resistance of the cylinder wall is also studied.The main research work and results are as follows:?1?When the heat flux of the inner surface of the aluminum alloy cylinder is constant,the temperature of the thin wall area rises rapidly.The thin wall of the front end of the cylinder connected with other components can reach 350?.At this temperature,recrystallization of aluminum alloy may occur,resulting in the decrease of hardness and the risk of cracking or even fracture.?2?The stress concentration of the front oblique shoulder corner and the right angle structure at the bottom of the thin-walled cylinder is optimized to be a round corner structure,and the stress decreases from 600 MPa and 1350 MPa to 80MPa and810 MPa,respectively.The effect of stress concentration decrease is remarkable.?3?TiN,TiC and Al₂O₃ coatings can significantly improve the heat resistance of6061 aluminum alloy thin-walled cylinder.The Al₂O₃ coating can reduce the temperature rise of the cylinder wall by 25?,and the technology of preparing alumina coating by anodic oxidation is mature,which can be used for thin-walled cylinders for general purposes.Titanium nitride and titanium carbide coatings can reduce the temperature rise by 82 and 104?,respectively.The effect of TiN and TiC is better than that of Al₂O₃.They can also be used in thin-walled cylinders with high requirements,which deserves attention and further study.?4?The thicker the coating,the better the heat resistance of the thin-walled aluminum alloy cylinder.For Al₂O₃ coatings,when the thickness of the coatings is greater than 40 microns,the effect of increasing the thickness of the coatings on improving the heat resistance of Al₂O₃ alloys becomes smaller.?5?The corrosion resistance of 6061 aluminum alloy surface is greatly improved after anodizing.Moreover,the corrosion resistance of 6061 aluminum alloy after anodizing at low temperature?20??is better than that at high temperature?30??.Under proper technological conditions,the corrosion potential is-0.493V,and the self-corrosion current density is only 1.6×10^-5A/cm².