Research On Theoretical Parameters And Process Of Flexible Forming Of Seamless Metal Tube

Large diameter thin-walled seamless metal pipes are widely used in aerospace,building materials transportation,and other fields.However,due to problems such as deformation and residual stress during processing,there are many production defects and low yield.Cast-rolling process can achieve the one-time forming of liquid metal to solid finished products,with advantages such as near net forming and convenient operation,which has been widely concerned by metal pipe practitioners.However,research on the production of large diameter thin-walled seamless pipes is still lacking.In this paper,the spiral casting and rolling process for producing large diameter seamless metal tubes proposed by our research group is adopted,and 6061 aluminum alloy seamless tubes are taken as the research object.The research focuses on equipment design,simulation simulation,steel/aluminum solid-liquid composite,experimental verification,and other aspects.Based on the spiral casting and rolling process,this article uses Abaqus software to conduct thermal-mechanical coupling simulation of the rolling process with or without forming rollers.It analyzes the rolling process from the aspects of mechanical behavior and plastic deformation,and determines the position of the first forming roller under natural bending.It explores the impact of different parameter forming roller groups on the bending degree of each node of the rolled tube blank.Using the theoretical fitting degree of the tube blank circle as a criterion,the diameter,number.The optimal parameters for the location distribution.By using Fluent software,the spiral casting and rolling process was simulated by heat-flow coupling,and the evolution rule of the casting and rolling zone over time was analyzed,as well as the influences of roll assembly Angle,casting and rolling speed,casting temperature and molten pool height on the molten pool.The optimum parameters for producing seamless metal tubes with diameter thickness ratio of 100,60 and 40 were determined from the aspects of temperature field,flow field,KISS point curve and temperature distribution of remelted tube billet.The range values of roll Angle and width of remelted tube blank are derived and the limit diameters of tube blank specifications produced by spiral casting and rolling process are given.Under the guidance of three optimal parameters,auxiliary equipment such as a molding machine are added to the spiral casting mill.Experiments are conducted from the perspectives of tube casting,microstructure,and tensile testing.The feasibility of the spiral casting process is determined by analyzing the surface quality of the tube billet,the remelting bonding strength,and the spiral angle of the tube billet.Fluent fluid simulation software was used to numerically simulate the composite pipe formed by adding steel fiber metal matrix to the pipe blank.The effects of fiber diameter and fiber preheating temperature on the temperature field,flow field,and temperature distribution of the composite weld pool were analyzed,and appropriate process parameters were determined.Experiments on the steel/aluminum solid-liquid spiral casting composite pipe were conducted using these parameters,to explore the feasibility of producing this kind of composite pipe by spiral casting and rolling process.