Numerical Simulation Of Extrusion Forming Of Double-end Inner Thickened Aluminum Alloy Drill Pipe

With the development and progress of oil and gas exploration technology,the development direction of it at home and abroad has gradually shifted to deep wells,ultra deep wells,extended reach wells,directional wells and wells containing hydrogen sulfide and carbon dioxide.Meanwhile,the aluminum alloy drill pipe(ADP)has been widespread concern and applied in the word for its well mechanical properties and corrosion resistance when used in these wells.However,domestic development of ADP is still in trial manufacture stage,and many key technologys are to be tackled in tube forming and quality compared with Russia,the United States and other ADPs main production countries.Therefore,it is of great significance to carry out research on the forming process,quality and material design of ADP,which is helpful to guide forming process optimization of ADP,and accelerate the trial production and mass production of ADP.In this paper,the extrusion process of ?73 mm ADP with double ends inner upset was simulated by the Deform-3D numerical simulation software in 7075 aluminum alloy and 15%volSiCp/7075 composite,respectively.The influence of geometry morphology of mould and extrusion parameters on deforming process and quality of formed tube was investigated by the stress contours of ingot and effective strain distribution of tube during deforming,damage of tube external surface,dynamic recrystallization,and geometric devaiton of formed tube.And the optimization deforming craft of ?73 mm ADP with double ends inner upset was achieved.On the othe hand,the difference of formed tube ?73 mm ADP tube with double ends inner upset on damage,dynamic recrystallization of external surface and geometric deviation was mainly investigated by comparing their deforming quality between 7075 aluminum alloy and 15%volSiCp/7075 composite,with the effect degree of each forming craft on forming quality of tube achieved.Meanwhile,the extrution trail of upset end and main body of ?73 mm ADP tube was conducted to verify the inhomogeneous distribution of dynamic recerystallization.Finally,the compress deformation of 6.5%SiCp/7075 compostite with one particle was developed by Deform-3D.And the influence of interface material and particle morphology on compressional behavior of composite cell was discussed from stress and temperature contous of matrix,interface,particle,and strain and damage contous of matrix.The simulation and experimental results show that,damage factor of external surface,axial difference of dynamic recrystallization percentage and average dyanamic recrystallization grain size,external diameter deviation and thickness deviation is large for?73 mm ADP with double ends inner upset in 7075 aluminum alloy by extrution at once time.When matrial of ADP is 7075 aluminum alloy,the optimized moulds geometric morphology is angle of flat cone die 63°and length of mandrels cone section 12.5 mm,and the optimized extrusion parameter is extrusion ratio 25,extrusion temperature 400?,and extrusion speed 1.12 mm/s.When matrial of ADP is 15%vol SiCp/7075 composite,the optimized moulds geometric morphology is angle of flat cone die 60° and length of mandrels cone section 12.5 mm,and the optimized extrusion parameter is extrusion ratio 25,extrusion temperature 380 ?,and extrusion speed 1.52 mm/s.on the other hand.When the interface material is SiO2 and the paticle morphology is sphere,the damage of matix decreases for compression of 6.5%SiCp/7075 composite.