Research On Forming Process And Forging CAPP System Of Large Ring

As a key component of ultra supercritical thermal power unit and deep-sea pressure vessel,the rationality of forging process of large ring forgings will directly affect the normal operation and service life of the equipment.Taking F92 steel large ring flange and TC4 titanium alloy large ring as examples,aiming at the problems existing in the actual forging production,the forming process is deeply studied by the combination of numerical simulation and experimental verification.For the problems of cracks and concave defects in the production of large ring flange forgings of F92 steel,the common free forging process is simulated and analyzed,and the distribution and variation laws of temperature field,strain field,damage field and velocity field are revealed.It is found that the equivalent effect change reaches the maximum value of 15.20 at the place where the crack occurs,and the concave phenomenon appears in the inner hole of the forging,with the maximum diameter of 669.42 mm.Therefore,a forming process of near net shape extrusion riveting after multi pass drawing with small pressure is proposed.The simulation results show that the best effect is obtained when the reduction L=60mm,the equal effect variable value is reduced to 11.31,the maximum diameter of the outer concave is reduced to 630.68 mm,and the metal streamline of the forging is uniform.After trial production and body sampling test,it is found that the cracks and concave defects of annular flange forgings disappear,the mechanical properties are good,the microstructure is fine and uniform,and the qualified rate of products is increased from 25% to 80%.Based on the theoretical analysis of the two-stage process flow of free forging and ring rolling of TC4 titanium alloy large ring,the macro and micro coupling finite element models of radial and axial rolling of large ring are established on the DEFORM-3D platform,the different process schemes are numerically simulated,and the effects of the initial temperature of ring,the angular speed of driving roll and the feed speed of core roll on the physical quantities of formed ring are studied respectively.It is found that: With the increase of the initial temperature of the ring blank and the angular velocity of the driving roll,the temperature field and equivalent effect field of the formed ring change positively.With the increase of the feed speed of the core roll,the temperature field of the formed ring shows an upward trend as a whole,and the equivalent effect field shows a downward trend as a whole;Microscopically,the dynamic recrystallization degree and grain size of formed rings are affected by macroscopic physical quantities,and they always show the opposite evolution trend;The distribution uniformity of macro and micro physical quantities needs specific analysis,which is more complex.The simulation results provide a scientific basis for the actual production.In order to simplify the operation process of free forging numerical simulation,MFC object-oriented programming technology is used to combine the setting interface of CAE operation process with DEFORM-3D text mode to realize the multi-step automatic simulation forming of free forging,which greatly shortens the cycle of numerical simulation,and the operation of simulation software DEFORM-3D is more intelligent and convenient.The feasibility of multi-step automatic simulation forming is verified by application example simulation analysis.In order to make the forging process more standardized,the secondary development of large ring forging CAPP system is carried out by using C++ programming language in NX environment.The mutual transmission of NX and Excel data is realized through OLE Technology in vs Software.On this basis,the model expression and process card template of ring forging are established,and the functions of parametric modeling,engineering drawing,printing and export of process card are realized in NX environment.Finally,the deform multistep automatic simulation forming interface is integrated into the CAPP system,which realizes the seamless connection from the first process draft to simulation analysis and then to the final process draft archiving.The whole system is more intelligent and perfect.