Finite Element Simulation On Processing Of Large Special Shaped Ring Of Nickel-based Alloy

Based on the Simufact platform,a thermal-mechanical coupled three-dimensiona l finite element model was built and the ring rolling process of the large cont our ring of nickel based alloy ring was simulated.The influences of the frictio n factor between the rolled stock and main roll or mandrel roll,the feed spee d of mandrel roll,the peripheral speed of main roll,and the mandrel roll diam eter on the equivalent strain,rolling force and ring size during hot rolling of t he ring were studied.The results show that:(1)With the increase of the friction coefficients of the main roll(drive roll)and taper roll,the outer diameter of the ring becomes lager,and the inner diameter of the ring becomes will be increased when the friction coefficients of mandrel increases.Meanwhile when the friction coefficients of the drive roll increases,the radial and axial rolling force will be increased.The internal and external surface equivalent strain will be more uniform when the friction coefficients of drive roll increases,then the deformation become more homogeneous,and the plastic deformation will be more easily penetrated into the internal zone of the rolled ring.(2)With the increase of the feed speed of the mandrel,the plastic deformation will be more easily penetrated into the internal zone of the rolled ring,so that the deformation is more uniform,and the deformation area increased when the mandrel roll is through the radial pass each time,more metal occurs plastic deformation,so that the radial rolling force increases.The middle and outer diameter of the ring gradually become smaller with the increase of the plastic deformation area,and when the mandrel feed rate become too large,it will cause the local deformation to be too large,then it will increase the degree of ellipse easily,and resulting in the abnormal shape of rolled ring.(3)With the increase of the peripheral speed of main roll,the deformation is more concentrated in the surface area of the rolled ring,so that the increase of the equivalent strain at the surface of the rolled ring becomes more obviously than the core part.Then the plastic deformation area decreases when the ring through the radial and axial pass each time,and the rolling force is reduced.Because of the internal and external side of the rolled ring is more easily deformed,so the final value of the inner and outer diameters increase with the increase of the peripheral speed of the main roll.(4)With the increase of the diameter of the mandrel roll,the flow resistance of the metal in the surface of the rolled ring is increased in each radial pass.Thus,the equivalent strain at the inner surface of the ring is reduced.But in the axial direction,there are no obvious changes in the upper and lower surfaces.The contact area becomes larger between mandrel roll and inner surface of the ring,which causes more metal to be deformed,and makes the radial rolling force bigger,and there are no obvious changes in the trend of axial rolling force.The influence of the diameter of the mandrel roll on the size/dimension of the ring is not obvious.(5)For getting a suitable shape and size and uniform deformation product with almost no defects,the size of φ1500mm(external diameter)×φ860mm(internal diameter)×350mm(thickness)large contour ring of nickel based alloy is researched in this paper.By FEM simulation,we get a reasonable ring rolling process:the drive roll line speed is 1100mm/s,mandrel roll feed rate is 1.5~1mm/s,the friction coefficient of the drive roll,the mandrel roll and the tapper roll is 0.7,0.7 and 0.4,respectively.And the mandrel roll diameter is 280 mm.