The Research On Guiding Roll Effect On Roundness Tolerance During Ring Rolling

Ring rolling is a specialized rolling process for manufacturing seamless rings,in which the diameter of the ring increases and the ring cross-section decreases by continuously local rolling.As an important part of ring rolling mill,guiding roll has important function during the whole rolling process.Guiding roll effect on roundness tolerance is researched by theory,numerical simulation and physical experiment.(1) Theory It is summarized the metal plastic deformation theory about ring rolling deformation and numerical simulation,ring rolling conditions on constant guiding force and characteristic of dynamic explicit algorithm.Guiding force required by ring rolling condition is derived from theory.(2) Numerical simulation Ring rolling model reflecting guiding force is set up by finite element analysis software ABAQUS,and mandrel speed and guiding force are checked.Simulation results show that 1) when guiding roll is located at the roiling exit,the roundness tolerance increases during the ring rolling process,it also increases when guiding force increases.But it does not show difference at different heights.Outer circle roundness tolerance is larger than inner circle's,but the difference decreases when guiding force increases.2) When guiding roll is located at the rolling entrance,at the beginning,large guiding force leads to smaller roundness tolerance,but later,small guiding force does so.And variable guiding force is good for roundness tolerance.Comparing guiding roll's two locations,when guiding roll is located at the rolling exit,the roundness tolerance is smaller.(3) Physical experiment Ring rolling experimental equipments are introduced and two groups of experimental program are proposed.In group A, Guiding force is constant,and rolling time is variable,in order to find the change of roundness tolerance during the ring rolling process.In group B,rolling time is constant,and guiding force is variable,in order to find guiding force effect on roundness tolerance.Experimental data confirms that when guiding roll is located at the rolling exit,the roundness tolerance increases during the ring rolling process,it also increases when guiding force increases.These researches help to find guiding force effect on roundness tolerance,and provide experimental data for precise numerical simulation.These are good for improving rolling quality of ring.