Simulation And Experimental Research On Macroscopic And Microscopic Deformation Behaviors In Hot Ring Rolling Of GCr15Bearing Ring

Ring rolling is an advanced continuous local forming technique which to reducethe thickness, enlarge the diameter and form the profile of the workpiece. Comparedwith traditional die forging, it has high productivity, material saving benefits, low cost,good internal quality, it can be applied widely in many industrial departments, such asbearing ring, gear ring, flange ring, train wheel, gas turbine ring, engine ring and seatof anti-aircraft gun. At present, a lot of research of macro deformation has beeninvestigated. However, the researches of ring rolling are concentrated just in therolling step; the research of the whole process (upsetting, piercing, leveling and ringrolling) has rarely been studied. Consequently in this paper, the macroscopic andmicroscopic deformation rules were investigated in the whole process.In this paper, based on the SIMUFACT platform, the3D coupledthermo-mechanical FE model of hot ring rolling was established, and the models wasproved to be reliable by being compared with experimental and simulative results.Based on the FEM models, the distribution and evolution laws of strain, temperature,grain size and dynamic recrystallization during hot ring rolling was investigated; theeffect laws of the initial temperature, height-diameter ratio, upsetting speed, the feedrate and rotation speed of main roll, the sizes of rolled ring on macro-microdeformation behaviors of hot ring rolling were deeply discussed, respectively. Thedistribution laws of grain size and recrystalliztion during hot ring rolling werediscussed; the effects of technological parameters (feed rate of the main roll,rotational speed of the main roll, initial temperature of the ring and friction factor) onthe micro deformation were investigated. The study provided a theoretical basis forthe design and optimization of the rolling parameters in the process of actualproduction.In addition, the microstructure and performance were researched in wholeprocess of hot ring rolling by test method. Based on the optical microscope, the grainsize of the whole process has been observed; the piece of spacing of pearlite wasmeasured with SEM, the change rules of microhardness and mechanical property inwhole process were observed by microhardness test and compressive experiment. The results provide an important theoretical basis and practical significance forestablishing the hot ring rolling theory and improving the microstructure properties ofhot rolled rings.