On Deformation Laws And CAPP System For Radial-axial Ring Rolling

Radial-axial ring rolling is an advanced plastic forming technology to manufacture large rings, in which the radial thickness and axial height of ring decrease in radial and axial passes, respectively. Compared to traditional free forging large ring manufacturing technology, radial-axial ring rolling has the characteristics of low power, high productivity, high precision and good quality product. There exits wide applying prospective for this technology in many industrial fields, such as machine, automobiles, trains and aerospace vehicles.Based on the principle of kinematics, the diameter increasing rule and rotation of ring in rolling were researched. The rate and acceleration expressions of ring diameter increasing and rotation were obtained, from which the influencing factors and laws to ring kinematics were indicated. The feeds of idle roll and axial cones were analyzed. Meanwhile, the rotations of driver roll and axial cones were researched. By analyzing the motion track of guide roll, the displacement expression of guide roll at any time in rolling was obtained. The researches provided not only theoretic bases for controlling of rolls but also references for boundary conditions of ring and rolls in finite element simulation.The thermo-mechanical coupled FE simulation of radial-axial ring rolling was made for the first time by using thermal rigid-plastic material model and dynamic explicit finite element method under ABAQUS/Explicit environment. From the aspects of geometry dimension, material properties, contacts, thermal and mechanical boundary conditions, and meshes, according to concrete rolling parameters, the constructing course and method of FE model were introduced in detail. The rolling result was researched and discussed. The study provided a base for simulation and research on radial-axial ring rolling technology.From the view of static and plastic forming, by constructing physical and mechanical models and using force analytical method, the rolling conditions were researched based on the radial ring rolling theory, including the bite condition, penetration condition, and the ring stiffness conditions under radial rolling with one guide roll and radial-axial rolling with two guide rolls. The corresponding expressions of these rolling conditions were all obtained. The influencing factors and laws to these conditions were discussed in detail. The results of FE simulation verified the validity of theoretic analysis. Based on plastic deformation theory, the origin of width spread in radial-axial ring rolling was researched. The influencing factors and rules on width spread in radial and axial passes were analyzed by using the principle of shortest normal line. The dimension of width spread was calculated, which was used to revise the rolling condition expressions. Finally, by using FE simulation and practical rolling experiments, the shape, dimension and change of width spread in both radial and axial passes were analyzed.Taking radial-axial large ring rolling as an example, by using finite element simulation and radial-axial rolling theory analysis, the influencing laws of various blanks and technology parameters to rolling deformation were researched, which revealed the forming mechanism of radial-axial ring rolling. The rational blank and technology parameters design methods were analyzed. The practical rolling manufacturing proved the result of finite element analysis.Integrating the research result of radial-axial ring rolling theory with manufacturing experiences of large ring, the CAPP system (CAPP_RARR V1.0) for radial-axial large ring rolling was developed by using the program language of Visual Basic. This CAPP system included the database of material properties, and enclosed all the rolling condition, optimization design of blank and technology parameters with the form of program language, which can improve the efficiency of technology design and computing accuracy. By this way, the alternating design of ring blank, technology parameters and force parameters can be realized.