The Numerical Simulation Of Ring Rolling Process

The process of ring parts rolling is a technology by giving continuous press to ring parts locally, using rotated driving roll die, and make the ring parts compressed in radial direction and stretch in circle direction, the radial thickness of ring parts reduced, the radius of ring parts grew, it rotated locally, it's section formed continuously, ring parts rolling is also a main process to seamless ring parts. In the processing of ring parts rolling, driving roll are main roll, it rotate itself and forward to ring part; the support roll is a following roll, it rotated itself by the friction force of ring parts. Guide roll is a free roll, it only rotates itself, and it makes the rolling process steady. Ring parts rolling is a process between rolling and mechanical produce, The superiority of rolling process makes itself have a wider and brighter foreground. Currently, the common products made by rolling process are bearing ring, wheel gear ring, the wheel and hub of train, ring of internal-combustion engine and collecting ring etc.The main research in the text contain three points: The ring rolling while driving roll have different radial rate; influence of Rough design on ring rolling; influence of guide roll position on ring rolling. The conclusions are as follow:(1) The influence of driving roll radial rate on ring rolling According to ring rolling theories and ring rolling techniques, the maximum and the minimum rotate speed can be computed, and the maximum and the minimum driving roll radial rate also can be computed. The result show that while rotate speed is given, ring part appeared plastic strain while driving roll at minimum radial rate, when driving roll is given max radial rate, ring part occurred plastic at the beginning of ring rolling, then the ring part bended more, and driving roll begin sliding on the surface of ring parts. These ring rolling phenomenon testified the margin rate of driving roll radial rate. From simulation result of ring part, we found that while driving roll radial rate are different, the max radius of rolled ring parts are different, for example, as driving roll radial rate is 0.2mm/r, ring part diameter began increased very slow after outer diameter increased to 66.4mm, inner diameter went up to 43.6mm.according the result of radius begin to increase slowly. Using the relation a driving roll rate can be easily gained, while a certain radius is needed. The relation between radius increase and driving roll radial rate are useful for ring parts technical design and rough part design.(2)Rough design has effect on ring rolling According ring rough design theories and rolling scale, a ri rough was designed, form the simulation result, something was found that rin art radial thickness effect more on ring rolling precision, the more radial thick of ring part, the big axis strain ring part. So, two ring rough were designed, the first ring rough its outer radii is 62mm, inner radii is 31mm is more difficult rolled, the second ring rough with outer radii 67mm inner radii 40mm rolled easily. And the second ring rough have better rolled precision.(3)The influence of guide rolls position on ring rollingIn the text, two processes were designed to simulate the position of guide roll. First, when guide roll is fixed ,its influence on ring rolling; Second, the influence of unfixed guide roll on ring rolling, in the second process, guide roll could moving as ring part radius increasing. when guide roll is fixed, four status were simulated, those are status when guide roll angle is 80°,90°,100°,115°,130°,the result of simulation showed that when guide roll is 90°the rolled ring have better quality, ring part axes strain is fewer. While guide roll angle is 80°or 100°, the size error of ring part is large than that when guide roll is 90°. the axis strain of ring part are more close when guide roll angle is 80°and 100°, when guide angle is 115°,the increase of outer radius is held by guide roll, so the rolled ring part appears to be ellipse. When guide roll angle isl30°, the rolled ring part has been out of round. As guide roll can be moving follow ring parts outer radius, a math equation can be gained form side length relation in one triangle, as the equation is given to guide roll, the speed of guide roll can be computed in the equation. The result of Guide roll angle 90°show that the size error of unfixed guide roll are fewer than that fixed guide roll.(4)The influence of rolling force on ring rollingThe result of ring rolling showed that uniform driving roll force range 18~25kN, and the bended force of ring part is 8.68kN, when driving roll force reach 8.68kN, ring part begin bended at outer radius surface, but middle radius surface won't bended until its force reach 8.68kN.for example, as driving roll rate is 0.2mm/r, the force of middle radius surface is less than 8.68KN, so, the strain of ring part distributed close to outer and inner radius surface. A appropriate guide roll force range 0.5~4kN, and the more guide roll force change the worse steady of ring rolling.