Research On Rolling Technology Of Conical Ring With Inner Steps And Ring Rolling Mill

Ring rolling is a specialized rolling process for manufacturing seamless rings, in which the diameter of the ring increases as the ring's cross-section area decreases by rolling. It has many characteristics such as saving forming force and production cost, increasing utilization ratio of energy and material, rising productivity and widening processing range of ring products etc. It is widely employed in many industrial domains. The most attractive domain of ring rolling technology is to roll the rings with specially-shaped cross section directly. But the rolling deformation law of ring with specially-shaped cross section is more complicated compared with rectangle section ring and in the process there are lots of special phenomenon such as underfilling, shrinking-drawing, concave, saucer shape and etc. These phenomenon are the objective reflection of the rolling deformation law of rings with specially-shaped cross section. So it's necessary to study, understand, master and apply the rolling deformation law of rings with specially-shaped cross section flexibly if we want to obtain the qualified rings with specially-shaped cross section by rolling.Conical ring with inner steps is a typical ring with specially-shaped cross section. The research method of combining numerical simulation with experiment is taken to study the rolling technology of conical ring with inner steps. A brief introduction to the project and its main results are as follows:Based on the theories of elastic-plastic finite element method and the theories of ring rolling, the calculation model of rolling process of lead conical ring with inner steps is established and calculated by dynamic algorithm finite element program. Through simulation the mechanism of rolling deformation defects of lead conical ring with inner steps is revealed, the flow law of metal and the rolling energetic parameters are analyzed and the effects of ratio of height to diameter on the rolling deformation law are studied.According to the rolling defects of lead conical ring with inner steps, the ring blank dimension and rolling groove are optimized. The simulation results show that the flow of metal is improved obviously by using the optimized ring blank and groove. The rolling experiment with lead as blank material is made in D51-160A hot ring rolling mill and the qualified pre-rolled ring of conical ring with inner steps is rolled. The simulation and experimental results verify that the optimized scheme is reasonable. The distribution law of horizontal cross section area of ring forging and ring blank is put forward to describe the rolling formability of conical ring with inner steps. The simulation results show that the distribution law of horizontal cross section area of ring forging and ring blank can describe the rolling formability of conical ring with inner steps validly, at the same time, it can predict the rolling defects exactly and...