A stepped-section ring consists of two rectangular section rings,a big ring and a small ring,joined together.This kind of ring is difficult to process by the ring rolling technique because of its complex cross-sectional shape.Thus a reasonable blank design is necessary.In this paper,four blank designs,one is a rectangular cross-section and the other three are stepped-sections with different step volumes,are proposed and compared with each other using theoretical analysis,FE simulation and experiments.It is shown that three of the designs can lead to volume flow from small ring into big ring during rolling,which is disadvantageous for shape formation and dimensional precision;however,the other design may result in good ring shape and high dimensional precision.Therefore,the optimal blank design is determined to be the one in which the volumes of the big and small rings of the initial blank are equal to those of the final rings,respectively.
QIAN DongSheng & HUA Lin School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China
