Proposition of Simultaneous Hybrid Forming with Burring and Ironing Process by Finite Element Method
This paper describes a finite element method (FEM) analysis for cold burring process of large diameter SGP pipe. The large diameter pipes are used for a plant as a flow channel of gas and liquid. A burring process of pipe is generally for forming the branch. The burring process is achieved by drawing of die from prepared hole. And the branch pipe is welded to the formed pipe. This process has some problem. One is the forming limit of pipe, and the other is needed to machining the end surface to be welded. Each problems are depend on the prepared hole shape, thus the optimum prepared hole shape is required. In this study, FEM analysis was operated to estimate the optimum prepared hole shape. Prepared hole has two dimensions because of ellipse. At first, the length of longitudinal and circumferential direction of ellipse was estimated. Secondly, the measurement of the other point that was effected on the end surface shape was estimated. By performing burring and ironing process with a tapered punch using a stepped mold, appropriate pre-hole shape that enables welding only in the process of rigid body drawing that does not require end face cutting of the branched part in the post process estimated.
Keywords - Burring Height, Cold Burring Process, Finite Element Method Analysis, Forming Limit, SGP Pipe