Paper Title
Hybrid Forming for Branch Part of Steel Pipe by Burring and Ironing

Abstract
This paper describes a simultaneous hybrid cold forming by burring and ironing of steel branch pipe. The 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 problemisdepending on the prepared hole shape, and the optimum prepared hole shape is required. In this study, FEM analysis was operated to estimate the optimum prepared hole shape.A burring and ironing process was performed at the same time, and a machining method that does not require the end face cutting of the branch in the subsequent process was proposed. Keywords - Burring, Ironing, Simultaneous hybrid forming, Finite element method, Steel pipe