Computer-aided metal flow investigation in streamlined extrusion dies

Metal forming by extrusion plays a pivotal role in metal forming processes which is widely accepted by industries. It is of interest to mention that the extrusion is conventionally carried out with the help of the shear faced dies. In these dies metal is forced to go through a sudden change in cross-section causing some practical problems such as formation of dead metal zone, non-uniformity in metal flow and more redundant work, etc. To overcome these problems, extrusion dies are presently modified as streamlined extrusion dies in order to ensure the smooth flow of metal and to avoid the formation of dead metal zone. In this paper, a modest effort has been made to analyze the metal flow in streamlined extrusion dies. The present investigation has been done for the streamlined extrusion dies designed based on the fifth order polynomial equation. The velocity components and strain rates along x, y, and z directions are determined in the fifth order polynomial equation based die profile. Based on the analysis carried out for extruding square and hexagonal sections from the circular billet, it is observed that the velocity components Vx, Vy, and Vz increase with an increase in the extrusion ratio. However, the rate of increase is less for hexagonal section as compared to the square cross section for the same extrusion ratio.