Metal Flow Conditions in Porthole Channels of Different Size

Abstract:

Finite element analysis (FEA) is applied to study metal flow in an asymmetric porthole die with two ports where one port is bigger than the other. It is shown how FEA predicts the velocity differences between the two ports to depend on applied extrusion velocity, i.e., the ram speed, and in addition, how increasing size difference between the ports changes the flow balance between the ports. Two of the simulations have been validated by experiments in previous work, so the trends shown by FEA have also been confirmed experimentally. In long billet extrusion metal flow through the two die channels is predicted stable throughout the major part of the extrusion stroke. However, in the end stage of the process, there is predicted a shift in metal flow. Now the velocity in the small channel is speeded up on the expense of that in the big channel. In short billet extrusion the same shift in metal flow is also confirmed towards end of extrusion. An explanation is given why the metal flow in the small channel speeds up towards end of extrusion. In the article it is also quantified (in a diagram) how big the shift in flow balance between the two ports is as the size difference between the ports increases.

• Periodical: Key Engineering Materials (Volumes 611-612)
• Pages: 1005-1012
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.611-612.1005
• Online since: May 2014
• Authors: Henry Valberg*, Dirk Nolte, Khan Yawar
• Keywords: Experimental Metal Flow, FEA-Predicted Metal Flow, Flow Velocity, Idealized 2D Extrusion Welding, Location of Extrusion Seam Weld, Metal Flow through Two Portholes, Porthole Extrusion

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