Evaluation of New Hypothetical Concept (LHSIR) for Die Profile Design for Hydrostatic Extrusion Of AL/MG Compound

Abstract

This paper presents, for the first time, a new developed concept for design of Die pass profile used in hydrostatic-extrusion of Al/Mg compound. The new design criteria proposes a "Linearity" of the Homogeneous Successive Strain Increment Ratios (LHSIR) of the deformed material, instead of the "Constancy" concept (CHSIR) found in literature, as the tool base to generate the profile. The developed profiles were evaluated numerically to assess their relative pressure ratios as the main parameter for performance checking adopting the well-known Upper Bound Approach (UBA). A further developed aspect for the velocity field proposition is successfully made to carry out the necessary tedious computations. 12 different samples of commercial tool steel were CNC-manufactured, heat treated and tested to Al/Mg compound, from lead alloy, for sake of comparison and validity assessment. The major conclusion comes out of this work claims that a small variance in the classical constancy criteria of the Die design is very sensitive to change the expected levels of the relative pressure ratios of the extrusion process.