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چكيده انگليسي :

1 Simulation of Cold Extrusion of Non symmetric I Shaped Section Maziar Ghaeezadeh m ghaeezadeh@me iut ac ir 2011 Department of Mechanical Engineering Isfahan University of technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi M Moradi Assist Prof E mail moradi@cc iut ac ir Abstract Extrusion is one of the most important metal forming processes due to its high productivity lower cost and increases physical properties of the material In metal forming industry many kind of non symmetric rods are produced by the extrusion process For example extrusion from a round billet into a bar with various cross sectional shapes such as T L U and I etc by using aluminum alloys steels super alloys and titanium alloys are widely used However the process itself is difficult to analyze due to complex die shape and the rotational component of velocity that can cause unpredictable behavior of the metal flow during extrusion Metal flow does not remain in a radial plane passing along the longitudinal axis of the die and this behavior results in unusual stress and strain distribution in the deforming material The complexity grows even further in determining the optimum location of the exit section of the extrusion die particularly in the three dimensional 3 D extrusion of shaped sections Therefore attempts to obtain the optimum die configuration are still done mostly by applying the intuitive and empirical methods Some analytical methods for predicting the metal flow in order to obtain the optimum die configurations for various cross sectional shapes have been proposed by some workers Cold extrusion is an important metal forming process that some factor such as high pressure considerable die force friction influence cost of tools and appropriate mechanical properties should be considered One of the most important factors in extrusion process is to minimize the extrusion force in which the pressure on the mandrel and on the die reduced thus the life of die increased Those with minimizing it can reduce punch pressure and furthermore reduce abrasion of the die and container This reduction of pressure results in increasing the life of dies and process equipments With competitive industry and effort of workman to reducing costs and increasing quality it is necessary to understanding this condition Many kind of non symmetric rods are produced by the extrusion process On the other hand it is very important to have straight product in non symmetric shapes In practice most of the times a straight product is achieved by adding die lands to the die which increases the extrusion load and deformation of the metal significantly As mentioned above non symmetric I shaped section is also producted by extrusion Because of the unsteady velocity of metal flow non symmetric sections are not usually extruded in straight line By adding die land or in some cases by minimizing the distance between blank and extruded surface area centers attempts are made to achieve a straight product In this paper with ABAQUS software an extrusion simulation is made with Tellurium lead alloy Two kinds of die land and their effects on extrusion force are investigated The results are compared with available experimental ones in some references Key words Simulation Cold Extrusion Die Bearing Friction FEM Non symmetric tellurium lead

قائي زاده، مازيار

شبيه سازي اكستروژن سرد با مقطع I نامتقارن

لبه قالب , اصطحكاك , اجزا محدود , تلوريم سرب