Abstract
The geometric shape of the tools is the main factor by which an optimum technological process can be developed. In the case of extrusion process the strain distribution and other important variables that influence material structure, such as hydrostatic stress, are strongly dependent on the geometry of the die. Careful design of the extrusion die profile can therefore control the product structure and can be used to minimise the amount of inhomogeneity imparted into the product. A possibility to minimise the amount of product inhomogeneity is the using of a flat die with a fillet radius in front to the bearing surface with leads to a minimum dead zone and consequently to a minimum friction at billet-container interface. In the case of aluminium alloy type 2024, for an extrusion ratio of R=8.5, good results were obtained with a fillet radius of 3.0 mm. The experimental data have been used for the finite element numerical simulation of the extrusion process. The data obtained by numerical simulation with FORGE2 programme confirm the theoretical and experimental outcomes. The aim of this paper is to study the influence of such flat die on the material flow during direct extrusion process and consequently on extruded product microstructure and mechanical properties.
Highlights
Both the quality and accuracy of the extruded parts depend on a large range of factors such as: the type of the material being deformed, the way of its flowing during the deformation process, the type of the tools material, the stress state, the working temperature, the friction conditions, the type of the lubricants and how they are used etc.[1,2,3,4].() Trabajo recibido el día 5 de Junio de 2009 y aceptado en su forma final el día 20 de Abril de 2010. * “Stefan cel Mare” Suceava University, Str
Taking into account the above mentioned, the aim of this paper is to study the influence of such flat die on the material flow during extrusion process
In terms of optimisation of the material flow during deformation process the most favourable technological variant is the one which generates a uniform distribution of the particle velocities in the die opening[6, 7 and 9]
Summary
Both the quality and accuracy of the extruded parts depend on a large range of factors such as: the type of the material being deformed, the way of its flowing during the deformation process, the type of the tools material, the stress state, the working temperature, the friction conditions, the type of the lubricants and how they are used etc.[1,2,3,4].() Trabajo recibido el día 5 de Junio de 2009 y aceptado en su forma final el día 20 de Abril de 2010. * “Stefan cel Mare” Suceava University, Str. * “Stefan cel Mare” Suceava University, Str. Universitatii nr.13, 720228. ** “Dunarea de Jos” Galati University, Str. Domneasca nr.47, 6200. The most deformed metal layers in the final product are those located between the outer surface and the half of the radius of the extruded product. The intensity of deformation of central layers is often twice smaller than that of the layers located close to the surface. This flow mechanism leads to a considerable differentiation of the strain fields within the billet, and causes the non-uniform distribution of the total strain, microstructure and properties of the material over the product cross-section
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