Mechanical and microstructural performance of convex dies in axisymmetric extrusion—Theory and experimental verification

Kazanowski, Pawel; Browne, Heather M.; Libura, W.; Misiołek, Wojciech Z.

doi:10.1016/j.msea.2005.05.076

Cited by 9 publications

(7 citation statements)

References 1 publication

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“…44 shows that the CAFE model predicts higher strain localization in the shear band area than the conventional FE model. It agrees qualitatively with experimental observation, see for example [53,75].…”

Section: Extrusion With Convex Diessupporting

confidence: 92%

“…On the other hand, extrusion leads to nonhomogeneous structures and mechanical properties of final products. A coarse grain layer occurs close to the surface and leads to deterioration of product exploitation properties [53,75]. This is mainly due to the existence of a dead zone and strain localization in the deformation area.…”

Section: Extrusion With Convex Diesmentioning

confidence: 99%

“…The problem of shear band formation leading to strain localization in materials during deformation has been investigated by scientists for over thirty years. Much effort has been made both experimentally and theoretically to study shear band propagation during various kinds of deformation: compression [2,18,27,100], rolling [28,32,33,54,56,72,77,99] and extrusion [53,75]. As a result of these studies several forming processes, which benefit from the change of deformation path and shear band propagation, have already been designed and used in industry [10,55,60,62,113].…”

Section: Introductionmentioning

confidence: 99%

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Development of the Multi-scale Analysis Model to Simulate Strain Localization Occurring During Material Processing

Madej

Hodgson

Pietrzyk

2009

Arch Computat Methods Eng

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A detailed description of possibilities given by the developed Cellular Automata-Finite Element (CAFE) multi scale model for prediction of the initiation and propagation of micro shear bands and shear bands in metallic materials subjected to plastic deformation is presented in the work. Particular emphasis in defining the criterion for initiation of micro shear and shear bands, as well as in defining the transition rules for the cellular automata, is put on accounting for the physical aspects of these phenomena occurring in two different scales in the material. The proposed approach led to the creation of the real multi scale model of strain localization phenomena. This model predicts material behavior in various thermo-mechanical processes. Selected examples of applications of the developed model to simulations of metal forming processes, which involve strain localization, are presented in the work. An approach based on the Smoothed Particle Hydrodynamic, which allows to overcome difficulties with remeshing in the traditional CAFE method, is a subject of this work as well. In the developed model remeshing becomes possible and difficulties limiting application of the CAFE method to simple deformation processes are solved. Obtained results of numerical simulations are compared with the experimental results of cold rolling process to show good predicative capabilities of the developed model. L. Madej ( ) · M. Pietrzyk

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Section: Extrusion With Convex Diessupporting

confidence: 92%

Section: Extrusion With Convex Diesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development of the Multi-scale Analysis Model to Simulate Strain Localization Occurring During Material Processing

Madej

Hodgson

Pietrzyk

2009

Arch Computat Methods Eng

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“…Upper bound method is a commonly used method in engineering, which can be used to estimate the force and power parameters in the forming process, analyze the deformation of metal flow and optimize the design of process parameters and dies. Based on the upper bound method, Kazanowski et al [20] studied the influence of die structure change on extrusion results, and obtained the optimal process parameters. Zhou et al [14,15] compared the upper bound method with FE modelling and process experiment, divided the dead metal zone and plastic deformation zone in the model, and further optimized the model, which can more accurately predict the curvature of the extrusion.…”

Section: Introductionmentioning

confidence: 99%

An Analysis for Magnesium Alloy Curvature Products Formed by Staggered Extrusion (SE) Based on the Upper Bound Method

Zhang

Wang

et al. 2021

Preprint

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Staggered extrusion (SE) is a new method to solve the bottleneck of traditional curvature products, such as long manufacturing cycle, many forming processes and difficult quality control. How to quantitatively control the curvature of extruded products is the key to implement this method. Herein, the upper bound method is used to calculate and analyze the power consumption of each characteristic zone in the SE process. The theoretical model of extrusion load and curvature is established. The results show that the staggered distance h has an important influence on the curvature κ. When the staggered distance h increases from 8 mm to 24 mm and other conditions remain unchanged, the curvature κ increases from 0.0546 to 0.1607. Any combination of the staggered distance h and the extrusion ratio λ corresponds to an eccentricity ratio ξ. The eccentricity ratio ξ decreases with the increase of the staggered distance h or the extrusion ratio λ. By comparison, it can be seen that the variation trend of the theoretical predicted value and the FE modelling in the steady-state extrusion stage is consistent. The experimental results are in good agreement with the curvature theory prediction model. These results provide a scientific basis for the formulation of the SE process and precisely controlling magnesium alloy curvature products.

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“…Kazanowski et al [11] , carried out experiments on convex dies and concluded that this kind of dies outperform the flat face dies only for extrusion ratios below 30. According to Tokizawa et al [12] , when the die semi-angle becomes larger, the pressure acting on the bearing surface tends to decrease.…”

Section: Introductionmentioning

confidence: 99%

Effect of die shape on the metal flow pattern during direct extrusion process

Solomon¹,

Solomon²

2010

REVMETAL

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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. KeywordsMetal flow pattern; Flat die; Friction; Finite element; Equivalent strain.Efecto de la forma del molde sobre el flujo de metal durante el proceso de extrusión directa ResumenLa forma geométrica de las herramientas es el principal factor a través del cual un proceso óptimo de deformación plás-tica puede ser mejor desarrollado. En el caso del proceso de extrusión, la distribución de la deformación y otras variables importantes, como la presión hidrostática, que pueden influir en la estructura del material, son fuertemente dependientes de la geometría del molde. Mediante un diseño apropiado del perfil del molde de extrusión se pueden controlar la estructura y las propiedades mecánicas del producto y, por lo tanto, se puede utilizar para minimizar la cantidad de la no homogeneidad del producto. Una posibilidad para reducir al mínimo la cantidad de no homogeneidad del producto es utilizar un molde recto provisto de un radio de conexión en la zona de deformación, que puede causar una reducción al mínimo de la zona muerta y, así, reducir al mínimo la fricción en la interfase entre el semiacabado y el contenedor del molde. En el caso de la aleación de aluminio de tipo 2024, para una relación de extrusión, R = 8,5, los mejores resultados se obtuvieron con un radio de conexión de 3,0 mm. Los datos experimentales se utilizaron para la simulación numérica del proceso de extrusión. Los resultados experimentales obtenidos mediante el uso de simulación numérica con el programa FORGE2 confirman los resultados teóricos y experimentales. El propósito de este trabajo es estudiar la influencia de este tipo de matrices con un radio de conexión en la zona de deformación en el flujo de material durante el proceso de extrusión y por tanto en la microestructura y...

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Mechanical and microstructural performance of convex dies in axisymmetric extrusion—Theory and experimental verification

Cited by 9 publications

References 1 publication

Development of the Multi-scale Analysis Model to Simulate Strain Localization Occurring During Material Processing

Development of the Multi-scale Analysis Model to Simulate Strain Localization Occurring During Material Processing

An Analysis for Magnesium Alloy Curvature Products Formed by Staggered Extrusion (SE) Based on the Upper Bound Method

Effect of die shape on the metal flow pattern during direct extrusion process

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