Simulation Of Extrusion Research Articles

Manufacture of multipurpose composite and ceramic materials in the combustion regime and high-temperature deformation (SHS extrusion)

The results of developing the process of SHS extrusion in order to produce long dimensional products of brittle and hardly deformed powders of refractory inorganic compounds are presented. In this process, the synthesis of material and the formation of billets takes few seconds in a single technological cycle. The experimental study of the rheological behavior of SHS materials and their ability to plastic deformation at high temperature region are discussed. A review of the experimental studies concerning the issue of the structure formation and properties of extruded SHS materials is presented. The main aspects of the mathematical simulation of SHS extrusion and pressing are highlighted, which were the key to correctly understanding the regularities of the high-temperature compression and molding final products from the combustion products. There are examples of the practical application of the developed SHS extrusion method for manufacturing the long-dimensional products using new multifunctional materials, including composite ceramic materials with nanosized structural elements; materials based on the MAX phase of the titanium system, i.e., aluminum-carbon; and intermetallides based materials.

Investigation of the process energy demand in polymer extrusion: A brief review and an experimental study

Extrusion is one of the fundamental production methods in the polymer processing industry and is used in the production of a large number of commodities in a diverse industrial sector. Being an energy intensive production method, process energy efficiency is one of the major concerns and the selection of the most energy efficient processing conditions is a key to reducing operating costs. Usually, extruders consume energy through the drive motor, barrel heaters, cooling fans, cooling water pumps, gear pumps, etc. Typically the drive motor is the largest energy consuming device in an extruder while barrel/die heaters are responsible for the second largest energy demand. This study is focused on investigating the total energy demand of an extrusion plant under various processing conditions while identifying ways to optimise the energy efficiency. Initially, a review was carried out on the monitoring and modelling of the energy consumption in polymer extrusion. Also, the power factor, energy demand and losses of a typical extrusion plant were discussed in detail. The mass throughput, total energy consumption and power factor of an extruder were experimentally observed over different processing conditions and the total extruder energy demand was modelled empirically and also using a commercially available extrusion simulation software. The experimental results show that extruder energy demand is heavily coupled between the machine, material and process parameters. The total power predicted by the simulation software exhibits a lagging offset compared with the experimental measurements. Empirical models are in good agreement with the experimental measurements and hence these can be used in studying process energy behaviour in detail and to identify ways to optimise the process energy efficiency.

Effect of Y and Heat Treatment on Microstructure and Deformation Performance of ZK60 Alloy

The ZK60 magnesium alloys add Y were deformed with extrusion simulation system, and extruded products for various heat treatment processes. The mechanism properties of Y element in ZK60 and its effect on microstructure were analyzed. as well as heat treatment process for ZK60 and ZK60 +1.0Y two influence of alloy microstructure and properties were investigated. The results showed that the addition of rare earth Y can effectively refine the grain ZK60 alloy, and can significantly improve the performance of ZK60 alloy plasticity. Artificial aging treatment can improve ZK60 and ZK60 +1.0Y alloy yield strength and ductility, the best artificial aging treatment ZK60 and ZK60 +1.0Y alloy extrusion products for the 180°C×24h.

Simulation and optimization of extrusion of cylindrical billets of plasticized powder and composite charges on screw extruders

A mathematical model for computing the extrusion of long billets of plasticized powder and composite charges on screw extruders through facilities with a local sectional area reduction of the forming channel is represented. The stress field calculation in the various material deformation centers along the overall length of the channel is carried out with the use of the discrete material plasticity theory. It is shown how to select their combination optimal for extrusion process by varying the form of the channel surface, the material extrusion rate in the zone of local channel section reduction, and the billet-section area.

Negative Pressures in Modelling Rotating Polymer Processing Machinery Are Meaningless, But They Are Telling Something

Abstract In the technical literature, some authors have reported calculation of negative pressures in simulations of twin screw extrusion and other types of processing, without giving any explanations. In the majority publications there is no mention of such meaningless results, even though theoretical considerations indicate that negative pressures could be obtained in the expansion region of drag flows through narrow non-parallel surfaces. The meaningless negative pressures are due to the application of single fluid theory to flow regions where bubbles would form, when the pressure drops below the vapor pressure of the liquid. This has been known for a long time from the study of lubrication bearings and related cavitation phenomena. It is argued that the boundary conditions should be carefully chosen for avoiding results in numerical simulations, which can never be reconciled with experimental pressure data.

Wear Progress of Nitrided Layer at Low, Medium and High Contact Pressures During a Laboratory Simulation of Aluminium Hot Extrusion

The progress of wear associated with the compound and diffusion layers of nitrided samples was studied by employing laboratory tests at low, medium and high contact pressures, simulating the conditions occurring during the hot extrusion of aluminium. It was found that with increasing of contact pressure also wear rates increase that indicates on predominately frictional removal of compound layer which was confirmed by scanning electron microscopy and back-scattered electron micrographs as well as energy-dispersive spectroscopy analysis of tested surfaces. Testing at medium contact pressures reveals some common features observed at testing at lower as well as at higher contact pressures. The essential difference between the testing at medium and low contact pressures is in the density of the obtained micro-craters and appearance of their extension in sliding direction at medium contact pressures. At higher contact pressure, removal of compound layer is already preferentially oriented in sliding direction in the first stage, while at medium contact pressure, this is observed only in later stages of degradation progress.

Computational Modeling of Die Swell of Extruded Glass Preforms at High Viscosity

Computational simulations of glass extrusion are performed to quantify the effects of material behavior and slip at the die/glass interface on the die swell. Experimental data for three glass types are used to guide the computational study, which considers glass material to be viscous with and without shear thinning and viscoelastic using the Maxwell upper‐convected model. The study starts with assuming no‐slip at the glass/die interface to see if material behavior alone can explain the die swell results, and then considers slip using the Navier model where interface shear is directly proportional to the relative slip speed at the interface. Consistent with the possibility of slip and intended high viscosity applications, viscosity ranging from 107.4–108.8 Pa·s was used. Based on optimization of the various input parameters required to achieve the measured die swell and ram force values, the study concludes that interface slip occurred as only extreme values of the shear thinning parameters provided an alternative.

The effects of billet temperature on compound extrusion of magnesium alloy by three-dimensional finite element modeling and experiments

Extrusion–shearing of magnesium billets is associated with large deformations, high strain rates and high temperatures, which could result in many difficulties in process. Thermo-mechanically coupled three-dimensional finite element simulations of extrusion–shearing wrought magnesium alloy AZ31 into small rods at certain speed have been performed, and computed parameters including workpiece material characteristics and process conditions (billet preheated temperature, extrusion ratio, ram speed, friction factors and heat transfer coefficients) have been taken into consideration. The temperatures and stress and strain rates of extrudates with different billet preheated temperature have been calculated by finite element method software DEFORM-3D. A series of extrusion–shearing experiments and microstructure observations have been done to perform tests in order to validate the finite element method simulation results at different preheated temperatures of billets. Surface defects of rods for magnesium alloys extruded by the extrusion–shearing extrusion have been observed and analyzed. The influences of preheated temperature on the microstructures and the causes have been given. Finite element method software DEFORM-3D has been used successfully to simulate the temperatures and stress and strain rates under three different extrusion conditions. The results of these simulations helped to understand the formation of surface defects in the surface of extrusion–shearing rods. These results could assist in improving quality of extrusion–shearing extrusion.

Investigation on Finite Element Simulation of ECAE with Variable Back Pressure for 7075 Aluminum Alloy

The numerical simulation of equal channel angular extrusion (ECAE) with variable back pressure was researched by applying the commercial Deform-3D software, in which choosing the hard deformation materials of 7075 aluminum alloy, and comparing the traditional ECAE without back pressure process. The influence of back pressure on the mean stress and the effective strain rate in the shear deformation zone was studied. The results show that the extrusion force transformation laws were different in both load ways, with the increase of back pressure, extrusion force enhances increasingly, but the final load-time curves tended towards stability, but in ECAE without back pressure, the final load-time curves tended towards decreasing; thus the whole deformation process can be divided into different stages. In addition, the larger the absolute value of the hydrostatic stress at the corner, the more beneficial to refine grain and improve the plasticity. The back pressure makes the distribution of effective strain rate in plastic deformation area more uniform and improves the uniformity of deformation.

Simulation of Composite Hot Extrusion with High Reinforcing Volumes

Experimental results, which indicate a significant influence of the reinforcing elements on the material flow during composite extrusion with high reinforcing volumes, are presented. In order to analyze the process numerically, finite element simulations with models taking into account the reinforcing elements were carried out. The results are discussed with regard to the material flow and the load of the reinforcing elements.

Finite element method simulation of the hot extrusion of a powder metallurgy stainless steel grade

Oxides Dispersed strengthened (ODS) stainless steels are foreseen for fuel cladding tubes in the coming generation of fission nuclear reactors. In spite of a ferritic matrix those steels present a convenient creep behavior thanks to very fine oxides dispersion. Those grades are currently obtained by Powder Metallurgy (PM). After mechanical alloying with the oxide, the powder is commonly consolidated by Hot Isostatic Pressing (HIP) or Hot Extrusion (HE). The control of microstructure after extrusion is a key issue for this grade regarding service conditions. On CEA facilities, new ferritic ODS stainless steels are produced by HE. In order to explain the microstructure observed at various places on an interrupted extrusion samples the thermo-mechanical history applied to the material must be determined. In this paper we use the Finite Element Method to simulate the co-extrusion of a PM grade in a soft steel can. The PM steel grade behavior law is determined on a fully dense material by hot torsion tests, taking into account temperature and strain-rate sensitivity. Thus strain and thermal history are computed for material points lying on various flow lines during extrusion.

Numerical Simulation and Technical Study of Radiator Aluminum Extrusion

Numerical Simulation and Technical Study of Radiator Aluminum Extrusion

Numerical Simulation for the Cold Extrusion Process of the Worm Wheel Blank

The development of worm gear wheel blanks cold extrusion forming technology which can both reduce the manufacturing costs of the worm gear and enhance the Market competitiveness of products .Numerical simulation of cold extrusion forming technology of wheel blank was built by using Qform3D forging simulation software. That is, after the quantitative analysis of the distribution of stress fields and strain fields in the forming technology, determining the technology plan and conducting technology test, then the reasonable and feasible technology is designed. Cold extrusion can avoid the presence of the air gap, shrinkage and other tissue defects in the casting process, meanwhile raw materials can be saved 47% approximately than cutting.

Numerical Simulations of Middle-high Viscous Magma Extrusion by Means of Discrete Element Modeling

Numerical Simulations of Middle-high Viscous Magma Extrusion by Means of Discrete Element Modeling

Simulation of the Equal-Channel Angular Extrusion of Porous Blanks using Different Deformation Patterns

The results from simulation of equal-channel angular extrusion of sintered porous blanks with use of different deformation patterns are presented. It is shown that the maximum equidensity and the minimum volume of the poorly compacted area are observed in the pattern with a movable bottom plate of the die horizontal channel and with backpressure on the sample portion being extruded. This deformation pattern is also determined by the maximum values of deformation force.

FEM Simulation on Extrusion of Magnesium Alloys

Extrusion of magnesium billets is associated with large deformations, high strain rates and high temperatures, which results in computationally challenging problems in process simulation. A simulation was carried out using the finite element software ABAQUS. The computed model was rotational symmetric and built up by meshing. Computed parameters including material characteristics and process conditions (billet temperature. reduction ratio, and ram speed) were taken into consideration. The distributions of temperature were different comparing the transient-state extrusion with the steady-state extrusion. The extrusion simulation was the reliable predictions of strain rate, effective strains, effective stresses and metal flow velocity in an AZ31 billet during direct extrusion.

FEM Simulation Comparisons of Backward Extrusion

This study with constant shear friction uses DEFORM 2D software to perform FEM simulation of backward extrusion, and compares to SUPERFORM FEM simulation to realize the variations of forming conditions with the punch force and the final cup height. Effects of frictional factor, punch nose face angle, punch nose radius, and punch seizing length on equivalent stress, equivalent strain, velocity field, punch force, and deformed shape can be explored. Meanwhile using both FEM softwares to simulate can realize variations of both models in order to provide the reference of backward extrusion.

Numerical Simulation for Cold Extrusion of Bevel Gear

A three-layers assembled cavity die and its technological measures were designed for cold extrusion forming for the bevel gear. Numerical simulation of the cold extrusion forming process was applied using Deform-3D software, load curve, velocity field, stress field and temperature field were analyzed, thus obtain the basic knowledge of the law of the bevel gear deformation. Subsequent targets for optimization were introduced, aiming to solve the remaining problems of the current cold extrusion forming. The accomplished work shows some significance in guiding how to design a die and its technological measures.

The Model for Coupled Simulation of Thin Profile Extrusion

The paper presents the latest development of the numerical model for extrusion of industrial profiles having complex shapes. The model provides the material flow analysis coupled with mechanical and thermal problems in the tooling set. The simulation predicts possible shape deterioration due to uneven material flow through the bearing zone and helps to equalise it by means of optimisation of the bearing design, chamber and feeding channels. The locations of welding zones in the die are clearly predicted. It allows to modify the die design for better welding conditions and to provide optimal location of welding seams in the product. Die stress analysis shows the ways to extend the tool life by means of reducing of fatigue failure and selecting proper die materials as well as to correct the influence of the die deformation on the material flow. The described model is implemented in an especially dedicated program QForm-Extrusion that effectively simulates the extrusion of hollow and solid profiles with very high elongation ratios. The experimental verification of the model is illustrated by model and industrial experiments as well as by series of case studies performed in production environment.

Mesh Reconstruction Technology of Welding Process in 3D FEM Simulation of Porthole Extrusion and Its Application

For extrusion of hollow profile with asymmetric cross-section, existing FEM software cannot simulate the influence of divergent and welding on the metal flowing behaviors, because it is inability to deal with meshes separation and penetration during welding. A mesh-reconstruction technology based on the reverse engineering is proposed in this paper, and extrusions of Al-alloy hollow profiles with various cross-sections are simulated. The results show that the mesh-reconstruction technology can solve the problem of simulation termination caused by the meshes separation and penetration during porthole die extrusion. It is effective to analyze the metal flowing behaviors, temperature distribution, hydrostatic stress in weld-chamber, and stress on dies, which provides a practicable way for die structure design and optimization of porthole extrusion as well as quality forecast of extrusion products.