Groundbreaking experimental extrusion process and die mechanics such as metal flow simulation; thermo-mechanical modeling; FEM modeling; process development, optimization and control; research.

ET Technical Papers are Subject to Copyright
Papers published by the Extrusion Technology for Aluminum Profiles Foundation ("ET Foundation") in The Proceedings of the ET Seminar are subject to copyright. No part of The Proceedings, including individual papers submitted by authors for The Proceedings, may be reproduced in any form without the express written permission of the ET Foundation.

Extrusion Die R&D (RD) Track

RD329 - Factors Affecting 3-D Deformation Behavior of Automotive Extrusions

Warren Poole and Sheida Nikkhah, The University of British Columbia; K. Cheong and C. Butcher, University of Waterloo; and Nick C. Parson, Rio Tinto Aluminium, Canada
The use of medium-strength AA6xxx-series extrusions continues to grow in automotive structural and energy absorption applications, e.g., bumpers, rockers, and roof rails. The material requires sufficient ductility to undergo often complex 3-D deformation applied during part forming, joining and in crash. Material properties are typically measured in the longitudinal direction. However, extrusions can exhibit plastic anisotropy such that strength and ductility vary with the orientation of the applied load. Through thickness variations in microstructure, inherent in extrusions, also influence deformation behavior. To optimize performance, it is necessary to understand a material’s behavior at this level of detail. This study used tensile and bend testing to assess the behavior of recrystallized and non-recrystallized materials as a function of test direction. For un-recrystallized materials, the role of the peripheral coarse grain (PCG) layer was assessed, including tests where it was removed on one side of the profile by chemical etching.

RD330 - Effect of Local Microstructure on Mechanical Behavior of Extrusion Weld Seams

Andrew Zang and Warren Poole, The University of British Columbia; Jean-François Béland, National Research Council Canada; Yu Wang and Mary Wells, University of Waterloo; and Nick C. Parson, Rio Tinto - Aluminium, Canada

Hollow extrusions fabricated using porthole dies are widely used in automotive structures and crash applications. It is recognized that the presence of a bridge modifies the local microstructure at the weld seam, and it is important to understand how this region responds to complex plastic deformation applied during part forming and crush.  Model dies were used to produce an AA6082 strip with a central weld line. Microstructures were quantified using electron backscatter diffraction (EBSD). Variations in crystallographic texture were identified at the weld seam and used as inputs to predict local stress-strain response with the polycrystal crystal plasticity code, VPSC.  A finite element (FE) model was built to examine the response to loading perpendicular to the weld seam.  The predictions were compared with local plastic strain variations measured by "micro-scale" digital image correlation based on second phase particles.  Good agreement was obtained between the modeling results and the experimental measurements.

RD331 - Predicting Texture and Mechanical Properties of Al-Mg-Si Extrusions through Crystal Plasticity and Continuum Mechanics

Jean-François Béland, National Research Council Canada; Clément Pot, Quentin Boyadjian and Phillippe Bocher, École de technologie supérieure; and Nick C. Parson, Rio Tinto - Aluminium, Canada

The prediction of crystallographic texture and evaluation of related mechanical properties in Al-Mg-Si extrusions can be a valuable tool for optimizing die design, material processing and product performance at a macro and even microscale level. While not commonly used in aluminum extrusion processing, this technique is widely employed in the rolling industry to understand the relationship between process parameters and the resulting texture and mechanical properties. In this study, the FC-Taylor model is used to predict non-recrystallized texture from AA6082 extrusion simulations, employing continuum mechanics to evaluate mechanical properties from the predicted crystallographic orientations. The technique's accuracy is tested against experimental results for a specific extrusion profile.

RD342 - Production of Aluminum-Polymer Composites by Hot Extrusion

Patrick Kotzyba, Johannes Gebhard, and A. Erman Tekkaya, Institute of Forming Technology and Lightweight Components, TU Dortmund University; Enno Henn, Leibniz-Institute of Polymer Research Dresden; Markus Stommel, Leibniz-Institute of Polymer Research Dresden, Institute of Material Science, Technical University Dresden, Germany

The combination of aluminum and polymer has the advantages of lightweight design, damping and insulation. In an intrinsic co-extrusion process, aluminum hot extrusion and polymer extrusion is combined. The polymer melt is injected into the material flow of the aluminum at the weld chamber of a modified porthole die. Regarding pressure and weld chamber length, the process windows of aluminum and polymer extrusion vary significantly. The process parameters polymer melt pressure and weld chamber length are investigated experimentally with the objective to enable a stable co-extrusion process, with constant or specifically graded cross sections. Exceeding the process window can result in bursting profiles or leakage of polymer. With the chosen material combination of AA6060 and polyethersulfone, co-extrusion experiments are performed successfully and continuous hybrid profiles with a polymer core and aluminum shell are produced.

RD350 - Extrusion Behavior of the Bimetal Billet for AA6000 Series

Onder Ayer, Trakya University; Ismail Karakaya, eksenAL; Aybars Guven, TRI Metalurji A.S., Turkey

Aluminum alloys are ideal materials because of high specific strength, recycling ability, corrosion resistance, and especially low density for lightweight structures in the transportation, automotive, and aerospace industries. Hot extrusion offers to obtain a variety of aluminum alloy profiles with high productivity. For complicated profiles, welding problems could occur during direct extrusion. Products for special purposes require differences compared to conventional engineering materials. In this study, it is aimed to combine two different aluminum alloys in the same product. Therefore, a study was carried out in which a product was obtained using the direct extrusion process from a bimetal billet composed of two selected 6xxx-series aluminum alloys. Welding quality for the cross-section, changes in the mechanical properties, and material flow in the extruded product were investigated.

RD352 - Additive Manufacturing Technology Used for Extrusion Dies

Rolf Beckert, Ralf Huber and Joachim Maier, WEFA Inotec GmbH; Christoph Doerr and Nicolas Haydt, Trumpf Laser- und Systemtechnik GmbH; Maik Schiffmann, Armin Wiedenegger and Johannes Bruckwilder, voestalpine Additive Manufacturing Center GmbH; and Udo Danner, voestalpine High Performance Metals Deutschland GmbH, Germany

Certain aluminum alloys as well as special profile shapes require active nitrogen cooling during the extrusion process to ensure better productivity and material performance. New production methods like additive manufacturing (AM) offer to design cooling channels inside an extrusion die following the contour of the die bearing. With this new design-freedom, the implementation of a sufficient design with a data driven approach by taking the mechanical loads into account is needed to gain optimal results. First trials already show that AM production method is suitable also for tool steel applications producing extrusion dies for aluminum profiles with water cooling channels.

New AM production methods and machine technology allow even finer structures during the AM printing process. Together with the new developed powder-steel types like "Dievar" printed on a hot chamber metal 3D printer, this paper shows the results of an AM-manufactured extrusion die for a typical aluminum profile which is currently running in serial production. The effect of these implemented tailor-made cooling channels, its influence on productivity as well as the cost perspective of producing the die are discussed.

A comparison of the surface finish of the AM-manufactured extrusion die in production is performed and the differences in extrusion results are shown. Thus, two extrusion dies are manufactured, whereas the first die is treated after the AM process additionally with the standard die making process to guarantee standard appearance of the surface of the die and the profile. Within the second die, the majority of the surfaces shall be left as they are directly after the AM process.

RD356 - Influence of Test Parameters on Intergranular Corrosion (IGC) Test Results (ISO 11846 Method B)

Jan Tore Gundersen, Malgorzata Chojak Halseid, Helge Eskild Steensen, Hege Rullestad Wathne and Odd Inge Finne, Hydro Aluminium Metal R&D, Norway

The test method described in ISO 11846 Method B is one of the most popular test methods to study the susceptibility of 6xxx-series alloys to IGC. This standard allows for a significant variation in several testing parameters such as the ratio of the test solution volume to the total specimen area and the test solution temperature.  The test solution volume to the total specimen area is influencing the pH of the electrolyte (corrosivity of the solution changes with time) while higher temperature will affect corrosion morphology. For alloy 6005 the difference in corrosion depth could be even 50%, depending on the test parameters. This work shows that understanding the influence of the test parameters is important to ensure a more accurate comparison of the IGC resistance of the alloys tested.

RD367 - Critical Evaluation of Different Simulation Scenarios of Semi-Hollow Dies

Lasindu Gayashan, Praveen Chathuranga, Tharindu P. Induruwa, Waruna Sandaruwan, and Danusha S. Wijethilake, Alumex PLC, Sri Lanka

The use of FEA simulation is widespread in various industrial sectors, including the extrusion industry, which employs simulation of die design. Simulation in all fields is greatly influenced by boundary conditions. Its impact in specific cases should be analyzed individually. Semi-hollow dies are used to create partially enclosed shapes, and they contain a mandrel similar to hollow dies, but do not produce complete voids. The die plate seats with the core along the neck of the tongue, and tends to deflect with the applied load, similar to hollow dies. In the simulation process, the seating area is fixed to avoid meshing errors. Although the die is optimized based on simulation results using fixed-edge boundary conditions, real-world results deviate significantly from expectations. This paper discusses the identified deviation and assesses the fixed edge method, conventional hollow type and other possible solutions to determine the best simulation approach for semi-hollow extrusion dies.

RD380 - Local Foaming of Extruded 6082 Hybrid Profiles by Means of an Adapted T6 Heat Treatment

Florian P. Schäfke, Christian Klose, Germany and Hans Jürgen Maier, Institut für Werkstoffkunde (Materials Science), Liebniz University

Compared to compact solid material, cellular structured metals offer both higher specific strengths and stiffnesses, as well as higher energy absorption and damping capacities due to their low densities. The powder metallurgical process route is used to produce the precursor materials for the closed-pore foam structures. In the current process, EN AW-6082 metal powder is mixed with a metal hydride powder as a blowing agent and compacted to form a semi-finished product. This semi-finished product is combined with the solid aluminum alloy EN AW-6082 to form a multi-material billet consisting of a core material and a shell material and processed by direct extrusion. Depending on the arrangement of the foamable and solid components, local foaming in predefined areas is enabled. The extruded hybrid profile is subjected to an adapted T6 heat treatment so that decomposition of the blowing agent occurs, and a local cellular structure is formed.

RD385 - How Artificial Intelligence (AI) Supports the Production of High-Precision Aluminum Extrusion Dies

Ralf Huber and Joachim Maier, Wefa Inotec GmbH; Yexu Zhou and Till Riedel, Karlsruher Institut für Technologie, Germany

The demand for low-weight aluminum constructions leads to a new approach on how to produce aluminum extrusion dies. Downsizing of profile dimensions are challenges for the capability to produce extrusion dies with smallest tolerances and repeatability. Requests of web walls below 0.15mm and tolerance of +/-0.02mm are the new targets. Machine and process parameters are collected, and all information will be combined and summarized within a "big data" database. In cooperation with the Karlsruhe Institute of Technology (KIT), software has been developed to analyze the data by using artificial intelligence (AI). All parameters can be investigated in terms of signification and correlation. In examples it will be shown how the impact of temperatures, machine parameter and die dimensions are analyzed by AI and will support the optimization of high-precision extrusion die production.

RD391 - A Virtual Extrusion Test for Rapid Evaluation of Extrudability of 6xxx-Series Aluminum Profiles

Mads Iddberg, SINTEF Manufacturing; Ole R. Myhr, Hydro Aluminium R&D and NTNU; Anders Nesse, Hydro Extrusions; and Trond Furu, Norsk Hydro, Corporate Technology Office and NTNU, Norway

The present article presents a virtual extrusion test based on simulations. The virtual test is developed to quickly evaluate the extrudability of 6xxx-series extrusions where alloy composition, casting conditions, and the homogenization cycle are required inputs to predict the maximum extrusion speed before hot tearing occurs. The virtual extrusion test is valid for rod-shaped profiles and some standard single and multi-cavity hollow profiles where analytical solutions for the exit temperature at the die outlet have been developed. For generic profile geometries, the virtual extrusion test requires FE-simulations as a basis for the extrudability predictions. The calculated temperatures and extrusion speeds have been compared with measurements from extrusion tests of various 6xxx-series alloys. The comparisons indicate that the presented modeling approach gives sufficiently accurate predictions for future application in optimization of alloy composition and process parameters in extrusion of 6xxx-series alloys.

RD394 - Machine Learning: The Emerging and Powerful Tool for Material and Process Development and Optimization

Nhon Vo, Ha Bui, and Andrew Halonen, Amatrium Inc.; and Nhon Vo, NanoAL LLC, USA

Alloy and process optimization in the metal industry, starting with trial-and-error, has advanced significantly, thanks to multi-scale computer simulations and high-throughput experiments. Recently, with a vast amount of data generated from modern production equipment and the advancement of the machine learning field, a powerful tool for alloy and process optimization has emerged. In this paper, we demonstrate how a particular machine learning program is embedded in the traditional alloy development workflow to shorten the timeline, eliminate unnecessary experiments, and save costs. An explanation is presented for how this program can be utilized to improve product quality by having the ability to better control chemistry and process in metal production flows. Lastly, the use of machine learning is outlined in preventive maintenance for expensive production equipment, which could significantly save costs from downtime.

RD397 - Using DSC Thermal Analysis for Understanding the Quench Effect on the Microstructure of EN AW-6082 Aluminum Alloys

Emrah F. Ozdogru, Aybars Guven, Isik Kaya, and Aleyna Gumussoy, TRI Metalurji A.S., Turkey

Differential Scanning Calorimetry (DSC) and other thermal analysis methods have been applied extensively to aluminum alloys for determining solid-state reactions such as precipitation and homogenization, and solid-liquid reaction such as incipient melting and solidification. EN AW 6082 aluminum alloys are very common in high mechanical properties required areas such as automotive and railway (rolling stock) industries. To reach the required mechanical properties, the quenching properties of the alloy were analyzed in detail. In this paper, by using DSC thermal analysis method, different heat cycles (heating and controlled cooling-quenching) were applied to the commercial EN AW 6082 aluminum alloy to identify the precipitation sequences, in continue, the same cooling rate is also applied to the sample for analyzing the microstructure evaluation. The outcomes have explained that DSC data could help in understanding the peaks of temperatures for precipitation, as well as microstructure formation after quenching test for sample.

RD400 - Dummy Block Evolution; Design Optimization for High-Pressure Extrusion

Yahya Mahmoodkhani and Paul Robbins, Castool Tooling Systems, Canada

To increase productivity, many new press manufacturers have significantly increased the dummy block face pressure to enable structural alloys to be extruded at acceptable speeds. The dummy blocks must be able to tolerate the higher pressures and at the same time expand to a desired diameter to control the gap between dummy block and container liner. The challenge is to have the dummy block expand and collapse repeatedly to near nominal diameter. Most extruders expect 20,000 or more cycles. To achieve this goal, the plastic deformation of the ring should be avoided by proper and accurate design. Using simulation tools is a key element to design such a dummy block. In this paper, dummy blocks designed for different face pressures are reviewed. The finite element method is used to simulate the deformations and model predicted results are analyzed to optimize the design. A detailed review of the High-Pressure Ring (HPR) Dummy Block is provided. This block is developed and optimized for modern extrusion presses with short stroke, high pressure, long billet, rapid acceleration, and long cycle time. A brief overview of material selection, heat treatment, surface treatment and lubrication of dummy block are also discussed.

RD412 - Influence of Quench-Rate and Artificial Aging Parameters on the Cracking of C20 Crash Alloy TRIMAL-54 during Uniaxial Compression Testing

Axel Marquardt, Tobias Beyer, Luisa Marzoli, and Marcel Rosefort, TRIMET Aluminium SE, Germany

As CO2 reduction in transportation gains momentum, specialized materials for lightweight and energy-efficient construction are of increasing interest. Aluminum alloys of the 6xxx-series are highly suitable candidates for nearly all automotive applications. They provide a good balance between high strength and ductility, while having good corrosion resistance. In this paper, Trimal-54 by TRIMET Aluminium SE, Essen, Germany, is characterized for the influence of quench-rate, and subsequent artificial aging on its cracking behavior during uniaxial compression testing. Specimens are extruded at different speeds and quenched in air or water. All specimens are aged to T7-temper and then mechanically tested.
The link between observed tensile strength in uniaxial pull and mechanical properties during uniaxial compression is investigated. In addition, microstructural features identified by optical and electron microscopy are correlated to findings during those compression tests.

RD416 - Aluminum Tubing with Locally Modified Properties by Shear Assisted Processing and Extrusion (ShAPE)

Mageshwari Komarasamy, Brandon S. Taysom, Brian Milligan, Benjamin Schuessler, Glenn Grant, Darrell Herling, and Scott Whalen, Pacific Northwest National Laboratory (PNNL), USA

Shear Assisted Processing and Extrusion (ShAPE) is an emerging technology that rotates the die or billet during pressing to impart severe plastic deformation into the microstructure. A unique aspect of ShAPE is the ability to locally modify material properties along the extrusion length by changing temperature and strain. This work reports progress toward creating tubes (AA6111) and rolled strip (AA5182) with local variations in strength and elongation. A 25% and 60% difference in toughness was achieved for 6111 and 5182, respectively, with a transition length of approximately 50mm. Microstructural characterization is provided to explain the property variations. A technique is presented for actively modifying the wall thickness of round tubing during indirect extrusion. AA6061 tubing with 20mm outer diameter was extruded with wall thickness ranging from 1-3mm using an articulating tapered mandrel to vary stiffness along the length of the extrudates.

RD449 - Physical and Numerical Modeling of Microstructure Evolution and Micro-Extrusion during Solid-State Recycling of Aluminum Alloys

Mahsa Navidirad, Natasha Vermaak, Masashi Watanabe, and Wojciech Z. Misiolek, Loewy Institute, Lehigh University, USA

The long-term goal of the presented project is to develop an industrial process in which the machining aluminum chips are consolidated and extruded into products with superior mechanical properties. To better observe the metal flow phenomenon, aluminum chips are "upgraded" to strips, which are deliberately covered by a thick colored oxide film through the anodizing process. The coated aluminum strip sandwiches are then cold rolled at different reductions per pass, ranging from 2% to 80%.  The objective of the presented study is to analyze the metal flow and to understand the joining mechanisms taking place at the interface of the machining chips under deformation conditions. Scanning electron microscopy (SEM) imaging and Electron Backscatter Diffraction (EBSD) techniques are utilized to measure the height of micro-extrusions through the fragmented strips’ surface oxides and the grain microstructure. A DEFORMTM software is also used to develop a numerical model for predicting micro-extrusion behavior.

RD457 - Comprehensive Numerical Simulation of the Quenching Process in Aluminum Profile Extrusion

Ivan Kniazkin, Nikolay Biba, Vladimir Krylov, Ivan Kulakov, and Andrei Shitikov, Micas Simulations Limited, United Kingdom; and Tom Ellinghausen, Forge Technology, Inc., USA

To produce extrusions with minimal distortion, desired mechanical properties (tensile strength and hardness), and to determine the appropriate cooling rate, the QForm UK team has developed a module that integrates with extrusion simulation and allows the user to design the optimal quenching process. It accurately calculates the temperature evolution and profile deformation based on the 3D motion of the cooling environment. The effect of the puller on profile distortion and twisting is also taken into account.

Analysis of the quenching process is critical for extruders and for tool designers, since the die design itself plays an important role in development of thermal distribution throughout the extrusion process that will affect the quenching system setup. Various quenching methods, including forced air cooling, fan cooling, water mist cooling, and water spray cooling are available in simulation to cover industrial needs.

RD467 - Development of a Parameterized Model for Additively Manufactured Dies to Control the Strains in Extrudates

Fabian Esterl and Noomane Ben Khalifa, Institute for Production Technology and Systems, Leuphana Universität Lüneburg; Maria Nienaber, Jan Bohlen and Noomane Ben Khalifa, Institute of Material and Process Design, Helmholtz-Zentrum Hereon, Germany

The anisotropy of materials often restricts the wide application of flat products and profiles. During conventional extrusion, the direction-dependent material flow results in the formation of a strong crystallographic orientation, which causes anisotropic mechanical properties. Additive manufacturing of dies offers the possibility to alter the material flow and thus influence the material properties. Hereby the state variables must be considered by influencing the material flow. Therefore, this study aims to develop and verify a parameterized model that contributes to the understanding of the material flow and strain path during hot extrusion. The knowledge gained is important for optimizing the die geometry and process parameters to allow controlled development of crystallographic orientation and thereby to reduce the anisotropy by extrusion.

RD469 - Flow Behavior Investigation during Miniaturized Extrusion of Aluminum (AA6082) and Magnesium (AZ31)

Maria Nienaber, Jan Bohlen and Noomane Ben Khalifa, Helmholtz-Zentrum Hereon; Fabian Esterl, Jonas Lehmann and Noomane Ben Khalifa, Leuphana Universität Lüneburg, Germany 

A strong crystallographic texture is often formed during aluminum extrusion, with a distinct orientation of the basal planes. This microstructural evolution plays an important role in defining the extrudate mechanical properties like anisotropic behavior, which may be tolerable in some cases but undesirable in others. The presented work aims to determine the adjustable key elements that govern material flow during aluminum extrusion. The overall objective is to control extruded product texture development by controlling process parameters and die design. In this context, extrusion experiments are conducted using die designs of round and rectangular aluminum profiles with the variation of extrusion speed and initial temperature. Consequently, the billet rest and the extrudate are examined to characterize the nature and intensity of relations between the varied parameters and material flow. Parallel to the experiments, finite elements models of the experiment setups are created, validated, and further used to expand the experimental investigation.

RD473 - An Alloy Design Approach to Maximize Processability of High Recycled Content 6xxx-Series Alloys

Alex Poznak and Jeff Victor, Hydro Innovation & Technology, USA; Anders Nesse, Hydro Extrusions, Norway; Thomas Korejsza, University of Michigan; and Adam Hope, Thermo-Calc Software Inc., USA

Recycling represents one of the most viable techniques to lower the carbon footprint of aluminum production.  However, alloys made from high amounts of scrap typically contain higher impurity levels, which can have a negative impact on both extrudability and final properties.  The impact of Fe impurity level in AA6061 alloys is examined using Thermo-Calc and Python.  Over 240,000 compositions are simulated, which span the entire AA6061 composition range for silicon, iron, copper, manganese, magnesium, and chromium.  Key metallurgical metrics such as Mg2Si solvus and solidus temperatures are discussed.  Emphasis is placed on the relative stabilities of detrimental (β-AlFeSi) and preferred (α-Al(Fe,Mn,Cr)Si) intermetallic particles, because their amounts are well known to impact hot ductility and extrudability.  Results show that elevated levels of Fe require higher homogenization temperatures to maximize extrudability, and in some cases require impossibly small processing windows.  However, compositional adjustments can be made to reduce this effect.

RD474 - Overview of Methods to Evaluate Extruded Profile Ductility as It Relates to Automotive Profiles

Jeff Victor, Alex Poznak, Lucas Itchue, Hydro Innovation & Technology; and Mike Tozier, Hydro Extrusion USA LLC, USA

Aluminum extrusions are used for a variety of automotive applications. Many designs have ductility requirements that extend beyond what can be determined from a tensile test. Methods to measure and quantify ductility are reviewed, including tensile reduction in area, coupon bend testing, component axial and transverse crush testing, and component three-point bend testing. The type of data generated, interpretation of the results, and guidelines for using each method are reviewed. There is no single best method but linking the design requirements to the test method can reduce risk. It is important to distinguish tests that monitor the process versus evaluating performance of a part. When processes and products are well understood, surrogate tests including reduction in area and coupon bend tests can be sufficient for lot release. Highly critical parts, parts with complex load cases, or processes with insufficient characterization may require components tests linked directly to performance.

RD475 - Industrial Implementation of Simulation-Based Tool Design to Ensure High-Quality Seam Welds in 6082 Automotive Profiles

Ivan Kulakov, Ivan Kniazkin and Nikolay Biba, Micas Simulations Limited, United Kingdom; Abdelilah El Oirzadi and Brambilla Moreno, PHOENIX International S.p.A., Italy; Sara Di Donato and Lorenzo Donati, DIN – Department of Industrial Engineering – University of Bologna; Riccardo Ruggieri, Massimiliano Margutti, and Alberto Terenzi, Hydro Extrusion Italy s.r.l.; Barbara Reggiani and Riccardo Pelaccia, DISMI – Department of Sciences and Methods for Engineering – University of Modena and Reggio Emilia (and) InterMech – MO.RE University of Modena and Reggio Emilia; and Marco Negozio, University of Parma – Department of Engineering and Architecture, Italy

Achieving high-quality welding seams when using porthole dies for aluminum profile extrusion is a critical challenge. Industrial extruders have shown a growing interest in utilizing digital twin technology to optimize tool design and process parameters to achieve highly deformable and robust seam welds while reducing the need for time-consuming and expensive experimental trials. The main objective of this work is to demonstrate the capabilities of the dedicated seam weld quality tool within the QForm UK extrusion software environment for the numerical optimization of AA6082 aluminum alloy extruded profiles. The tool considers all critical aspects that affect seam weld integrity, making it a reliable solution for achieving high-quality welding. A group of experts in different areas of the extrusion technology field collaborate in this work, contributing to the development and manufacturing of the extrusion tool set and industrial validation of the seam weld quality.

RD484 - The Influence of Alloy Characterization Approaches on Extrusion Process FEM Simulation Reliability

Sara Di Donato and Lorenzo Donati, DIN Department of Industrial Engineering - University of Bologna; Riccardo Pelaccia and Barbara Reggiani, DISMI Department of Sciences and Methods for Engineering – University of Modena and Reggio Emilia (and) InterMech – MO.RE – University of Modena and Reggio Emilia; and Marco Negozio, University of Parma – Department of Engineering and Architecture, Italy

FEM Codes are widely used by extruders and die makers for design and process optimization. In order to perform reliable simulations, it is mandatory to include an accurate modeling of the material flow stress. In this context, the Hansel-Spittel law represents an accurate strain-dependent model for predicting material behavior not only for hardening, but also for softening occurring at high temperatures. Nevertheless, the limitation of the H-S relationship is the lack of experimental data and model parameters available in literature for different materials. In this work, the H-S parameters for different aluminum alloys were calculated based on the results obtained from the hot torsion tests available in the laboratory of the University of Bologna. The hot torsion test can be carried out with constant speeds and temperatures reaching large strain values, thus providing a reliable set of data for the numerical regression and the optimization of the Hansel-Spittel parameters.

RD487 - A Methodology for the Development of AA6063 Recrystallization Model using FEM Simulation

Marco Negozio, University of Parma – Department of Engineering and Architecture, Italy; Antonio Segatori, Hydro, Innovation and Technology, Sweden; Riccardo Pelaccia and Barbara Reggiani, DISMI Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia (and) DIN Department of Industrial Engineering – University of Modena and Reggio Emilia; Sara Di Donato and Lorenzo Donati, DIN Department of Industrial Engineering – University of Bologna, Italy

The microstructure of lightweight alloys affects mechanical, crash, corrosion, and aesthetic properties of extruded profiles. Research activities are needed to investigate the correlation between processing parameters and grain structure of the final components for each specific alloy. In this context, experimental investigations of the microstructural evolution in different industrial-scale AA6063 extruded profiles are carried out. A novel modeling for the dynamic (DRX) and static (SRX) recrystallization behavior of 6xxx-series aluminum alloy is developed, optimized for simulation of the AA6063 recrystallization behavior and implemented within the commercial FEM code QForm UK Extrusion. The results of DRX-SRX simulations are further validated on various cases of different scale and extrusion ratio. The aim of this work is to propose, optimize and validate a reliable methodology for the microstructure prediction and the final grain size distribution in the extrusion of AA6xxx-series aluminum alloy profiles.

RD488 - A Novel Analytical Formula for Charge Weld Extent Prediction

Riccardo Pelaccia, A. Ricucci and Barbara Reggiani, DISMI Department of Sciences and Methods for Engineering – University of Modena and Reggio Emilia; Marco Negozio, Sara Di Donato and Lorenzo Donati, DIN Department of Industrial Engineering – University of Bologna; and Tomasso Pinter, Almax-Mori, Italy

The scrap derived from the charge welds defect is a relevant cost that shall be limited. In addition, the risk of discarding defect-free profile lengths or, on the opposite, selling components with low mechanical properties need to be avoided. Recently, the potential of using numerical tools has been proved for predicting the charge welds extent. However, simulations may require many hours of computation, not always well-matched with industrial times. Interest then emerges for a faster analytical approach to accurately predict the charge weld extent based on the main involved process and die parameters. The aim of the work is to propose a novel empirical formula that overcomes the limitations of those available in literature that can return errors up to 30% in terms of scrap extent evaluation. Many experimental and numerical data collected on industrial profiles are analyzed to calibrate and validate the novel formula.

RD491 - Simulating the Aluminum Extrusion Process with a Coupled Meshfree and Finite Element Method

Kirk Fraser and Jean-François Béland, National Research Council Canada; and Rémy Bretin, École de technologie supérieure, Canada

Aluminum extrusion process simulation is a useful tool for predicting and optimizing the process performance.  Commercial simulation software typically employs an eulerian approach to approximate the process being at steady-state, and some transient solutions are available with arbitrary lagrangian-eulerian (ALE) and updated lagrangian methods.  A new approach for simulating the aluminum extrusion process is presented, combining the meshless smooth particle hydrodynamics (SPH) method with the finite element method (FEM).  The combination of these two methods offers a fully transient, highly non-linear lagrangian approach that allows capturing the die elastic deformation and the complex mechanical behavior of the aluminum at the same time.  This coupled SPH-FEM method is computed using graphics processing units (GPUs), which greatly improves its efficiency.  This paper provides an overview of this simulation method, demonstrates its potential as a valuable tool for the optimization and control of aluminum extrusion processes, and presents some results compared to experiments.

RD505 - Effect of Mg and Si Concentration on Hot Deformation of AA6082

Eli A. Harma and Paul G. Sanders, Michigan Technological University, USA

Within the AA6082 specification range, it may be possible to find a composition that would increase the extrusion rate. The dynamic recovery activation energy, which is a function of Mg and Si, affects the extrusion rate. To quantify the effect, Mg and Si are varied for a 6082 alloy with a constant concentration of Mn, Cr, and Fe at a single homogenization treatment. Hot compression and/or torsion testing at 450°C-550°C and 0.01 - 4s-1 strain rate over a range of compositions is fit to the hyperbolic sine law to quantify the dynamic recovery activation energy. The average grain misorientation and fractions of dynamically recovered and recrystallized grains are assessed with Electron Backscatter Diffraction (EBSD). It is anticipated that lower Mg and Si content will decrease the dynamic recovery activation energy leading to lower high-temperature flow stress and faster extrusion speeds.

RD535 - Charge Weld Prediction in Hollow Aluminum Extrusion

Eren Can Sariyarioglu, Torgeir Welo and Jun Ma, Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology, Norway; Marco Negozio, Department of Engineering and Architecture, University of Parma, Italy

Charge welds occur in billet-to-billet extrusion due to the transition between successive billets, potentially leading to degradation of mechanical integrity and considerable in-process scrap in industrial practice.  Accurately predicting charge weld formation is crucial to the carbon footprint while improving quality of extruded products. This paper aims to investigate the predictability of charge weld evolution in AA6060 hollow extrusion using numerical and analytical approaches. Numerous industrial, full-scale extrusion experiments were conducted to characterize charge weld formation. A finite element (FE) model was developed to predict the charge weld evolution in terms of cross-sectional and longitudinal locations. In addition, industrial type rule-of-thumb models were employed for comparison purposes. FE model is capable of providing significantly more accurate prediction of charge weld ‘scrap length’ than analytical methods in terms of reproducing the distribution across the profile’s cross section. Overall, the findings provide practical guidance for more effective assessment and analysis of charge weld development in aluminum extrusion practice.