EP165
Microstructure Effects on Damage Evolution in Aluminum Weld Seams Studied through X-Ray Computer Tomography

EP029

Long-Term Wear Investigation on CVD Coated Extrusion Dies

Joachim Maier, Rolf Beckert and Thuy-Vu TranWEFA Singen GmbH, Germany

With a new Tribo Wear Tester, wear prediction for CVD coated dies, it is possible now to detect coated die wear under ”close-to-extrusion”-conditions. Under stable temperature control the set parameters rotational speed, pressure and probe temperature are used to verify different CVD coatings against certain Al-alloy combinations. The aim is to find the optimum conditions in order to create a critical value for coating wear to be end of life criteria. Standard High Temperature (HT)-CVD coating types for standard application and Medium-Temperature (MT)-CVD coating types for improved profile surface quality were included in the study. The long-term tribological test lifetime in meters was compared with real die coating failures in order to create a set-value. For the failure modes a classification chart was created. Besides abrasion phenomena the adhesion of various alloys to the coated extrusion die has an important impact mainly on profile surface quality. The adhesion effects were investigated in an adhesion test set-up and the relation between adhesion thickness and re-crystallization layers were discussed. Besides the light metal application, the adhesion and abrasion test methods are also applicable and can be extended for other materials like brass, silver, magnesium, zinc, etc. and also for other metal forming processes based on a coated tool substrate.

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EP034

Paying Attention to Details of Die Corrections and Process Control for High-Precision Extrusions

Mushtaq Mohammed, Suresh Annadurai, and Modar AlMekdad, Gulf Extrusions Co. LLC, UAE

Dies can be sourced from an experienced die manufacturer, prepared carefully by the die correction team, heated to the correct temperature and still not give the required results. Well-trained press operators and good process control in terms of billet temperature and extrusion speed are also essential. Paying attention to details for die correction while ordering the dies and controlling the process parameters is very important as billet temperatures cannot be changed quickly. Temperature gradients are difficult to control. Extruded sections with tight tolerances are difficult to produce if there are excessive temperature variations between successive billets. The ability to control the upset speed and pressure depends on the press control system. It is important to have a good understanding of how the pressure builds up at the start of extrusion and to know if this can be controlled by the operator. Presses need not have the necessary control of speed and pressure at the start of extrusion for complex extrusion. Extrusion is a complex process and a successful plant requires a well-trained work force to pay attention to the details of die correction, quality control and extrusion process parameters who understand the need for good working practices and process control.

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EP035

Research on Die Design to Overcome Weld Lines and Streak Lines in Anodized Profiles

Modar AlMekdad, Suresh Annadurai, and Mushtaq Mohammed, Gulf Extrusions Co. LLC, UAE

Today in the region of Middle East, customer demand for anodizing profiles has considerably increased compared to other surface finishes. Since there is a high volume of switch over from other finishes to anodizing finish, the quality demand towards surface quality of anodized profiles free from any surface defects such as weld/web lines and streak lines has increased substantially. The “APQP" (Advance Product Quality Planning) team was formed in order to resolve quality issues. The scope of the work covers the following subjects:

1. Relocation of web/ribs from the die design aspects
2. Reduction of webs/ribs in the die design
3. Increase in welding chamber
4. New die design concepts to overcome dead metal in the die to avoid streak lines
5. Simulation of die design prior to manufacture, comparison of actual extruded profiles and the results.

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EP036

Role of Die Shop Management to Enhance the Profitability of the Business

Modar AlMekdad, Suresh Annadurai, and Mushtaq Mohammed, Gulf Extrusions CO. LLC, UAE

The role of die shop management is vital in the extrusion industry. With proper die shop management, the efficiency of all the downstream processes can be increased considerably, which will result in savings for the organization. By having a proper control on the following aspects, die shop efficiency can be improved:

1. Focus on new profile inquiry handling, which includes accepting the profiles that are feasible to extrude with reasonable productivity and recovery
2. Focus on die designs in order to have minimum trials for new dies and zero trials for backup dies
3. Effective control on tool inventory and proper management of tooling.
4. Effective control on back-up die ordering policy by reviewing the performance of the existing die, existing order and forecast of future orders.
5. Reduction in die failures by having proper die design and appropriate correction approach.
6. Improving die life by optimizing Nitriding process at appropriate intervals.
   
   

The advantage of proper control on the above points will help in "on time order completion/ on time delivery," reduction in scrap/waste, improve productivity in extrusion, powder coating, anodizing and to achieve quality products, which results in customer satisfaction.

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EP046

Extrusions for Automotive Crash Applications

Nick Parson, Rio Tinto Aluminum, Canada; Jean-Franҫois Béland, National Research Council, Canada; and Jerome Fourmann, Rio Tinto Aluminum, USA

One of the main applications for extrusions in the automotive sector is crash structures, including crash rails, crash cans, bumpers and structural body components. The objective is usually to optimize the energy absorption capability for a given structure weight. The ability to extrude thin-wall multivoid extrusions contributes to this goal but the alloy used also plays a significant role in terms of the ability to produce the required geometry, strength which to a large extent controls the energy absorption capability and the ductility or fracture behavior which controls the strain that can be applied locally during crush deformation before cracking. This paper describes results of a test program to examine the crush behavior of a range of alloys supplied by Rio Tinto Alcan for automotive applications as a function of processing parameters, including artificial Aging and quench practices.

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EP048

Die Correction for Seam Weld Lines - A Non-Conventional Approach

Modar AlMekdad, Gulf Extrusions Co. LLC; Sutanay Parida, Taweelah Aluminium Extrusions Company (TALEX) LLC; and Suresh Annadurai, Gulf Extrusions Co. LLC, UAE

Seam weld (longitudinal weld) lines are a well-known problem in all anodized aluminum extrusion profiles. By relocating the weld chambers away from the exposed surface, the problem could be solved to a large extent. However, some profiles have almost all surfaces as exposed-surface. Many customers demand anodizing finish without any weld lines. Gulf Extrusion has taken up the issue as an R&D project and has been consistently working on this for the last three years. An obstruction (hump) created on the flow path of the die. By changing the geometry of the hump, flow pattern inside the ports could be changed. The impact of the changed-flow on the anodized surfaces is the main point of the studies. By observing the surface quality (weld-mark intensity) and shape vis-à-vis the changes incorporated on the hump, a limit could be set on the correction. At one extreme point of time, the shape becomes out of control, which defines the correction-limit. With a reverse engineering of recorded data, a best geometry of the hump could be established. This point is called a stabilized point. During the above experiment, extrusion parameters are made constant or changes made are recorded to create a relationship of its impact on the profile surface quality. Similarly, in anodizing all the parameters are kept at a constant value.

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EP060

Solving Vexing Tooling Issues with Villares VEX

Patricia Miller, Böhler Uddeholm Corporation, USA; Jeffrey Bourgoine, Mid-States Aluminum, USA; and José Britti Bacalhau, Villares Metals S.A., Brazil

Villares Metals along with Bohler Uddeholm Corporation introduced an entirely new grade of hot work tool steel to the aluminum extrusion tooling market at ET2012. This grade, called VEX, is a hot work tool developed to have superior hot wear and temper resistance over the traditional H13. It also responds to nitriding, a common practice with extrusion dies, with a deeper and harder case. This paper will discuss its capabilities, and actual production performance. It has been shown that in high extrusion ratio profiles, wear on the bearing surfaces has been significantly reduced, so that renitriding or servicing the dies has been minimized or eliminated over the total production run of the profile. Extrusion speed has been increased while maintaining a better wall uniformity. Throughput has increased to more than 20 percent. Therefore, from both a production and die life perspective, significant savings in costs have been experienced through the use of Villares VEX.

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EP081

Thermite Reactions during Extrusion of Aluminum

Oddvin Reiso, Hilde-Gunn Øverlie, Ulf Tundal, and Jostein Røyset, Hydro Aluminium Research and Technology Development (RTD), Norway

A newly discovered phenomenon during extrusion of aluminum may have a major impact on quality parameters during extrusion, namely the occurrence of thermite reactions. This is a reaction that takes place between the iron oxide layer on the bearing surface in the extrusion die and the aluminum that is extruded over it. The reaction is very exothermic and releases a huge amount of energy where the local temperatures may reach 2000°C, i.e. well above the melting temperature of the die steel (1536°C for Fe) and far above the melting temperature of aluminum (660°C). If such a violent reaction takes place it would be expected to cause severe damage to the surrounding materials. The present work focuses on documenting that a micro-scale thermite reaction does take place during extrusion of aluminum, as well as documenting some of the effects of such a reaction. It is shown to have a significant impact on factors such as profile surface quality and wear of the extrusion die.

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EP085

How to Benefit from Isothermal Extrusion: A Customer's View

Alexander Klaus , Constellium Extrusions Landau, Germany

Properly managing profile temperatures at press and quench exit is key to the extrusion process as they determine product quality. Isothermal extrusion is the target to ensure a stable, repeatable, high quality, and highly productive process. There are different ways to achieve this target, some of which are commonly used in the extrusion industry such as tapered billet heating, tapered container heating, or simple process control. Others like process simulation or advanced process control are still in development. This paper deals with industrial experience using commercially available temperature process control (TPC) provided by SAI/Williamson at four of Constellium's direct soft alloy presses for two years. In order to benefit most of the system purchased, it must be prepared and embedded with management, operators, databases, and organizational process. Early buy-in, quick ramp-up, and visible results are crucial for a successful installation. It is important to understand temperature-to-speed sensitivity of different products as this affects the way isothermal process control works as well as natural limitations to the control like measuring accuracy and draw backs like the virtual temperature increase, inherent to the measurement system. From the experience gained, cornerstones for profiting most from isothermal process control are presented.

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EP088

Surface Defects on 6463 Alloy Extrusions for Bright Dip Anodizing Finish

Hanif Hamzah, Press Metal, Malaysia

Various surface defects such as streaking, die lines, pitting, and backend defects and others are observed after the bright dip anodizing process using 6463 alloy. Comprehensive studies on polishing, mill conditions before anodizing, die design and extrusion practice has been analyzed. It was observed that the die design using pocket control for solid dies has a better recovery than ring type feeder design. The experimental results with these two types of die designs are carried out on a 5-inch press using 6463 alloy. The extrusions are later sent for bright-dip anodizing and the anodizing parameters are kept constant through the process. The results show that pocket control die design has a higher recovery as compared to others. Streaking lines are also reviewed through better die design of the bearing length and the shape of the pocket design. The streaking lines are also found coming from lubrications. Two different lubrications are used in the trials to demonstrate this defect and the results for the best recovery. The effect of billet composition, extrusion and anodizing practices also will be discussed. In conclusion, the best recovery for 6463 alloy depends on the better die design and good, well controlled operating practice.

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EP100

Controlled ZeroFlow® Gas Nitriding Increases Durability of Extrusion Dies

Karolina Ostrowska, Piotr Okoniewicz, Technical University Poznan, Poland, and Leszek Maldzinski, Technical University Poznan, Poland and Seco/Warwick Poland, USA

The aim of the tests conducted both in laboratory and industrial conditions was to increase the service life of the extrusion dies for hot extruding of aluminum profiles through ZeroFlow controlled gas nitriding. Wear mechanisms of the dies have been analyzed, stating that it occurs through the formation of cracks on the working surfaces due to thermo-mechanical fatigue, brittleness of the material as a result of growth of the above-mentioned cracks, frictional and chemical wear, breaking of internal elements of the dies. The reason for the rapid wear of many dies is improper, in terms of phase structure, thickness and hardness, and nitrided layer. It has been demonstrated that by the use of ZeroFlow controlled gas nitriding, developed by SECO/WARWICK Europe and the University of Technology Poznan/Poland, one can form permanent diffusion layers on the dies. In the operation conditions, the best, in terms of durability and economy of the nitriding process layer, should consist of the near-surface zone and the precipitation zone, not including the nitride network on the grain boundaries and in the corners of friction pieces. After wear of the layer the dies can be nitrided again several times.

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EP102

Die Description Data (DDD) - New Open Common Format Suggestion for the Aluminum Extrusion Industry

Sinan Akyar and Mehmet Akyar, MIP Nordic Ltd., Estonia

This paper introduces a new approach to keep all extrusion die-related data together to standardize a collaboration format in the Aluminum Extrusion industry. It is an open format for integration of different files of the extrusion process into one compressed file, which is packaged from an initiator and made ready for subsequent access. Later, during the extrusion cycle, this file can be edited (by adding or deleting entries) and then can be used from different participants of the process.

DDD is the process file format for storing the entire life cycle of die from acceptance of the 2D profile drawing, through engineering design and manufacture, to FEA simulations, corrections and subsequent orders. It provides a die information backbone for die manufacturers as well as extruders.

Thousands of new dies are delivered every year, and manufacturers want to make sure that any follow-up orders of the same die will be immediately successful. To achieve this all the die-related data must be stored and maintained together.

Note: This is not a commercial software platform– it is a suggestion, which could be implemented in the industry. No commercial tools or software are needed to support this format.

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EP107

The Importance of 3D Design in the Aluminum Extrusion Industry               

Mehmet Akyar and Sinan Akyar, MIP Nordic Ltd., Estonia

In the traditional extrusion die, manufacturing dies are designed with 2D CAD systems. In this paper we will compare 2D and 3D design techniques and show the benefits of 3D design. In today's competitive extrusion die marketplace, time to market is of great importance, thus companies must create their dies quicker, cheaper and with a better quality , which means fewer "ECO's" (Engineering Change Order) and fewer "Prototypes". In addition, 2D designs are not ideal for representing a complex die, especially when communicating with the design team, customers, salespeople, buyers, and suppliers, as they are subject to misinterpretation and error, which, in turn, can become costly and time consuming. The possibilities for concurrent engineering take a real step forward with 3D models because the clear definition of a 3D design can be instinctively understood and acted on by other team members. Benefits of a 3D die model include:

• Return on investment
• Repeatability of subsequent dies
• Reducing die trials
• Accuracy of dies
• Documentation of corrections
• Capture of knowledge and experience
• Quality factors
• Connecting downstream applications such as CAM, FEA and PDM.
  
  

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EP116

Die-Making Retrospective

Roger A. P. Fielding, BENCHMARKS and The Virtual Company Inc., Canada

In 1974, only the United Computing Corporation could demonstrate a seamless connection between computer graphics and the Automatic Programmed Tool (APT) software. Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) systems were first applied to the design and manufacture of extrusion dies by Alcoa in Lafayette, and by Alcan Canada Products Limited (ACP), in its two die shops and five sales and product design offices located across Canada. In Alcan, the CAD systems drew in customers so that the systems were rapidly expanded. In 1983 a modern die shop was constructed in Markham, Toronto. Over the next ten years, Alcan and its affiliates' extrusion businesses located in 17 countries around the world, participated in the development of dies for products extruded from AA1xxx to AA7xxx alloys, and shapes ranging from multi-port micro-tubes to the wide multi-port structural shapes used in high-speed rail vehicles. In July 1994, Exco Technologies purchased the Markham facility from Alcan. This purchase was stated by EXCO to provide the Company with additional capacity in the extrusion tooling sector and proprietary technology. This paper discusses every aspect of die design and die making from selection and layout of machines and processes to the utilization of robotics, 3D printing and the need to eliminate polishing.

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EP118

Impact Study of Extruded Cross and Rectangular Aluminum Tubes for Improving Crashworthiness of Automobiles

Eboreime Ohioma, Muhammad Ali, and Frank Kraft, Ohio University, USA

This paper presents an experimental investigation on the crushing behavior and energy absorption capacities of two extruded geometric profiles; a cross and rectangle profile. The profiles were commercially produced in alloy AA6063 and of T6 and T7 tempers. Tensile tests were conducted to characterize the mechanical behavior of each heat treatment and profile for modeling efforts. The specimens were crushed under quasi-static axial compressive loads. Normal modes of collapse were observed for rectangular tubes, however crushing forces exceeded the test machine’s loading capacity for cross tubes. Geometric modifications in the form of horizontal grooves (or triggers) along the cross tube side walls were introduced to promote collapse. These grooves (trigger types 1 and 2) acted as collapse initiators which promote a controlled, stable, and repeatable folding pattern along the tube length during compression. They also serve as peak force reducers. The preliminary test results show improved symmetric folding modes, as well as tube stability during deformation for the type 2 trigger. Force-displacement curves will be presented to quantify the effect of grooves on the crushing force and stroke. Deformation modes will be compared with numerical simulations.

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EP125

How Controlled Nitriding and Ferritic Nitrocarburizing Improve Productivity, Quality, and the Bottom Line

Jack A. Kalucki, Nitrex Metal Inc., Canada

Nitriding and ferritic nitrocarburizing of ferrous alloys are thermochemical surface treatments used to increase hardness and toughness, protecting dies from wear and increasing the lifespan of expensive tooling. The key to the successful optimization of those processes for applications such as aluminum extrusion dies is precise atmosphere control, which allows for shaping the surface properties according to exacting specifications. The paper will explore aspects of process control fundamentals and subsequent metallurgical results directly related to aluminum extrusion dies. It will discuss the differences between controlled nitriding and nitrocarburizing in terms of hardness, wear resistance, and also cracking, flaking and other surface problems that affect profile quality. Finally, we present and discuss actual production data obtained in different aluminum extrusion plants, showing the influence of controlled nitriding or ferritic nitrocarburizing on die lifespan, wear, and the amount of corrections.

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EP129

Real-Time Prediction of Press QuenchProfile Distortion - Foundation and Challenges

David R. Jenista and Drew Griffioen, Granco Clark, Inc., USA

The extrusion quenching process has two sometimes conflicting requirements: cooling material sufficiently to meet required mechanical properties without distorting profile geometry outside of product tolerances. Critical temperatures and cooling rates necessary for individual alloys are well documented. Simulators based on thermodynamic and heat transfer theory have been developed to specify quench performance needed to meet the necessary temperatures and rates for given production conditions. The issue of profile geometry has not lent itself to simple solutions available to the average extrusion facility in real time. This paper reviews the foundational issues and identifies the challenges that must be overcome in order to provide readily accessible, real-time distortion analysis for the extrusion industry. After reviewing the foundation, Finite Element Analysis (FEA) is used to simulate quench-induced profile distortion during extrusion quenching evaluating the challenges. Building from the understanding of profile distortion gained via FEA, the potential exists for generating a rules-based system for real-time prediction of quench-induced profile distortion.

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EP135

A Study of the Influence of Parameters on Distortional Amount of the Extruded Bar in 6082 Aluminum Extrusion Process

Wonho Hwang, Joonkeun Lee, and Iksoo Jeon, LS Cable & System Ltd., South Korea

Recently, the automotive industry is under obligation to install the ABS/ESC. The MEB (MOBIS Electronic Brake) Block that is made by aluminum extrusion process is being required not only the higher qualities of the product but also the lower manufacture cost because there is increasing demand for installation of the ABS/ESC. Therefore, the first purpose of this investigation is to improve the qualities of the product with back-end defect and surface defect. The second purpose is to cut down the manufacturing cost. Dead Metal Zone and butt length of billet were estimated to improve surface and back-end defects, then the distortion of extruded bar was evaluated by studying the influence of parameters such as feeder depth/width and center alignment of the die opening in using the FEM simulation.

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EP137

Correlation of Surface Roughness to the Number of Billets Extruded to the Die Nitriding Cycle

Modar AlMekdad, Arif Hussain, and Mansoor Ali Khan, Gulf Extrusions Co. LLC, UAE

The main objective of this paper is to define a correlation between the surface roughness of the extruded aluminum to that of the number of billets extruded for a given die; in other terms this study tries to relate the surface roughness of the extruded aluminum to the deterioration of the nitrided layer over the number of billets run over a production cycle. In this study we monitor the surface roughness of the extruded aluminum right from the start of extrusion, wherein the die has just been nitrided by an optimum nitriding cycle to the surface roughness of the extruded aluminum over a finite number of billets run through the same die, and at the same time study the deterioration of nitrided layer over this extrusion cycle. Within this study we have also considered the influence of use of nitrogen cooling during the course of extrusion and its effect on the nitrided layer and also the surface roughness of the extruded aluminum. Due to the specific controlled requirements of surface roughness of extruded aluminum by most of the end users of extruded aluminum such as the automotive, pneumatic, industries, etc. Since controlling surface roughness over the extrusion cycle is challenging, it is very important to define a correlation between the surface roughness of the extruded aluminum and deterioration of the nitrided layer over an optimum nitriding cycle. Other factors such as the characteristics of the nitrided layer, the presence or absence of a compound layer and its thickness, ?/? ratio, and micro hardness of the nitrided layer, which consequently contribute to considerable scattering in die life during the process of extrusion of aluminum have been studied. Influence on the surface roughness of the extruded aluminum due to the deterioration of the nitrided layer and factors comprising the effect have also been reviewed.

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EP140

Effect of Double Aging and Room Temperature Aging on Properties and Stress Corrosion Cracking of AA7075

John Hasier, Satya Emani, John Valin, Philip Nash, and Joseph C. Benedyk, Thermal Processing Technology Center, Illinois Institute of Technology (IIT), USA

The process of double aging AA7075 has been demonstrated to lead to a substantial reduction of aging time over that required for T6 and with only about a 10% decrease in strength. This work investigates the effect of double aging on stress-corrosion cracking susceptibility of double-aged material compared with the T7 treatment conventionally used to improve the stress-corrosion cracking resistance of AA7075. The effect of room temperature aging prior to artificial aging has also been investigated since this is a common industrial practice after extrusion.

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EP146

The Use of Infrared Thermography in Aluminum Extrusion Plants

Jerome Fourmann, Rio Tinto-Aluminum Products Group, USA and Chris Jowett, Rio Tinto-Aluminum Products Group, Canada

Since the late 1990’s, infrared or thermal imaging cameras continue to be used in an ever expanding range of civil applications such as night vision, building inspection, heat loss and furnace efficiency. Thermography has become a sophisticated science involving the development of thermal cameras and IR detectors. Up to this time, their use in the aluminum extrusion industry has been relatively limited except is such area as predictive maintenance or occasionally to show the dramatic differences between good and bad die ovens or to illustrate non-uniformity in container assemblies. We hear ad nauseam that “there are 3 rules of extrusion: temperature, temperature, temperature”. One way to support this is through infrared thermography of the entire thermal extrusion process.
Rio Tinto Alcan estimates that today’s infrared thermography can find many purposes in aluminum extrusion plants. This paper illustrates how instructive and useful the technology has been in a range of applications including environmental control and process monitoring. Case studies have been conducted whereby extruders have measured temperatures and quantified the benefits that can be achieved by keeping temperatures under control.

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EP152

Effects of Manual Polishing on Die Bearings

Richard Dickson and Eskild Hoff, Hydro Aluminum Metals USA; Adam Cramlet and Dennis Ebnet, Alexandria Industries, USA; and Jon Veenstra, Wefa Cedar, Inc., USA

The DIMEX machine, a device for the precision measurement of die bearings, was introduced at ET'08, where it was used in a detailed study of the manufacturing capabilities of the die makers. That paper showed that using modern WEDM machines and CNC machining centers the repeatability and precision of the die bearing was quite impressive.
While the tools used in die making over the last 30 years have changed dramatically, the tools available to the die corrector have changed little in comparison. Most die bearings are cleaned and corrected using simple hand files or abrasive paper.
The impact of these manual or semi automatic polishing and cleaning procedures, has never been quantified. By the use of a DIMEX machine, this paper quantifies the impact of some of these various polishing/cleaning techniques on the die bearing geometry.

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EP154

Elevated Temperature Exposure Effects: A Comparison of 6xxx-Series and 7xxx-Series Alloys

Danielle Williamson and David Lukasak, Sapa Extrusions NATC, USA

Structural automotive extrusion applications are increasingly looking for higher strength solutions to further increase weight savings. In these automotive applications there can be exposure to elevated temperatures either through proximity to the engine compartment or during the assembly paint bake cycle. The aging kinetics of 6XXX and 7XXX alloys are very different with 7XXX alloys being faster. This paper explores the effects of elevated temperature exposure on strength of these two alloy systems.

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EP165

Microstructure Effects on Damage Evolution in Aluminum Weld Seams Studied through X-ray Computer Tomography

Andrew J. Den Bakker, Nedal Aluminium/Delft University of Technology, Faculty Mechanical, Maritime and Materials Engineering, The Netherlands; X. Wu, Delft University of Technology, Faculty of Aerospace Engineering; Lauren Katgerman, Delft University of Technology, Faculty Mechanical, Maritime and Materials Engineering, The Netherlands; and S. Van Der Zwaag, Delft University of Technology, Faculty of Aerospace Engineering

In this study, X-ray computer tomography is used to determine damage evolution in extrusion weld seams loaded close to failure. By utilizing two AlSiMg alloys with similar strength levels, but with distinctively different grain structures, the influence of the microstructure could be investigated. The grain structure obtained after extrusion is controlled by the dispersion content of the alloys. In the dispersoid-free alloy recrystallization occurs, while the dispersoid-rich alloy retains a heavily deformed microstructure. Samples were produced in closely controlled extrusion tests utilizing a semi-industrial scale extrusion facility. A dedicated die was designed for the production of a test profile. Mechanical characterization was performed through uniaxial tensile tests. Damage evolution was studied through X-ray tomography of pre strained samples loaded close to the failure stress. It was found that the presence of a weld seam has no effect on mechanical properties in the recrystallized alloy and no preferential void formation in the weld seam region was detected. In the non-recrystallizing alloy, the weld seam leads to a reduced ductility. There are no signs of internal void formation and damage initiation was found to be close to the surface.

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EP166

Advanced Aluminum Alloys Used in the Manufacture of Products in Extrusion Process

Bartlomiej Plonka, Institute of Non Ferrous Metals, Light Metals Division, Poland

The subject of the research was an alloy AlCuMgMn with addition of Zr and Sc manufactured from the extrusion process such as bars, profiles or tubes. The paper presents research results of the structure evolution and mechanical properties for different tempers of precipitation strengthening. The article also presents the results of the investigations of an AlCuMgMn(ZrSc) alloy produced in the form of powder. The powder of this alloy was subjected to consolidation in the process of direct hot extrusion. The aim of the study was to optimize the process of Al alloy powder hot extrusion using conical dies. Parameters of the powder consolidation process were determined in terms of the choice of the tool (die) geometry, and extrusion rate and temperature, allowing for an influence of these parameters on alloy density and mechanical properties after direct hot extrusion. Obtained results (Rm above 500MPa for AlCuMg alloy) shows significant possibilities of manufacturing from aluminum alloys powder products with ultrafine grain structure, the properties of which exceed alloys manufactured using standard methods.

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EP173

Pioneering Tool Steel Grades for Extrusion Tooling

Bryant K. Bronner, Werner Haehnel, and Emeline Meurisse, Kind & Co. Edelstahlwerk, KG, Germany

Kind & Co. develops and manufactures forged tool steels at its facility in Germany. More than 125 years of experience have provided us with the expertise and know how needed to further push the envelope in regards to material technology. In order to meet the ever rising demands in the extrusion industry, an onus has been placed on maximizing productivity. The characteristics of the tool steel used to make the extrusion tooling, goes a long way in helping extruders to achieve peak efficiency on their press. The ongoing dialogue between press makers, and our internal applications engineers, the extrusion experts that work on their respective presses on a daily basis, and the containers that come through our service center, provides a clear view in regards to the challenges that extruders face. This information is the catalyst for the research and development of new tool steels. Premium tool steels are exemplified by their higher resistance to heat, top notch toughness and exceptional levels of wear resistance. These characteristics are needed in order to prolong the service life of the tool, reduce down time, enhance the quality of the final product and to reduce cost.

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EP187

New Innovative Way of Die Tracking

Sutanay Parida, Taweelah Aluminium Extrusion Company (TALEX) LLC, UAE

Dies are the heart of any extrusion process. These dies move from one place to another inside the plant as per the requirement of the system. Due to the complex procedure, it is not possible to track the real-time data of a die on the floor. This ultimately resulted in an inaccurate delivery time calculation. Companies with a respected reputation take utmost care in bringing this gap as close as possible. Delivery date can be evaluated quite accurately by using Planning Engine software. But, to have more accuracy in evaluation, even the planning engine requires real-time data from floor.

Barcoding is the best solution to track the movement of any object. But, when a barcoding is applied on the die it cannot sustain the work environment such as caustic cleaning or wet blasting. As a result barcodes get destroyed and die lose their identities. Direct Part Marking technology could be a better solution. It has its own pros and cons. This paper shows our practical work on the floor and on the die to reach to a position for final implementation of the project.

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EP188

Control Procedure for Best Use of Aluminum Filled Dies

Sutanay Parida, Taweelah Aluminium Extrusion Company (TALEX) LLC; and Modar AlMekdad, Gulf Extrusions Co. LLC, UAE

In an aluminum extrusion process used-dies have to be cleaned in a caustic soda solution followed by inspection, correction or polishing. These dies are kept in store as ready-dies for arising production. Many extruders keep the Aluminum-filled-Dies close to the press and use it in the next production opportunities. This practice is found to be successful in frequently repetitive nature of orders. However, in case of product-mix with frequent repeat orders and large project orders, this system becomes uncontrolled especially due to the die logistic problem. However, with the introduction of computerized-control-system, Aluminum filled dies can also be used in a very efficient way.

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EP193

Blisters and Their Many Causes

Tony Da Silva, APEL Extrusions, Canada

Blisters are one of the most common defects in the aluminum extrusion process, but it is challenging to trace their root cause since there are a multitude of potential causes. This abundance of potential causes hinders the troubleshooting process, making it more complex and tedious. This paper describes the most common causes of blisters and helps the extruder to troubleshoot this problem by applying Kepner-Tregoe's "IS / IS NOT" Problem Analysis system and by identifying the different morphology of blisters and their related, yet different causes. The results of several experimental trials are reported which point towards best practices for blister reduction. One such series of tests supports the well-known view that two piece billets produce significant blisters, but it also shows that the use of log saws instead of hot shears is not a solution. It also considers the influence of the shape itself on the frequency or likelihood of an occurrence of blisters. Finally, it discusses the current difficulty that press managers have in their efforts to eliminate the causes of blisters and the production of blister free profiles.

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EP198

Impact of Severe "Shoe Shine" Polishing on Bearing Geometry

Richard Dickson and Eskild Hoff, Hydro Aluminum Metals USA; Adam Cramlet and Dennis Ebnet, Alexandria Industries, USA; Jon Veenstra, WEFA Cedar, Inc., USA; and Pawel Kazanowski, SAPA Precision Tubing Technology Center, USA

The aim of the present work is to develop a unified model to predict the grain evolution of 6XXX aluminum alloys, during deformation and subsequent dynamic and static recrystallization, and validate it by use of Qform, a Lagrangian FE Code. Experimental data were obtained from two previous backward extrusion campaigns (AA6060-O and AA6082-O), that were performed at different conditions of temperature and strain rate. All the specimens were subjected to microstructural analysis in terms of grain size evaluation, before extrusion (initial grain size), after extrusion (evaluation of dynamic recrystallization) and after heat treatment (evaluation of a fully static recrystallization). The model is implemented through user defined routines; batches of simulations were carried out for each material in order to fit the best parameters that determine the final grain size at 100% of recrystallization material through comparison between numerical results and experimental grain size. Through the experimental data it was possible to validate the theoretical model for the grain size and shape evolution during dynamic recrystallization, obtained from previous numerical simulations.

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EP204

The Extrusion of Two-Piece Billets

Tony Da Silva, Apel Extrusions, Canada

The advent of hot log shears and hot log saws helped the soft aluminum extrusion industry to transition from pre-cut billets to logs cut to length. This has helped the aluminum extrusion industry to increase its overall efficiency. On the other hand, there is an adverse and undesired consequence in the use of this technology. This undesired consequence is the use of a two-piece billet to improve recovery. The log shear and log saws generate a two-piece billet when the remaining log can no longer allow a full billet cut. In many cases, the use of a two-piece billet does not come without compromises. A two-piece billet is associated with the presence of a second transverse weld and a high occurrence of blisters in many shapes. The use of two-piece billets can reach, under certain circumstances, as high as 40 percent of the total billets run and therefore, it is essential for the extruder to better understand the extrusion process. This study is devoted to better understand the occurrence of blisters, the upset, and metal flow in a two-piece billet.

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