Cast Shop Technology: Melt Treatment
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Johannes Morscheiser, Novelis Koblenz GmbH
Tuesday 2:00 PM
February 25, 2020
Room: 1B
Location: San Diego Convention Ctr
Session Chair: Mark Badowski, Hydro
2:00 PM Introductory Comments
2:05 PM
Batscan, Constellium In-melt Ultrasonic Inclusion Detector: Industrial Performance: Jean-Louis Achard1; Nicolas Ramel2; Guido Beretta1; Pierre-Yves Menet1; Jocelyn Prigent1; Pierre Le Brun1; 1Constellium C-TEC; 2Constellium Neuf-Brisach
The Constellium in-melt ultrasonic inclusion detector has been evaluated in the real conditions of an industrial casting line. Various potential failure modes have been systematically investigated in order to develop reliable technical solutions in view of the final industrial version. The detector must meet strict requirements for industrial use. In particular, it must be fully automated and autonomous, with automatic safety procedures to preserve the device in case of metal level anomaly or other alert of the casting line supervision system. Data post-treatment has been developed on the acquisition system including a calibration procedure. In order to guarantee signal stability during the measurement, both the cooling system design and the assembly mode have been optimized. Typical events known to affect melt inclusion content will be illustrated, based on more than 1 year of industrial operation. This includes measurements at the casting furnace exit, degasser exit, and filter exit.
2:30 PM
Benchmark and Practical Application of State of the Art Hydrogen Monitoring: Arnis Pelss1; Johannes Morscheiser1; Sebastian Radwitz1; Jens Kremer1; Andreas Gilles1; 1Aleris Rolled Products Germany GmbH
The knowledge of the hydrogen content in liquid aluminium alloys is a prerequisite for an effective control of the degassing efficiency and therefore the quality of the final product. This paper describes the procedure and the results of an extensive benchmark study on the most common devices for online measurement of hydrogen in casting launders, Alscan and Hycal. Both devices were tested in lab scale experiments at various known hydrogen levels, which were established by purging with different reference gas mixtures until equilibrium. In addition, extensive tests were carried out in a pilot casting facility as well as in a production cast shop on different alloys and in various positions between holding furnace and casting station. The results of these tests as well as the consequences for the following implementation and automation of the selected device will be part of this paper.
2:55 PM
Molten Aluminum Quality Evaluations for Thin Foil Products: Ali Ulus1; Çisem Doğan1; Ali Ulaş Malcıoğlu1; Anıl Özkaya1; Eren Toraman1; 1Asaş Aluminium
In aluminum casting, metal refining affects the quality of final material as well as the metal performance in the subsequent process. In particular, the importance of refining increases in foil product group as the thicknesses become thinner. Pinhole / hole performance is a consideration in the packaging foil product group. In this study, two different filters were used to refine 8XXX series aluminum alloy during twin roll casting process. Inclusion analysis was performed from 8XXX series aluminum alloy strips cast by industrial scale with optical emission spectrometer to observe effects of refining. The main examination of the study is the pinhole / hole quantity and density analysis to determine the quality of final packaging film. All tests were evaluated by comparing the results of the 8XXX series aluminum sample cast with a standard filter.
3:20 PM
Industrial Verification of One- and Two-chamber Siphon Degassing: Arild Hakonsen1; Terje Haugen1; 1Hycast AS
Removal of dissolved Hydrogen from liquid Aluminium prior to casting is industrial standard today. The challenge the casthouses face is to remove as much Hydrogen as possible with as low cast as possible. Cost drivers for degassing is energy and Argon consumption in addition to drain metal, maintenance and consumable parts. Hycast has for almost two decades supplied a drain free two-rotor siphon degassers for metal flow rates up to 75mt/h (I-60 SIR), and has recently launched a one-rotor version for metal flow rates up to 25mt/h (I-25 SIR). This paper is a summary of the industrial results gained over these years.The effect of the relative Argon flow rate to the metal flow rate, the alloy composition and the rotor speed on the removal efficiency is investigated. One conclusion found from the measurements is that the Hydrogen concentration within one degassing chamber is close to constant.
3:45 PM Break
4:00 PM
Evaluation of CFF and BPF in Pilot Scale Filtration Tests: Martin Syvertsen1; Inge Johansen2; Anne Kvithyld1; Britt Elin Gihleengen3; Shahid Akhtar2; Are Bergin2; Anders Johansson4; 1SINTEF Industry; 2Hydro Aluminium; 3Hycast; 4Gränges
Eight filtration tests have been done at Hydro Aluminium's reference centre at Sunndal. Two different grades of CFF (Ceramic Foam Filter) and two different grit of BPF (Bonded Particle Filter) from Pyrotek were tested. The alloy were the same each day. The inclusion content in the melt was measured with LiMCA II and PoDFA before and after the filter. These measurements are used to calculate the removal efficiency and capacity of the various filter types.
4:25 PM
Dynaprime Filtration Technology Experience at Alcoa Baie-Comeau: Jean Francois Desmeules1; Francis Caron2; 1Dynamic Concept; 2Alcoa
The patented Dynaprime vibration assisted priming filter was developed in partnership by Alcoa and Dynamic Concept to provide high efficiency melt filtration at competitive capital and operation costs. Following laboratory, pilot and plant testing, a first industrial unit was installed at the Baie-Comeau plant. After over a year of continuous operation, the technology is now mature and actual metallurgical and operational data is available. Several different alloys with various filtration requirements are produced. The purpose of this paper is to present a summary of the plant experience with the equipment, including metallurgical results as well as operation and maintenance cost comparison with other filtration technologies.
4:50 PM
Improving Ultrasonic Melt Treatment Efficiency Through Flow Management: Acoustic Pressure Measurements and Numerical Simulations: Tungky Subroto1; Dmitry Eskin1; Christopher Beckwith2; Iakovos Tzanakis3; Georgi Djambazov2; Koulis Pericleous2; 1Brunel University; 2University of Greenwich; 3Oxford Brookes University
The current challenge for upscaling the ultrasonic melt treatment technology to industrial scale is to improve treatment efficiency using a single-sonotrode setup. To achieve this we suggest two innovative approaches: increasing melt residence time and exploiting acoustic resonance phenomenon. This can be achieved through flow management in a launder by partitions where the resonance length within the partitions is equal or at integer steps to the wavelength of the incident sound wave. This study focuses on acoustic pressure measurements at different partition configurations and flow conditions combined with numerical modelling of the process. The measurements are done both in liquid aluminum and in water as its transparent analogue. The acoustic pressure measurements are then used to assess melt treatment improvement through cavitation activity and pressure distribution in the launder as well as to verify and further develop the numerical model.