Cast Shop Technology: On-Demand Oral Presentations
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Stephen Instone, Speira Gmbh; Mertol Gokelma, Izmir Institute of Technology; Samuel Wagstaff, Oculatus Consulting; Dmitry Eskin, Brunel University
Monday 8:00 AM
March 14, 2022
Room: Light Metals
Location: On-Demand Room
Digital Twin for Design and Optimization of DC Casting Lines: Knut Omdal Tveito1; Arild Håkonsen2; 1Hydro Aluminium; 2Hycast AS
The design of DC casting lines requires a careful consideration of metal temperatures, flow rates and automated control, with particular focus on the startup phase. While many parameters such as temperature losses and flow rates can be estimated, the calculation of filling rates and control systems performance requires theory of transient two-phase flows for accurate predictions. Detailed two-phase CFD simulations have been used to develop a reduced-order model capable of running in real-time. With a modular approach the digital twin can then be used to analyze different launder layouts/designs, degassers, filters and their effect of on key parameters such as startup temperature, filling rates and level control. The use of the digital twin in the development and implementation of a new Hycast LPC casting line is demonstrated and predictions compared to experimental data. Further use cases such as control system optimization, intelligent process control and online deviation detection is discussed.
Analytical, Numerical and Experimental Investigations of Transient Heat Conduction in Launder during Casting Process: Akash Pakanati1; Knut Tveito1; 1Norsk Hydro
Liquid metal temperature in the casting table needs to be controlled to avoid defects and assure process stability during DC-casting. Simple analytical models can provide us with an insight into the temperature loss as liquid metal moves from the furnace through the casting line and could be used to regulate the temperature of the liquid metal entering the casting table. Part of the heat losses comes from conjugate heat transfer between refractory launders and liquid metal. Hence, prediction of the transient temperature field in the refractory during casting becomes a critical element in being able to predict the temperature loss in the liquid. In this study, we use a simple analytical model to estimate the temperature field in the refractory due to its contact with the liquid metal. The analytical results are compared with both experimental data from casting trials and simulation models (1D and 2D).
The Local Squeeze Technology for Challenging Aluminium HPDC Automotive Components: Elisa Fracchia1; Federico Simone Gobber2; Claudio Mus3; Raul Pirovano4; Mario Rosso1; 1INSTM c/o Politecnico di Torino; 2Politecnico di Torino; 3Endurance Overseas; 4XC Engineering Srl
A key issue in producing high-quality aluminium automotive components by the High-Pressure Die Casting process (HPDC) is minimizing the defects. For the HPDC technology, the wall thickness of components needs to be monitored because it dramatically affects the grain size and pore's appearance. In this work, local squeeze technology is used in aluminium high-pressure die casting. The aim is to optimize quality in thick sections of complex geometries, where designers cannot modify component's features and the casting process cannot solve shrinkage porosities with the state of the art process control like intensification pressure or cooling management. The present paper relates to a study of the squeeze pin effect on HPDC aluminium parts, where material homogeneity for leak prevention is a must. Both product and process development for reliable industrialization of the local squeeze technology will be covered, from casting virtual simulation to the metallurgical analysis of the affected area.
Quantitative Assessment of Operational Parameters on Die Temperature during an Industrial Low-pressure Die Casting Process: Jun Ou1; Chunying Wei1; Steve Cockcroft1; Daan Maijer1; Lin Zhu2; Lateng A2; 1UBC; 2Dicastal Co., LTD
Driven by the rapid technological innovation in the automotive industry, automotive parts suppliers are engaged in developing next-generation process control methods that incorporate historical process knowledge and data from online process monitoring. This work examines how the casting process control variables and process variability affect die temperature using quantitative data acquired from a series of experiments performed on a commercial low-pressure die casting (LPDC) process for automotive wheel production. The control parameters considered include the pressure fill-curve, cooling duration, water flow rates and environmental temperatures. It was found that the cooling duration exerts the most significant impact on the die temperature. In contrast, the flow rate of cooling water only slightly influences the die temperature, particularly when the flow rate is below 300 l/h. Additionally, there was no noticeable influences caused by adjusting the pressure fill-curve and environmental temperatures in the ranges tested.
Casthouse Furnace Tending: A New Approach Thanks to Custom Robotics: Jean Francois Desmeules1; Robert Dumont1; 1Dynamic Concept
Furnace tending is one of the activities within the casthouse which most depends on operators. Due to the large dimensions of melting and holding furnaces, the equipment used for tending, also of large dimensions, is either mobile and operated by humans, or mounted on rails. Robotics integration is limited, because standard robots are designed for high speeds with small payloads, while slow speeds at large payloads are required. To overcome these limitations, a custom robot has been designed, integrating innovative features such as portability (onboard energy supply) and high payload capacity. This paper explains how the various design constraints were overcome by designing a custom geometry for the robot.
Short- and Long-term Aluminum Filtration Trials with Carbon-bonded Alumina Filters: Claudia Voigt1; Jana Hubálková1; Are Bergin2; Robert Fritzsch2; Shahid Akhtar3; Ragnhild Aune2; Christos Aneziris1; 1Institute Of Ceramics, Refractories And; 2Department of Materials Science and Engineering, Norwegian University of Science and Technology; 3Hydro Aluminium AS, Karmøy Primary Production
In the present study carbon-bonded alumina filters, normally used for the filtration of steel melts, have been investigated as a potential filter material for filtration of aluminum. Short- and long-term pilot scale filtration trials were conducted, and the filter behavior during filtration of aluminum alloy was determined by the use of PoDFA (Porous Disk Filtration Apparatus) for the short-term trials (with the casting alloy AlSi7Mg) and LiMCA (Liquid Metal Cleanliness Analyzer) for the long-term trials with wrought alloy 6xxx aluminum. All applied filters were also investigated post-mortem by SEM (Scanning Electron Microscopy) analysis. Furthermore, sessile drop experiments with capillary purification were performed to evaluate the wetting behavior as well as any reactions occurring between the filter material and the aluminum alloy being filtered.
Adaptive Tempering in High Pressure Die Casting through Prediction Functions: Torben Disselhoff1; Sebastian Tewes1; Sebastian Biehl2; 1University Duisburg-Essen; 2thermobiehl Apparatebau GmbH
Digitisation and cross-linking in high pressure die casting technology (HPDC) have developed greatly over the past few years. In modern HPDC cells, almost all parameters are recorded and evaluated with the aim of achieving optimum casting production in terms of quality, cycle time and energy efficiency. However, the focus of this process data analysis and recording is particularly on the HPDC system itself and less on the periphery. This leads to possible interactions remaining undetected and avoidable casting defects continuing to occur. Therefore, the so-called tempering process, which is gaining more and more importance due to the shift towards minimum quantity spraying, is investigated in this research work. In particular, the process parameters of all tempering circuits, which change over time, are analysed with machine learning, and linked with quality-relevant machine key performance data of HPDC machine. The resulting prediction functions generate process control options to holistically optimise casting production.
Aluminum Melt Cleanliness Analysis Based on Direct Comparison of Computationally Segmented PoDFA Samples and LiMCA Results: Robert Fritzsch1; Hannes Zedel1; Trygve Schanche1; Are Bergin2; Shahid Akthar3; Lars Arnberg1; Ragnhild E. Aune1; 1Dept. of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU); 2Hydro Aluminium AS, Commercial Technology, Sunndalsøra, NORWAY; 3Hydro Aluminium AS, Karmøy Primary Production, 4265 Håvik, NORWAY
Several methods exist in industry for the measurement of the inclusion content in aluminium, a measure directly related to the cleanliness of the molten metal. In the present pilot scale study, Porous Disc Filtration Apparatus (PoDFA) analysis and the Liquid Metal Cleanliness Analyser (LiMCA) were used to determine metal cleanliness. Hot-PoDFA samples and continuous LiMCA measurements were taken out both before and after the ceramic foam filter (CFF). Metal cleanliness data obtained from the PoDFA samples were compared with in-situ LiMCA measurements by correlating metal cleanliness data calculated by counts per area in the case of PoDFA with the counts per volume in the case of LiMCA. The comparability of both methods is discussed in the context of filtration theory and the distinctiveness of both systems.
Numerical and Experimental Investigation of Heat Transfer in the Solidification-deformation Zone during Twin-roll Casting of Aluminum Strips: Olexandr Grydin1; Dag Mortensen2; Moritz Neuser1; Dag Lindholm2; Hallvard Fjær2; Mirko Schaper1; 1Materials Science, Paderborn University; 2Institute for Energy Technology
During the twin-roll casting of strips, the heat exchange between the internally water-cooled shells and the metal has a great influence on the strip forming conditions, such as the sump depth, plastic flow, surface and centerline segregations and run-out temperature of a strip, which determine the strip quality. In this study, laboratory-scale experiments were carried out on the twin-roll casting of strips made of the aluminum alloy EN AW-6082 with simultaneous temperature measurements at the shell surface and within the solidification-deformation zone. While the shell temperature was monitored with an infrared camera, a 0.5 mm diameter shell thermocouple was passed through the solidification-deformation zone after the thermal steady state was reached. Subsequently, a finite element numerical model of the laboratory-scale twin-roll casting trial was developed. An angle dependent heat transfer coefficient was fitted to the experimental results, thereby indicating a spatial resolution of the heat transfer at the aluminum-shell interface.
Microstructural Modification of a High-pressure Die-cast A380 Alloy through Friction Stir Processing and Its Effect on Mechanical Properties: Avik Samanta1; Hrishikesh Das1; David Garcia1; Robert Seffens1; Timothy Roosendaal1; Anthony Guzman1; Glenn Grant1; Saumyadeep Jana1; 1Pacific Northwest National Laboratory
Aluminum alloy A380 is one of the major high-pressure die-cast (HPDC) alloys fabricated in the die casting sector. However, microstructural features such as shrinkage and gas porosity, entrapped oxide inclusions, change in the morphology of eutectic Si particles as a function of casting location, and the presence of multiple second phase particulates, especially Fe-bearing phases in HPDC A380 alloy results in limited ductility, thus, affecting its structural application. However, through proper modification of the as-cast microstructure, it is possible to improve the mechanical performance of alloy A380. In this study, we report the effect of friction stir processing (FSP), a well-known severe plastic deformation (SPD) and thermomechanical processing tool for selective microstructural modification, on A380. FSP effectively refines the as-cast microstructure and breaks down the coarse Si particles, creating a homogenized distribution of equiaxed Si particles in the aluminum matrix. Additionally, FSP eliminates porosity that acts as crack initiation sites, leading to improved mechanical strength and ductility.
Control Pin Refractory Reaction in High Magnesium Aluminium-melts: Reiza Mukhlis1; John Grandfield2; M. Akbar Rhamdhani1; 1Swinburne University of Technology; 2Grandfield Technology Pty Ltd
Through 2019, pin hole defects were observed in can end 5182 Al sheets produced at Hulamin. Initial SEM examination revealed the presence of Al-Mg-O spinels inclusions with silica traces. The lack of calcium and phosphorous in the inclusions suggested that fused-silica pins and downspouts reacted with magnesium in the melt. The authors have carried out a systematic study to investigate the mechanism further which included pin-immersions tests, thermodynamic analysis, and SEM examinations. The thermodynamic analysis, confirmed in the immersion test, showed that at low magnesium content MgO forms as the reaction product but at higher magnesium levels AlMgO4 forms. It seems likely that the reaction products take up more volume which would cause further spalling of the fused-silica and BN-coating. The importance of examining and maintaining the integrity of the BN-coating was highlighted to prevent melt-to-pins reaction. It is speculated that lower porosity pins would be more resistant to attack.
The Great Debate - High vs Low Water Direct Chill Casting Pits - Which is Safer: Alex Lowery1; 1Wise Chem LLC
Some in our industry believe high water vertical direct chill casting pits are less likely to have a molten metal explosion than a low water vertical direct chill casting pit. This lack of knowledge is very bad and leads to an increase danger to workers in our industry. My paper addresses the issue of molten metal explosions with special attention to the differences between high and low water vertical direct chill casting pits. Specifically, in my project, I will be looking at the potential damage of molten metal explosion caused to workers, equipment, and facilities. I argue that high water direct chill vertical casting pits are actually more dangerous than low water direct chill vertical casting pits. In conclusion, this project, by closely examining molten metal explosions, sheds new light on the rarely acknowledge issue of hazards associated with high water pits.
Predicted Back-meniscus Stability for the Horizontal Single Belt Casting (HSBC) with Single Impingement Feeding System: Daniel Ricardo Gonzalez Morales1; Mihaiela Isac1; Roderick Guthrie1; 1McGill Metals Processing Center
Horizontal Single Belt Casting is one of the emerging Near-Net-Shape-Casting (NNSC) Processes for producing thin strips directly from liquid metal. It has been shown to have several advantages compared to the traditional Continuous Casting (CC), and Direct Chill (DC) casting methods. Nevertheless, some process conditions need to be thoroughly controlled to obtain high-quality metal strip material. Two of these are the “back meniscus” and metal “backflow” behavior. In the present research, the effects of the gap clearance between the back refractory and the belt, the belt speed, and the role of contact angle, are studied for the belt casting of AA2024 Aluminum alloy, using the commercial Computational Fluid Dynamics (CFD) software, ANSYS-Fluent 19.1. Combinations of variables were evaluated, to obtain the optimal set of processing parameters needed to promote “back meniscus” stability for the HSBC process for a vertical, single – impingement, metal feeding system.