Cast Shop Technology: Melting and Casting
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Johannes Morscheiser, Novelis Koblenz GmbH

Tuesday 8:30 AM
February 25, 2020
Room: 1B
Location: San Diego Convention Ctr

Session Chair: Samuel Wagstaff, Novelis


8:30 AM Introductory Comments

8:35 AM  
Mold Shape Control for Direct Chill Ingot Casting: Craig Cordill1; 1Wagstaff
    Aluminum direct chill ingot casting with dynamic rolling face mold walls provides many benefits to casters and rolling mills. Among these are higher casting speeds, less scalp, and safe higher ingot stacking. A newly developed system uses 3 active and 2 passive points on each rolling face mold wall to control the ingot’s profile. Positioning the points along the mold wall prior to a cast allows profile optimization for nearly any mold size. The active points are controlled to move the rolling face mold walls up to a predetermined position at any particular cast length. The length of movement is developed to match the alloy, casting speed and other various factors. The operational principle, as well as laboratory and field results are presented.

9:00 AM  
Continuous Monitoring of Butt Curl Development During DC Casting – Development and Application: Gerd-Ulrich Gruen1; Werner Droste1; Daniel Krings1; Mark Badowski1; Markus Hagen1; 1Hydro Aluminium Rolled Products GmbH
     Cast start situations for rolling ingot DC casting can represent severe risks for cast shop workers due to unforeseen development of butt curl of individual ingots. Hydro’s R&D center Bonn has the ambition to provide procedures and related tools helping to preventing these risks. In order to react on the critical development of butt curl of individual ingots in a casting unit a monitoring of relative motion of the bottom side of the solidifying ingot to the starter block is required. This means a continuous distance measurement under extremely harsh conditions. Possible solutions have to be watertight, heat resistant, need wireless data transmission capabilities and implementation and preparation of the system have to be user-friendly. Current status of the development includes real-time visualization and data storage in the process control system.This paper describes the technological approach, the testing under plant conditions and application examples of the system.

9:25 AM  
Constellium's Mold Technology for Al Alloy Slab DC Casting: Philippe Jarry1; Olivier Ribaud1; Laurent Jouët-Pastré2; Emmanuel Waz1; Pascal Delaire1; Pierre-Yves Menet1; Marc Bertherat1; Pierre Celle1; 1Constellium C-TEC; 2Constellium Neuf-Brisach
    DCC mold developments aim at meeting criteria either internal or external to the castshop. To the first category belong operational robustness, mold simplicity, mold versatility in terms of alloys and water quality, that is the possibility to obtain very high recovery rates whatever the alloy hot cracking or curling tendency, in any casthouse regardless of its particular water supply. To the second category belongs the minimisation, potentially the suppression of butt sawing before rolling. Constellium has striven to suppress butt cracking during start-up and surface cracks in steady state. Also, the butt curl pattern can have significant impact on cracking affecting unsawn butts during rolling. This has led us to reconsider the choice of jets angles and start-up strategies of the commercially available technologies, and eventually to develop our own mold technology, now patented and widely deployed within Constellium.

9:50 AM  
Fluid Flow Analyses and Meniscus Behavior during the Horizontal Single Belt Casting (HSBC) of Aluminum Alloy AA6111 Strips: Roderick Guthrie1; Mihaiela Isac1; 1McGill Metals Processing Centre
    The Horizontal Single Belt Casting (HSBC) process involves feeding molten metal, iso-kinetically, onto an intensively water-cooled, moving belt, which acts as the mold. Managing the bottom surface quality of the as-cast strip is a key factor in the success of the HSBC approach. The quality of strips is directly dependent on fluid flow behavior within the delivery system, the shape of the metal delivery system, the texture of the cooling substrate, meniscus behavior at the oscillating triple point of contact between melt/cooling substrate/air at the refractory back-wall, as well as the interfacial heat transfer between the melt and cooling substrate. The present research focusses on fluid flow analyses and meniscus behavior during the HSBC casting of various aluminum alloys. High Performance Computational Fluid Dynamic Modelling was validated by full-scale casting experiments.

10:15 AM Break

10:30 AM  
Effect of Water Flow Distribution on the Performance of Aluminum Small-form Ingot Continuous Castings: Lei Pan1; Eric Laplante1; Francis Breton1; 1Rio Tinto
     Small-form ingot casting lines are widely used to produce pure and foundry aluminum alloys due to their productivity and the convenience of small form ingots for re-melting and handling operations. The throughput of small-form ingot lines is typically determined by the length of the ingot chain. Longer chains allow higher productivity by maintaining the primary cooling time. To reduce the primary cooling time, fundamental understanding of the thermal dynamic is needed. This paper presents the effect of water flow distribution in the cooling basins on the ingots solidification and ingots constraint stress. The water flow parameters at three sections in the cooling basin were tested. The complete ingots cooling profiles, mould temperature profiles and the demoulding rate in correlation with the water flow distribution were evaluated. Key process parameters and issues were identified during the study, and the best practice was explored to secure the ingot quality and casting performance.

10:55 AM  
Small Scale Oxidation Experiments on AlMg Alloys in Various Gas Fired Furnace Atmospheres: Anders Johansson1; Egil Solberg2; Magnus Skramstad3; Thomas Kvande4; Johannes Lodin5; Nicholas Smith-Hanssen6; Martin Syvertsen6; Anne Kvithyld6; 1Granges; 2Alcoa; 3NTNU; 4Hydro; 5Linde; 6SINTEF
     Oxidation is of great interest in the cast house, as oxidation equates to metal loss. Therefore, a method to study the oxidation in a casthouse was developed and tested on AlMg alloys and AlMg alloys with beryllium additions under a variety of atmospheres created by an airfuel or oxyfuel burners. Samples of around 65 grams with between 0 and 5 % Mg were placed in small steel or ceramic crucibles and further placed in a gas-fired box furnace for times between 10 min and 6 hours. The sample mass was recorded after cooling to quantify the oxidation extent with respect to both alloy and atmosphere. Microscopic analysis of selected samples showed that a MgAl2O4 layer had formed on the surface and that at higher Mg contents internal oxidation occurred resulting in the formation of MgO or MgAl2O4 clusters in the melt. The results show promise for a method to give an increased understanding of the oxidation in the casthouse.

11:20 AM  
Study of the Oxidation of an Al-5Mg Alloy in Various Industrial Melting Furnace Atmospheres: Johannes Lodin1; Martin Syvertsen2; Anne Kvithyld2; Anders Johansson3; Egil Solberg4; Thomas Kvande5; 1Linde; 2SINTEF; 3Gränges AB; 4Alcoa; 5Hydro Aluminium
    In an industrial furnace, fired with a hydrocarbon-based fuel, the furnace atmosphere will essentially consist of a mixture of the four species: CO2, H2O, O2 and N2, all of which thermodynamically will react with aluminium. Earlier publications have addressed the question of the thermodynamic versus the kinetic driving forces for oxidation and dross formation of liquid aluminium alloys. Most of these studies have been performed in a laboratory environment with samples in the order of magnitude of 1g or less. This paper describes a series of studies where 10 kg samples were molten in a pilot scale furnace, using burners fired with LPG and LNG and with controlled flows of gas components to produce various mixtures of the four gaseous species. The weight gain of the Al-5Mg samples were monitored to determine the degree of oxidation and dross formation.