Sponsored by: MDMD Solidification and SCAMP Committees
Program Organizers: E.F. Matthys, Mechanical Engineering Department, University of California, Santa Barbara, CA 93106; W.G. Truckner, Technical Director--Product Development, Alcoa Technical Center, Alcoa Center, PA 15069
Monday, AM Room: B3
February 5, 1996 Location: Anaheim Convention Center
Session Chairperson: A. Cramb, Carnegie Mellon University, Dept of Matls Sci, Pittsburgh, PA 15213; E.F. Matthys, University of California, Dept of Mech Engrg, Santa Barbara, CA 93106
8:30 am Invited
CONTINUOUS CASTING OF ALUMINUM - AN ALCOA PERSPECTIVE: STATUS AND POTENTIAL FOR PROGRESS: P.N. Anyalebechi, R. Bachowski, S.F. Baumann, O. Richmond, A.J. Sartschev, W.G. Truckner, Alcoa Technical Center, Alcoa Center, PA 15069
Over the past 25 years, continuous casting is the Al industry has grown steadily, although this growth has been mostly confined to "common alloy/products" such as foil, conductor rod, building products, selected food packaging alloys, etc. This growth has been driven essentially from process economics (compared to ingot based metal). Development of products requiring higher levels of performance such as beverage can stock, automotive sheet, surface sensitive products, etc. has been difficult. This difficulty can be traced to the lack of understanding of the complex processes occurring during continuous casting. Experience over the years has provided some valuable information; however, much more understanding is required to answer metallurgical and surface concerns. This paper will address, from Alcoa's perspective, these problems and will be discussed and presented in terms of research opportunities that need to be solved before continuous cast products begin to compete from both a performance and economic standpoint in the higher performance markets now served by ingot based processes.
AN UPDATE ON THIN-GAUGE/HIGH-SPEED ROLL CASTING OF FIN AND FOIL PRODUCTS: Bill Carey, Norandal USA, Inc., Brentwood, TN. Bruno Taraglio, Fata Hunter, Inc., Torino, Italy; Chris Romanowski, Fata Hunter, Inc., Riverside, CA 92507
The cast house at Norandal's Huntingdon facility has been expanded to accommodate a fourth FATA Hunter Casting line. The new line features a 2184 mm (86") wide SpeedCaster(TM) scheduled for start-up in late 1995. This installation will be the world's first production thin-gauge/high-speed twin roll caster for aluminum. The specifications for each of the major pieces of equipment in this installation are reviewed in the written paper and the presentation will include a video showing the operation of the casting line. An overview of the start-up program and initial performance of the caster in terms of productivity, product quality and up-time will also be presented. The written paper outlines and compares the investment cost for a new foil plant based on this thin-gauge/high-speed casting technology with the cost of a conventional SuperCasterreg. plant.
FASTCAST - THE FIRST OF A NEW GENERATION OF ROLL CASTERS: P.M. Thomas, Davy International, Poole, BH12 5AG, United Kingdom
Over the past few years, high speed thin strip casting has gained credibility as an emerging technology. It has been established that the process differs from conventional roll casting in a number of key areas and offers a number of potential benefits including reduced capital and operating costs, increased productivity and freedom from the alloy limitations associated with conventional roll casting. As a result of an extensive development program on both laboratory and pilot scale casters, the importance of separating force as a process variable has been established. Based on the knowledge gained during the experimental program, it has been possible to engineer a caster for commercial operation. This machine differs fundamentally from conventional twin roll casters in a number of ways. To accommodate the high separating forces necessary to product good quality material at thin gauges the casting rolls are supported by back up rolls in a 4 - High construction. This construction will provide material with superior gauge and profile tolerances and with a microstructure compatible with downstream processing requirements. The first FASTCAST machine is currently being built for Granges Eurofoil for the production of 1800mm wide foil stock and commissioning is scheduled for November, 1995.
10:00 am BREAK
PROCESS AUTOMATION FOR HIGH SPEED - THIN-GAUGE - TWIN ROLL CASTING TECHNOLOGY: K.P. Maiwald, B. Mariethoz, Lauener Engineering LTD, CH-3645 Gwatt/Thun, Switzerland
The successful joint venture development between Lauener-Engineering and Hydro-Aluminum in respect to thin gauge-high speed casting demanded a highly sophisticated process-control system. The targets of 100% (and above) productivity increases and gauges of 2mm and below within tolerances of +/- 1% and below where reached on time. The paper will explore details of the process control system applied from furnace to caster and coiler.
DEVELOPMENT AND COMMERCIALIZATION OF A 3000 SERIES BODY STOCK ALLOY USING THE LAUENER BLOCK CASTER: B. Newton, Golden Aluminum, Golden, CO 80401
The paper describes the start up experiences at the San Antonio Mill - Texas and follows alloy and product development which lead to the commercialization of Golden's Body Stock. The paper examines the transition from the initial 5349 alloy to the current 3000 series alloy.
ELECTRO-SLAG REFINING AS A LIQUID METAL SOURCE FOR MELT-SPINNING, STRIP CASTING AND SLAB CASTING: M.G. Benz, W.T. Carter, R.J. Zabala, B.A. Knudsen, P.L. Dupree, GE Corporate Research and Development, Schenectady, NY 12301; R.M. Forbes-Jones, Teledyne Allvac, Monroe, NC 28110
Electro-slag refining (ESR) is a process used to melt Fe-, Ni-, or Ti- base alloys by passing an electric current through an electrode of the alloy partially immersed in a liquid slag. The liquid slag is maintained at a temperature high enough to melt the end of the electrode by this current. As the electrode melts, a refining action takes place - oxide inclusions are exposed to the slag and are dissolved. Droplets of molten metal fall through the slag and are collected in a liquid metal pool contained in a water-cooled-copper crucible below. By addition of an induction-heated, segmented, water-cooled copper guide tube to the bottom of the crucible, a liquid metal stream can be extracted from the liquid metal pool, rather than allowing it to solidify as an ingot. This stream makes an ideal liquid metal source for: powder atomization, spray deposition, investment casting, melt-spinning, strip casting, and slab casting. Results from a 15 kg/min. pilot-scale system are discussed.
MELTSPINNING OF SiC REINFORCED ALUMINIUM COMPOSITES: L. Katgerman, N. Fei, W.H. Kool, Laboratory of Materials, Delft University of Technology, Delft, The Netherlands
Al MMCs have been prepared by compocasting and subsequent meltspinning. The
effect of rapid solidification process parameters on the microstructure and
particle distribution in the ribbons have been investigated. SiC particles tend
to segregate to the air-side of the ribbons and the segregation effect is
influenced by particle size and volume fraction. Particle pushing models have
been extended with a boundary layer model for fluid flow and heat transfer in
the puddle to give valuable insight into the nature of the SiC segregation.
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