Coreless induction melting conference weighs technology gains, foundry practices.Coreless Induction Melting Conference Weighs Technology Gains, Foundry Practices After a particularly interesting, but involved session on furnace refractory lining techniques, furnace design and the different methods of charging a furnace, a young metal shop foreman was heard to remark, "It sure ain't like making bread!" The young foundryman's comment said a great deal about the nature of the AFS A distributed file system for large, widely dispersed Unix and Windows networks from Transarc Corporation, now part of IBM. It is noted for its ease of administration and expandability and stems from Carnegie-Mellon's Andrew File System. AFS - Andrew File System Conference, "Coreless Induction Melting of Steel," held recently in Cincinnati. The conference, coordinated by Ezra Kotzin and Ian Kay Ian Kay (born in 1967, UK), is a convicted murderer, known as the "Woolworths Killer", and notable for committing an attack which cost the infamous serial killer Peter Sutcliffe the use of one eye. , was organized by the Coreless Induction Furnace An induction furnace is an electrical furnace in which the heat is applied by induction heating of a conductive medium (usually a metal) in a crucible around which water-cooled magnetic coils are wound. Committee (8-C) of AFS. The committee's chairman, Kenneth W. Copi, reported that the successful three-day meeting was the first one to encompass a weekend, also including commercial displays as an integral part of the conference. In his opening remarks, Dr. John Dr. John (also Dr. John Creaux) is the stage name of Malcolm John Rebennack Jr. (born November 21, 1940), a colorful pianist, singer, and songwriter, whose music spans, and often combines, blues, boogie woogie, and rock and roll. M. Svoboda, Center for Metals Production, said that the growth in the use of coreless induction melting has been a major factor contributing to the technological improvements in quality and productivity experienced by steel foundries in recent years. Svoboda said that, although most steel foundries use coreless furnaces simply to melt a given alloy in the shortest time, a trend is underway to use the induction furnace as a refining vessel. He cited three examples of emerging coreless induction melting technologies that will propel the use of this steelmaking technique even faster in the near future. They include liquid metal refining, the Calidus system and vacuum processing. Liquid Metal Refining (LMR LMR Land Mobile Radio LMR Labor-Management Relations LMR Last Minute Resistance LMR Living Marine Resources LMR Longmoor Military Railway (UK) LMR Liquid-Metal Reactor LMR Laser Magnetic Resonance ) This process, developed by the Steel Casting Steel casting is a manufacturing process in which molten metal is poured into a mold, allowed to solidify within the mold, and then the mold is broken and the solid piece is taken out. Research and Trade Association (SCRATA), uses a stainless steel stainless steel: see steel. stainless steel Any of a family of alloy steels usually containing 10–30% chromium. The presence of chromium, together with low carbon content, gives remarkable resistance to corrosion and heat. ladle placed within an induction coil See inductor. Induction coil A device for producing a high-voltage alternating current or high-voltage pulses from a low-voltage direct current. The largest modern use of the induction coil is in the ignition system of internal combustion engines, such as . The heated ladle is fitted with a slide gate pouring system and a porous plug for the introduction of inert gas inert gas or noble gas, any of the elements in Group 18 of the periodic table. In order of increasing atomic number they are: helium, neon, argon, krypton, xenon, and radon. . Svoboda noted that a two-ton pilot facility has proven capable of consistently providing a highly-refined steel heat and holding it effectively for up to 1 1/2 hours. Teaming an induction furnace with a direct arc furnace would allow a foundry the production latitude to supply metal on a semi-continuous basis rather than in batches. The Calidus System This system is similar to that described above. Developed in Sweden, it uses a nonconducting ladle shell made of an epoxy-fiberglass composite material which slips into a stationary induction coil. After completing the melt process, the ladle is lifted from the coil and used to pour castings. Used for the production of highly refined steel, the present composite ladle shell is costly and still relatively fragile for most foundry environments. Vacuum Processing A melting trend that is rapidly gaining momentum, vacuum processing is reportedly growing at a 14% annual rate and is expected to capture 50% of the induction furnace market by the year 2000. The principal benefits of vacuum processing are low hydrogen content and the promotion of deoxidation deoxidation the removal of oxygen from a chemical compound. with carbon under low pressure to provide gaseous deoxidation products rather than potential inclusions. Not new, but not widely used in the U.S. because of its relatively high cost, the growing clamor for "cleaner" steels seems to be tilting the steel foundry industry in the direction of vacuum production. The importance and diversity of refractories proved to be of considerable interest to conference attendees. Interest was expressed in the most common types of monolithic refractories used for coreless induction production of steel such as the dry vibratables, damp ramming mixes, plastics, castables and patching compounds. Though prefired crucibles, brick and special shapes also were discussed, interest was highest in linings having a single uninterrupted, or so-called monolithic, surface. The most used refractory is the dry vibratable type, a ground material, moisture free, and mechanically vibrated into place around a form. Advantages of dry vibratable linings are many. Because they contain no moisture, they can be installed and sintered sin·ter n. 1. Geology A chemical sediment or crust, as of porous silica, deposited by a mineral spring. 2. A mass formed by sintering. v. sin·tered, sin·ter·ing, sin·ters v. in a relatively short period of time; they are subject to unique phase sintering sintering, process of forming objects from a metal powder by heating the powder at a temperature below its melting point. In the production of small metal objects it is often not practical to cast them. , from complete ceramic sintering at the hot face to very little sintering at the cold face, to better guard against crack propagation through the entire lining. In addition, they have longer shelf life than lining materials containing water and are easier to install and remove. Dry vibratable refractories have some shortcomings A shortcoming is a character flaw. Shortcomings may also be:
A new furnace lining must be burned-in using a controlled temperature rise to force a chemical reaction in lining material. Furnace temperature rise and hold times before charging garnered several opinions; however, it was widely agreed that proper heating during initial sinter sinter Mineral deposit with a porous or vesicular texture (having small cavities). Siliceous sinter is a deposit of opaline or amorphous silica that occurs as an incrustation around hot springs and geysers and sometimes forms conical mounds (geyser cones) or terraces. will maximize bond formation, increase density and lining strength. Conversely, rushing a furnace into production definitely reduces the life of a refractory lining, resulting in general metal saturation, cracking during thermal cycling and increased refractory wear. PHOTO : Ian Kay, Cast Metals Institute, far left, welcomes international attendees to the Coreless PHOTO : Induction Melting of Steel Conference. They included, from Kay's left to right, Yoshiya PHOTO : Suzuki, Suzuka Furnace Co/Div of Fuji Electric, Japan; Carlos Luzcano and Dr. Ignacio PHOTO : Elcoro, both of Hylsa, Monterey, Mexico; Jim Thiessen, Sutherland Steel Foundry, PHOTO : Saskatchewan, Canada; Maseo Tateno, also from Suzuka Furnace Co; and Hiroo Ikeda, Nippon PHOTO : Crucible Co, Osaka, Japan. Tom Bex/Senior Editor |
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