Eric schlienger materials processing department sandia national laboratories albuquerque, new mexico 87 18. Vacuum arc remelting process during var vacuum furnace, an electric arc is struck at the tip of an air melted ingot known as an electrode, melting the material within the vacuum container. Vacuum arc remelting var ald is one of the leading suppliers of vacuum melting furnace technologies for engineered metals var is widely used to improve. We pioneered commercial ingot production using automated vacuum arc remelting var furnaces. An introduction to premium melting carpenter technology. Vacuum metallurgy and vacuum induction melting secowarwick. Vacuum casting faction fixture can be added as optional. Vacuum induction melting and vacuum arc remelting of coalwx gammaprime superalloys erin t. Since 2006, as a result of strategic acquisition of retech, we offer our customers worldwide a comprehensive solution in the field of melting furnaces. Vacuum arc melting processes for biomedical niti shape memory alloy article pdf available in matec web of conferences 30.
A cylinder type consumable electrode produced with vacuum induction melting vim, is placed into a cylindrically enclosed copper crucible cooled by a water jacket. Us4450570a vacuum arc melting and casting furnace with a. Since 2006, as a result of strategic acquisition of retech, we offer our customers. In order to meet strict cleanliness specifications, ecfg has the capability to provide vacuum arc remelt var material. Modeling of the vacuum arc remelting process for estimation and control of the liquid pool profile article pdf available in journal of dynamic systems measurement and control 63. Pdf vacuum arc melting processes for biomedical niti. Var in the vacuum arc remelting var furnace, the dc electric current is passed through the electrode. Nonetheless, conventional recycling routes exhibit a very limited refining potential with regard to oxygen contamination.
Vacuum arc remelting furnace, this is a consumable electrode remelting process performed inside a vacuum chamber. Heating is via an electric arc struck between a tungsten electrode and metals placed in a depression crucible in the copper hearth. Aug 10, 2004 vacuum arc remelting var is a process used throughout the specialty metals industry to control casting of segregationsensitive and reactive metal alloy ingots. Thermal treatment nitration and oxidation of metals. Vacuum metallurgy involves designing and supplying systems and processes for treating metallic materials in liquid form particularly vacuum systems for the melting, casting and remelting of metals and alloys, metals for solar cells as well as special coating equipment for. Pdf modeling of the vacuum arc remelting process for estimation. Some advantages and limita tions of the competing vacuum processes are given in table 1.
During var vacuum furnace, an electric arc is struck at the tip of an air melted ingot known as an electrode, melting the material within the vacuum container. Var vacuum arc remelt matrial for cleanliness specifications. Vacuum arc melting of magnetic and not magnetic metals, ceramics and minerals. Vacuum induction melting ten 6 kilogram 300 pound heats of merl 76 see table 1 for merl 76 chemistry were produced by vacuum induction table 1. Pdf this study primarily involved using a vacuum arc remelting var process to prepare a nitinol shapememory alloy with distinct ratios of alloy.
Vacuum arc remelting is a casting process where a consumable electrode is melted under vacuum at a carefully controlled rate using heat generated by an electric arc struck between the electrode and the ingot. The fixed melt station, the lower half of the vacuum vessel, consists of a removable copper crucible that is placed into a fixed stainless steel water jacket and guide. Compared to air melting processes such electric arc furnaces eaf with argon oxygen decarburization aod converters, vim of superalloys provides a considerable reduction in oxygen and nitrogen contents. Of particular importance in the former group are nickelbase superalloys such as alloy 718, commonly used for forged rotating parts in the hot stages of jet aircraft engines and. This current connection consists of a fixed contact and of a cooperating contact arranged on the bottom of the crucible and movable with the tilting crucible.
Melting under high vacuum lowers the levels of dissolved oxygen, oxide inclusions, hydrogen, nitrogen, and elements having a high vapour pressure, such as lead, manganese, and tin. By vacuum arc remelting, billets from ingot cast material or continuously cast blooms are melted under a vacuum atmosphere. The most common remelting techniques for nickel alloys are vacuum arc remelting var and electroslag remelting esr. Vacuum arc remelting furnaces background pioneers in var technology consarc is well known to producers of speciality steel, superalloys, and reactive metals. The invention concerns a vacuum arc melting and casting furnace comprising a vacuum chamber, a tilting crucible and a current connection leading to the bottom of the tilting crucible. From the electronics industry to the aerospace industry, our alloys have been used for wide ranging applications. Vacuum arc remelting var is the process of melting an electrode under vacuum by passing an electric arc between the electrode and the base of the mold and resolidifying into an ingot in a cooled mold. The arc is struck between the two horizontal elec trodes that are to be melted. Vacuum arc remelting var is the principal secondary melting process used to produce ingots for almost all wrought alloy 718 applications. E karapanou, ag lekatou, ak sfikas, e georgatis, k lentzaris and ae karantzalis2017 vacuum arc melting processed feal matrix based intermetallic composites, reinforced with vc phases.
Our selection of arc melting furnaces is low cost, compact, simple to operate and reliable, yet can reach temperatures up to 3700c and find use in a wide range of applications. Pdf vacuum arc melting processes for biomedical niti shape. Overall, the goal of the process is to increase the homogeneity and purity within the formed ingot. Vacuum induction melting is indispensable in the manufacture of superalloys. Vacuum metallurgical equipment is manufactured in our facilities in the united states, poland and china, which are the regions with the highest demand for highmelting and foundry technologies. Exposure of molten metal droplets to vacuum reduces free gas content in the steel providing a cleaner product with little segregation. We were the first to apply load cell weighing of electrodes to improve process control. As the melting electrode drips into the bottom of the vessel, the surface area of each falling drip is exposed to the environment of the vacuum, which. We will attempt, with this paper, to summarize our previous work along with other unpublished work as it applies to var of alloy 718. Vacuum melting and remelting processes asm international. Tial based alloys find, read and cite all the research you need on researchgate.
Vacuum arc remelting is a widely applied vacuum melting process used to control the solidification of segregation sensitive alloys. Vacuum metallurgical equipment is manufactured in our facilities in the united states, poland and china, which are the regions with the highest demand for high melting and foundry technologies. Coalw alloys strengthened with the l1 2 gammaprime phase have promise as next generation high. Vacuum arc remelting var is a process used throughout the specialty metals industry to control casting of segregationsensitive and reactive metal alloy ingots. The arc melter operates under a partial pressure of inert gas, usually argon, to avoid atmospheric contamination during melting.
Vacuum arc remelting var is another secondary refining process that enhances the quality of metal that had undergone primary air melting andor was melted. Vacuum arc remelting var ald is one of the leading suppliers of vacuum melting furnace technologies for engineered metals var is widely used to improve the cleanliness and refine the structure of standard airmelted or vacuum induction melted ingots called consumable electrodes. Additional information on some of these processes is available in. Vacuum arc melter accelerated maturation of materials camm.
Var vacuum arc remelting 11 vacuum system intecos vacuum system is designed for utmost flexibility and minimized pump down times, which can be achieved by one threestage mechanical pumping unit and, for fine vacuum, one oil booster ejection unit. Arc melting furnaces materials research furnaces, llc. The watercooled ram extends through a vacuum seal in the head and the electrode clamps to its lower extremity thus becoming the cathode of the arc melting. Pdf vacuum arc remelting var is an industrial metallurgical process widely used throughout the specialty metals industry to cast large alloy ingots find. Four state variables were used to develop a simple statespace model of the var process. One of the major focuses is on melting of titanium alloys. Vacuum arc remelting var spang power electronics is a manufacturer of custom power equipment installed throughout the var industry for the refining of steels, superalloys, titanium, and zirconium. The var process has revolutionized the specialty traditional metallurgical techniques industry, and has made possible incredibly controlled materials used in the biomedical, aviation, and aerospace fields. Shrinkage cavitypiping at the end of the solidified ingot of steels is one of the most common casting problem in 316l austenitic stainless steel ingot, when consumable electrode is melted and cast in a watercooled copper mould by vacuum arc remelting furnace. Pdf consolidation of compacted zircaloy chips via vacuum.
Compact vacuum arc melting system with 7 cavities eqsp. Vacuum arc behavior a vacuum arc refers to an electrical discharge between a cathode and an anode at pressures low enough that the conduction path is sustained by vaporization and ionization of the electrode rather than the ambient gas. As the melting electrode drips into the bottom of the vessel, the surface area of each falling drip is exposed to the environment of the vacuum, which removes any residual gases from the alloy. Arc distribution during the vacuum arc remelting of ti6al4v. Applications of finite element modeling on vacuum arc. Each of the pumping units is switchable individually as well as in series. It is an excellent tool for smelting metal alloys for phase diagram research. Vacuum arc remelting is the continuous remelting of a consumable electrode by means of an electric dc arc between the electrode and the base of a copper mold.
Carpenter technology corporation premium melting 3 three types of premium melting furnaces generally used to produce highperformance specialty alloys in wrought forms are vacuum induction melting vim, electroslag remelting esr and vacuum arc remelting var furnaces. Modern control strategies for vacuum arc remelting of. Since there is an accompanying vacuum system capable of pressures less than 10 mtorr, a simple procedure of evacuating and backfilling, with the inert gas, can ensure the relative purity of the inert atmosphere. Var steels and specialalloys, as well as titanium and zirconium and their alloys, are used in a large number of high integrity applications, where cleanliness, homogeneity and improved fatigue properties in the final product are essential. Vacuum induction melting and vacuum arc remelting of coal. Us3190949a vacuum arc melting furnace with crucible. Within the var furnace the copper mold is contained by a water jacket. This paper describes process modeling applications of vacuum arc remelting var and plasma arc melting pam.
Crystal growth furnaces materials research furnaces, llc. The var process has revolutionized the specialty traditional metallurgical techniques industry, and has made possible incredibly controlled materials used in the biomedical. Pdf modeling of the vacuum arc remelting process for. Vacuum induction melting vim furnaces are often the starting point in. Vacuum arc melting furnace with crucible changing apparatus filed dec. The first furnace, resembling furnaces in operation today, was built by vonbolten in 1903 noesen 1967. O melting of reactive metals titanium, zirconium and their alloys for aero space, chemical industry, offshore technique and reactor technique 12 ton var furnace from ald vacuum arc remelting var ald is one of the leading suppliers of vacuum melting furnace technologies for engineered metals. Vacuum arc melting processed feal matrix ased intermetallic. In present study an effort has been made to reduce the size of shrinkage cavity piping by establishing the optimum value of hot. Compact vacuum arc melting system with 7 cavities eqspmsm207. Vacuum metallurgy involves designing and supplying systems and processes for treating metallic materials in liquid form particularly vacuum systems for the melting, casting and remelting of metals and alloys, metals for solar cells as well as special coating equipment for turbine blades. Var steels and superalloys as well as titanium and zirconium and its alloys are used in a great number of high. A builtin mechanical manipulator is included for tilting and rotating metal ingots for the re melting process.
The melting current, in flowing between the electrode and the mold, passes through the arc, liquid pool, and solidified strand. I vacuum keg meeting furynge w ith crucibije changing apparatus 3 sheetssheet 3 filed 221, 1 960 7. A builtin mechanical manipulator is included for tilting and rotating metal ingots for the remelting process. Var steels and superalloys as well as titanium and zirconium. Electroslag remelting esr is similar to var, but the steel is. Intense heat generated by the arc melts the tip of the electrode while a new ingot is progressively formed below in. Furnace steel conference, pittsburgh, december 1957. Vacuum melting services vacuum induction melting vacuum. Jun, 20 vacuum arc melting of magnetic and not magnetic metals, ceramics and minerals. Consolidation of compacted zircaloy chips via vacuum arc melting analysis of the electric arc. Vacuum arc remelting var is a secondary melting process for production of metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications.
Vacuum melting services from a few grams to 500 lbs. Whatever your application or the size of your project, the focus we give to cleanliness, detail and process control are the keys to producing our high purity specialty alloys. Both techniques are consumable electrode melting processes in which the heat is generated by an electric arc between the ingot electrode cast from the primary melting process and some type of base plate located at the bottom of. Ingots produced by air melting, esr, vim, and ebm are utilized as electrodes in the. The vacuum arc remelting process is extensively utilized in the commercial production of ti6al4v ingots. Compared to airmelting processes such electric arc furnaces eaf with argon oxygen decarburization aod converters, vim of superalloys provides a considerable reduction in oxygen and. Vacuum arc remelting var ald pdf catalogs technical. Vacuum arc remelting is the continuous remelting of a consumable electrode by means of an electric dc arc between the electrode and the base of a. In this process, employed for casting steels that contain easily oxidized alloying elements, a consumable electrode made of forged steel or of compacted powder or sponge is continuously melted by an arc under vacuum. Arc melting furnaces use an electric arc to heat or melt material and are a cost saving alternative to induction or resistance heater furnaces for certain applications.
Modern control strategies for vacuum arc remelting of segregation sensitive alloys rodney l. Mcdevitta ati specialty materials, 2020 ashcraft ave. Assessment of microstructure, sliding wear and aqueous corrosion response. Modelbased control of the vacuum arc remelting process. Vacuum arc remelting of alloy 718 semantic scholar. Metallirgy of the vacuum arc remelting process the var ingots solidification structure ot a given matriel h o fundion of the locof solidf.
For var, various process parameters could be analyzed using commercial modeling software to determine the best solution to resolve different types of problems, such as alloy. Evaluation of deoxidization techniques during vacuum. As in vacuum arc remelting, the metal drops fall into a watercooled copper mold. Eqspmsm207 is a compact vacuum arc melting furnace with a nonconsumable tungsten electrode and watercooled copper crucibles. One example for this is selective melting away of the shelf resulting in fallin material that later becomes a defect site. Vacuum induction melting furnaces for more information visit. It is most commonly the final liquid metal processing step before forging. Mathabathe and others published coldpressing and vacuum arc melting of. In vacuum arc melting the chamber is evacuated and then back filled with argon gas. Vacuum arc refining var is a secondary melting process that allows ingot structure, homogeneity and cleanliness to improve.
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