This study primarily involved using a vacuum arc remelting var process to prepare a nitinol shapememory alloy with distinct ratios of alloy components nitinol. Findings pursuant to the iran freedom and counterproliferation act ifca of 2012. Electroslag remelting uses highly reactive slags calcium fluoride, lime, alumina, or other oxides are usually the main components to reduce the amount of typea sulfide present in biometal alloys. Experimental investigation, metallurgical and materials transactions a on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Vacuum arc remelting furnace is widely used to improve the cleanliness and. 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. Esr reduces other types of inclusions as well, and is seen as an alternative to the vacuum arc. With the objective of this study, cobalt free low nickel newly developed maraging steel and a new grade of. Consarc utilizes fully computerized controls to optimize reproducibility and ease of operation. Vacuum arc remelting casting handbooks asm international. Vacuum arc remelting is melting done under a vacuum.
Vacuum arc remelting furnaces var products consarc. The quality of the produced ingots depends on the operating conditions which could be monitored and analyzed using numerical modelling. 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. The two processes combined now have an annual world production approaching 0. By vacuum arc remelting, billets from ingot cast material or continuously cast blooms are melted under a vacuum atmosphere.
Fig ure 5 shows the basic design of the vader process with a static crucible. We pioneered commercial ingot production using automated vacuum arc remelting var furnaces. Vacuum arc remelting var ald pdf catalogs technical. A consumable titanium electrode is melted by an electric arc into a watercooled tiltable copper crucible. All elements of the process including the electrode, vacuum, titaniumbased. This paper describes process modeling applications of vacuum arc remelting var and plasma arc melting pam. Drops of the molten electrode metal pass through the slag layer to form a layer of metal underneath.
On the modeling of vacuum arc remelting process in titanium alloys view the table of contents for this issue, or go to the journal homepage for more 2016 iop conf. O melting of reactive metals titanium, zirconium and. Pericleous vacuum arc remelting var aims at production of high quality, segregation free alloys. The vacuum arc remelting var process is widely used to improve the. Vacuum arc remelting furnaces background pioneers in var technology consarc is well known to producers of speciality steel, superalloys, and reactive metals. The first furnace, resembling furnaces in operation today, was built by vonbolten in 1903 noesen 1967. 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 arc remelting 1 pm vacuum arc remelting 2 electroslag refining 1 casting 2. Electroslag remelting furnaces esr multiple electrode electroslag remelting furnaces. Vacuum metallurgy this 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. Vacuum arc remelting furnaces var vacuum arc remelting furnaces. Modern control strategies for vacuum arc remelting of. Its used for alloying elements that oxidise easily. 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.
Vacuum metallurgy this 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. Proceedings of the th world conference on titanium. 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. For the manufacture of special products, refining and solidification processes are often combined. Vacuum precision investment casting furnaces vpic vacuum cap furnaces vcap vacuum deoiling furnaces vd vacuum heat treatment vht and brazing furnaces. In order to meet strict cleanliness specifications, ecfg has the capability to provide vacuum arc remelt var material. This article illustrates the var process and the capabilities and variables of the var process. Vacuum arc remelting furnaces var inductotherm group.
Vacuum arc remelting furnaces var var furnaces are used for melting material that have already been melted and cast into electrodes that are near their full packing density. Pdf this study primarily involved using a vacuum arc remelting var process to prepare a nitinol. Main modeling challenges for vacuum arc remelting var are briefly. Introduction general metallurgical aspects of vacuum treatment var technology other vacuum arc melting and remelting technologies comparison with other remelting technologies summary and conclusions references.
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. The melting of the electrode material is modelled with an enthalpyporosity approach. Vacuum arc remelting furnace, this is a consumable electrode remelting process performed inside a vacuum chamber. Pdf modeling of the vacuum arc remelting process for. Vacuum arc melting of magnetic and not magnetic metals, ceramics and minerals. Consult alds entire vacuum arc remelting var catalogue on directindustry.
Var steels and superalloys as well as titanium and zirconium and its alloys are used in a great number of high. An introduction to premium melting many alloys contain elements like aluminum and titanium which, when heated, react with. Vacuum arc remelting var is a secondary melting process for production of metal ingots with. Exposure of molten metal droplets to vacuum reduces free gas content in the steel providing a cleaner product with little segregation. Electroslag remelting article about electroslag remelting. Mar 28, 2002 read treering formation during vacuum arc remelting of inconel 718. Melting, remelting, and casting for clean steel campbell. Var technology can refine the ingot structure in titanium alloy smelting and improve the purity of the product.
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. 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. 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. Vacuum arc remelting var is a process used to control the solidification of segregation sensitive alloys. Pdf on the modeling of vacuum arc remelting process in. 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. Vacuum arc remelting furnaces var products inductotherm. A parametric study of the vacuum arc remelting var process.
It slowly melts and drips through a slag and a new ingot is built up underneath. For titanium alloy melting, gap lengths are on the order of a few centimeters. 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. 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. Reactive var furnaces rvar induction skull melting furnaces ism two chamber vertical induction. The transient behavior of the arc was characterized using the external magnetic field and surface current measurements, which were. Among the different refining processes such as vacuum arc remelting, electron beam remelting, plasma arc remelting and electroslag remelting, electroslag remelting esr process is considered as the most distinguished secondary refining process due to its reality, economical production cost, low needed investments, system with. Custom furnaces in laboratory scale or for the production of unusual. Vacuum arc remelting furnaces var vacuum aluminum brazing furnaces vab electroslag remelting furnaces esr. A simplified schematic of the process is shown in figure 1. A multiscale 3d model of the vacuum arc remelting process.
Jun, 20 vacuum arc melting of magnetic and not magnetic metals, ceramics and minerals. Four state variables were used to develop a simple statespace model of the var process. Spang power electronics is a manufacturer of custom power equipment installed throughout the var industry for the refining of steels, superalloys, titanium, and zirconium. Vacuum arc remelting var metalwerks vacuum arc remelt var furnaces have an extensive range of capabilities. Mar 15, 20 a threedimensional, transient, multiscale model of the var process is presented, allowing novel simulations of the influence of fluctuations in arc behavior on the flow and heat transfer in the molten pool and the effect this has on the microstructure and defects.
Nowadays, the vacuum arc remelting var process is effectively utilized to manufacture titaniumbased alloys. Vacuum arc remelting vacuum arc remelting var is another secondary refining process that enhances the quality of metal that had undergone primary air melting andor was melted, or remelted, in arc, vim or esr furnaces. Pdf vacuum arc remelting var is an industrial metallurgical process widely used. Vacuum arc and electroslag remelting process metal and. Electroslag remelting esr is a secondary refining process used to further refine many alloys. The var process has revolutionized the specialty traditional metallurgical techniques industry, and has made possible incredibly controlled materials used in the. Read treering formation during vacuum arc remelting of inconel 718. Arc distribution during the vacuum arc remelting of ti6al4v. 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 melting furnaces materials research furnaces, llc.
The vacuum arc remelting var process is widely used to improve the cleanliness and refine the structure of standard air melted or vacuum induction melted vim ingots and also used in the triplex production of superalloys. 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 segregation and shrinkage pipe. Pdf modeling of the vacuum arc remelting process for estimation. Vacuum arc remelting furnaces var vacuum aluminum brazing furnaces vab electroslag remelting furnaces esr induction skull melting furnaces ism vacuum induction melting furnaces. The positions and in turn distribution of arcs is not directly controlled, and arcs are free.
The var feedstock is consumable electrodes produced by vim or conventional air melting. A threedimensional, transient, multiscale model of the var process is presented, allowing novel simulations of the influence of fluctuations in arc behavior on the flow and heat transfer in the molten pool and the effect this has on the microstructure and defects. Because of titaniums high affinity for oxygen, melting and casting of this highly reactive material must be done under vacuum. The production of materials which are free from detrimental segregation has long demanded the use of the remelting processes of vacuum arc remelting var and electroslag remelting esr. During electroslag remelting, the temperature of the slag, which consists of various components caf 2, cao, sio 2, al 2 o 3, and others, exceeds 2500c. The most common remelting techniques for nickel alloys are vacuum arc remelting var and electroslag remelting esr. 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. Vacuum arc remelting vfe heat treatment industry equipment. Remelting variations under vacuum apart from the remelting of a consumable electrode in a watercooled copper crucible, there is a recent development of the vacuum arc remelting process, namely vacuum arc double electrode remelting vader. Pdf vacuum arc melting processes for biomedical niti shape.
Vacuum arc remelting is a widely applied vacuum melting process used to control the solidification of segregation sensitive alloys. Vacuum arc remelting furnaces var furnaces for melting material that have already been melted and cast into electrodes that are near their full packing density. The primary motivation for characterizing arc motion and distribution inside a var furnace is to identify and then eventually maintain a desired spatial energy profile so as to ensure a high quality ingot. Lots of uses for alloys made in this way in the airline industry. A comprehensive cfd model is proposed to study the interaction between various transport phenomena flow, heat, etc. In the esr process you take an ingot and pass an electric current through it. Ingots produced by air melting, esr, vim, and ebm are utilized as electrodes in the. Electromagnetic cold crucible furnaces emcc electromagnetic cold crucible. Vacuum arc remelted var billets sandvik materials technology.
Thermal treatment nitration and oxidation of metals. Among the different refining processes such as vacuum arc remelting, electron beam remelting, plasma arc remelting and electroslag remelting, electroslag remelting esr process is considered as the most distinguished. On the other hand, the investments in stateoftheart technology such as pressure electro slag remelting pesr, vacuum induction melting vim and vacuum arc remelting var are the result of research showing a real need for a new generation of steels. I recently got the opportunity to visit a company the produce vacuum arc melting furnaces and many other vacuum related. Electroslag remelting esr in this process, there is a slowly melting consumable electrode and a watercooled mold for solidification, as in vacuum arc remelting, but the melting is conducted under normal atmosphere and is accomplished by a thick, superheated layer of slag on top of the shallow metal pool. In the industrial production of titainum and titanium alloys, the most commonly used techniques are vacuum arc remelting var and cold hearth melting. The processes can be preceded by vacuum induction melting vim to make up an. Pdf vacuum arc melting processes for biomedical niti. Vacuum ingot pouring is often employed to produce very large ingots that are subsequently processed, in expensive forging and machining operations, into such products as rotors for power generators. We were the first to apply load cell weighing of electrodes to improve process control.
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