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. Arc remelting furnace a vacuum arc re melting furnace to produce metal ingots. Abstract to better understand the vacuum arc remelting var process, a 3d finite element model is established to analyzing the electromagnetic, temperature and flow fields of titanium alloy ingot during steady state melting process using ansys software. Var furnaces for melting material that have already been melted and cast into electrodes that are near their full packing density. Nibased super alloys for jet enjine disks and other critical parts, such as 600, 625, 718, and alike are vacuum arc remelted.
Within the var furnace the copper mold is contained by a water jacket. Utilizing procast software, the whole vacuum arc remelting process of highalloy bearing steel ingot the diameter was 160 mm and the high was 600 mm was simulated. A cylindrically shaped, alloy electrode 1 is loaded into the watercooled, copper crucible 2 of a var furnace, the furnace is evacuated, and a dc arc is struck between the electrode cathode and some start material e. Var is the continuous remelting of a consumable electrode by means of an arc under vacuum. 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.
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. Computational modeling of the vacuum arc remelting var. Pdf in this work, a 2d numerical model for the prediction of ingot growth during the vacuum arc remelting process is presented. Vacuum arc remelting furnaces var inductotherm group india. Pdf modeling of the vacuum arc remelting process for. Var skull melter titanium casting titanium casting is increasingly selected as an economical manufacturing method for near net shaped components. Each of the pumping units is switchable individually as well as in series. A multiscale 3d model of the vacuum arc remelting process. The var process has revolutionized the specialty traditional metallurgical techniques industry, and has made possible incredibly controlled materials used in the biomedical. 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. Further, the arc length was optimized to produce and maintain a stable arc during the var process. The most common remelting techniques for nickel alloys are vacuum arc remelting var and electroslag remelting esr. Thermal treatment nitration and oxidation of metals.
Computational modeling of the vacuum arc remelting var process used for the production of ingots of titanium alloys kanchan m. Var vacuum arc remelt matrial for cleanliness specifications. Liquid metal flow behavior during vacuum consumable arc. Vacuum arc remelting furnaces var vacuum aluminum brazing furnaces vab electroslag remelting furnaces esr induction skull melting furnaces ism vacuum induction melting furnaces. Vacuum arc remelting vfe heat treatment industry equipment. Vacuum induction melting and vacuum arc remelting of coal. Patankar1, alec mitchell2, osamu kanou3, nobuo fukada3, kenji suzuki3 1innovative research, inc. A vacuum arc re melting furnace to produce metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications. Arc distribution during the vacuum arc remelting of ti6al4v c. Electroslag remelting esr, also known as electroflux remelting, is a process of remelting and refining steel and other alloys for missioncritical applications in aircraft, thermal power stations, nuclear power plants, military technology, etc the electroslag remelting esr process is used to remelt and refine steels and various superalloys, resulting in highquality ingots. Metal droplets from the electrode drip into a watercooled copper crucible forming an ingot topped by a molten pool 1, as seen in figure 1. Other articles where vacuum arc remelting is discussed. Pdf this paper is devoted to a simple heat model of vacuum arc remelting var including the solution of a nonlinear heat conduction.
State of the art in vacuum arc remelting and electro slag. Vacuum arc re meltingvar is a melting process for production of metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications. A simplified schematic of the process is shown in figure 1. Applications include commercial goods golf clubs, industrial components pump bodies, medical parts implants and of course various components for the aircraft industry. 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. Vacuum arc remelting var is a secondary melting process for production of metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications. Heating is via an electric arc struck between a tungsten electrode and metals placed in a depression crucible in the copper hearth. 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. The advantages of the vader process over vacuum arc remelting are as follows ref 10. In vacuum arc melting the chamber is evacuated and then back filled with argon gas. The intent is to produce a sound ingot with uniform cleanliness and chemical homogeneity. Vacuum arc remelted var billets sandvik materials technology.
Two major mechanical assemblies combine to form the vacuum vessel in which melting occurs the movable furnace head and the fixed melt station. Analyses of the flow and heat transfer phenomena in the var process are presented by bertram 4et al. 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. A consumable titanium electrode is melted by an electric arc into a watercooled tiltable copper crucible. Exposure of molten metal droplets to vacuum reduces free gas content in the steel providing a cleaner product with little segregation. Schematic diagram of the vacuum arc remelting var process courtesy ati allvac, 2003. Consarc utilizes fully computerized controls to optimize reproducibility and ease of operation. Vacuum arc remelting furnaces var products consarc. Hhv has attained the level of expertise in design, developing vacuum technology based equipment, quality in par with the international standards. Modeling of vacuume arc remelting of alloy 718 ingots. Electroslag remelting esr is similar to var, but the steel is remelted in air by a. Introduction vacuum arc remelting var is a process used to control the solidification of segregation sensitive alloys. Rendering of electroslag remelting apparatus and crosssections electroslag remelting esr, also known as electroflux remelting, is a process of remelting and refining steel and other alloys for missioncritical applications in aircraft, thermal power stations, nuclear power plants, military technology, etc.
As in vacuum arc remelting, the metal drops fall into a watercooled copper mold. Vacuum arc remelting var is a process in which an electrode is melted in vacuum by the heat from a dc arc. Since 1963, retech has enjoyed being a worldwide leader in the production of vacuum arc remelt var furnaces designed to melt reactive and refractory metals as well as steel. Jun, 20 vacuum arc melting of magnetic and not magnetic metals, ceramics and minerals. Vacuum induction melting and vacuum arc remelting of coalw. A numerical model of the vacuum arc remelting var process was used to study multistage var processes. 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. Intense heat generated by the arc melts the tip of the electrode while a new ingot is progressively formed below in. Degussa, heraeus and metallgesellschaft hold equal.
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. Pericleous vacuum arc remelting var aims at production of high quality, segregationfree alloys. Four state variables were used to develop a simple statespace model of the var process. Pdf on the modeling of vacuum arc remelting process in. Arc distribution during the vacuum arc remelting of ti6al4v.
The two spinoffs merge to form leybold durferrit gmbh. Vacuum arc remelting process of highalloy bearing steel. Bath temperature, and therefore pool depth, can be very closely controlled. Vacuum arc remelting var and electro slag remelting esr. King, and chris nordlund currently, the temporal distribution of electric arcs across the ingot during vacuum arc remelting var is not a known or monitored process parameter. Vacuum arc remelting furnaces at best price in ahmedabad. Effect of vacuum arc remelting and processing parameters on. This user manual describes the arc habitat suitability index archsi, which is. 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. Vacuum arc remelting is a widely applied vacuum melting process used to control the solidification of segregation sensitive alloys. The primary motivation for characterizing arc motion and distribution inside a var furnace is to. Oxygen and nitrogen in the steel combine,ith impurities and alloying elements.
Remelting occurs under vacuum at a pressure of only approx. With the vast industrial experience in this domain, we are involved in manufacturing and supplying a wide range of vacuum arc remelting furnaces in ahmedabad, gujarat, india. Electroslag remelting esr 22 vacuum arc remelting var 30 electron beam melting eb 36 vacuum investment casting vimic 40 powder metallurgy 46. Accurate control of the electrode gap in a vacuum arc remelting var furnace has been a goal of melters for many years. Vacuum arc remelting furnaces var vacuum aluminum brazing furnaces vab electroslag remelting furnaces esr induction skull melting furnaces ism. The conventional route for manufacturing tialloys, such as ti6v4al, ti10v2al3fe, ti5al5v5mo3cr, as well as pure ti includes double or triple vacuum arc remelting. 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. The relation between arc length and arc voltage during vacuum arc remelting has been established. 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. Vacuum arc remelting furnaces background pioneers in var technology consarc is well known to producers of speciality steel, superalloys, and reactive metals.
Select multiple pdf files and merge them in seconds. Controlling electrode gap during vacuum arc remelting at low melting current. By vacuum arc remelting, billets from ingot cast material or continuously cast blooms are melted under a vacuum atmosphere. Universal stainless offers a wide variety of forging billets. The combination of electric furnace, aod melting and bottom pouring, plus stateoftheart remelting equipment, ensures product that will perform in the most demanding. The studies of low and high power 3xvar confirmed the results of the single stage process studies for ti1023. Pdf numerical simulation of the ingot growth during the vacuum. The size of the electrode gap has a direct influence on ingot solidification structure. The melting workshop was shut down for at least 3 to 4 weeks.
We pioneered commercial ingot production using automated vacuum arc remelting var furnaces. Our standard grade offerings include ef, aod melting, vacuum arc remelting var, and electroslag remelting esr. Multiple input electrode gap control during vacuum arc remelting. Consult alds entire vacuum arc remelting var catalogue on directindustry. Effect of vacuum arc remelting and processing parameters. Electroslag remelting esr 2 points 2 points vacuum arc remelting var 1 point 0. The vacuum arc is a discharge between two metallic electrodes in a vacuum, which is characterized. Purposes of the simulation were to explore the influence of smelting powers on the temperature field, pool shape and solidification. A vacuum arc refers to an electrical discharge between a cathode and an anode at pressures low. In order to meet strict cleanliness specifications, ecfg has the capability to provide vacuum arc remelt var material. 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. 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. 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.
We were the first to apply load cell weighing of electrodes to improve process control. The quality of the produced ingots depends on the operating conditions which could be monitored and analyzed using numerical modelling. The study by hans4 also includes analysis of macrosegregation. Var is widely used to improve the cleanliness and refine the structure of standard airmelted or vacuum induction melted ingots, and then called consumable electrodes. 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. Modern control strategies for vacuum arc remelting of. Segregation development in multiple melt vacuum arc remelting. Vacuum arc remelting is a widely applied vacuum melting process used to control the. Vacuum arc remelting var ald pdf catalogs technical. The transient behavior of the arc was characterized using the external magnetic field and surface current measurements, which were. Vacuum arc remelting var electron beam melting eb vacuum investment casting vimic powder metallurgy.
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. Most vacuum arc remelting of alloy 718 is carried out at ambient gas pressures less than 0. The vacuum arc is a discharge between two metallic electrodes in a vacuum, which is. 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. Fig ure 5 shows the basic design of the vader process with a static crucible.
Vacuum induction melting and casting vimvidp electroslag remelting esr vacuum arc remelting var electron beam melting eb vacuum investment casting vimic powder metallurgy vacuum turbine blade coating ebpvd solar silicon melting and crystallization technology hot isothermal forging hif. Leybold successors merge with heraeushochvakuum gmbh to form leyboldheraeus gmbh. Retech var furnaces can be configured for a range of capacities for producing ingots or castings, from a laboratory scale to many tons, depending on customer requirements. The energy required for melting is created by applying an electric voltage, which generates an arc between the electrode tip and the metal sump below, produced by the molten ingot. Multiple input electrode gap control during vacuum arc. Vacuum arc remelting furnaces var consarc engineering. The main process stages o a consumable var electrode is generated by vim, esr, eb or plasma methods, assembled from titanium sponge, scrap or bulk, or by a prior var melt o dc power is applied to strike an arc between the electrode and the. During the remelting process, a consumable electrode is melted under a vacuum. 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. At the high melting currents 30 to 40 ka typically used for var of segregation insensitive ti and zr alloys, process voltage is used as an indicator of electrode gap, whereas dripshort.
Main modeling challenges for vacuum arc remelting var are briefly highlighted concerning various involving phenomena during the process such as formation and movement of cathode spots on the. When the desired pouring weight in the crucible is obtained, the electrode is quickly retracted and the molten. Pdf a parametric study of the vacuum arc remelting var. Other process parameters such as arc current and fill ratio were also optimized to produce sound and directionally solidified ingots of pure niobium. Vacuum arc remelting furnace, this is a consumable electrode remelting process performed inside a vacuum chamber. Vacuum precision investment casting furnaces vpic vacuum cap furnaces vcap vacuum deoiling furnaces vd vacuum heat treatment vht and brazing furnaces.
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