And moving face quality and moving boundary conditions were added to the simulation. Vacuum duplexinga fresh look at existing melting techniques. Pdf on the modeling of vacuum arc remelting process in. Modern control strategies for vacuum arc remelting of. 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. Pdf calculation of the molten pool depth in vacuum arc remelting. A vacuum arc re melting furnace to produce metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications. 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. 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.
Intense heat generated by the arc melts the tip of the electrode while a new ingot is progressively formed below in. 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. 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. 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. 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. Electroslag remelting esr 2 points 2 points vacuum arc remelting var 1 point 0. 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. Vacuum arc remelting is a widely applied vacuum melting process used to control the. A simplified schematic of the process is shown in figure 1. Vacuum arc remelting process of highalloy bearing steel. Thermal treatment nitration and oxidation of metals. Leybold successors merge with heraeushochvakuum gmbh to form leyboldheraeus gmbh.
Introduction vacuum arc remelting var is a process used to control the solidification of segregation sensitive alloys. The metal density is greather than when applying esr alone. Fig ure 5 shows the basic design of the vader process with a static crucible. Vacuum arc remelted var billets sandvik materials technology.
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. Segregation development in multiple melt vacuum arc remelting. A consumable titanium electrode is melted by an electric arc into a watercooled tiltable copper 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. The var process has revolutionized the specialty traditional metallurgical techniques industry, and has made possible incredibly controlled materials used in the biomedical. When the desired pouring weight in the crucible is obtained, the electrode is quickly retracted and the molten. 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. In vacuum arc melting the chamber is evacuated and then back filled with argon 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. Liquid metal flow behavior during vacuum consumable arc. 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. Four state variables were used to develop a simple statespace model of the var process. Vacuum arc remelting var and electro slag remelting esr. Computational modeling of the vacuum arc remelting var.
Other articles where vacuum arc remelting is discussed. The vacuum arc is a discharge between two metallic electrodes in a vacuum, which is characterized. Electroslag remelting esr 22 vacuum arc remelting var 30 electron beam melting eb 36 vacuum investment casting vimic 40 powder metallurgy 46. The most common remelting techniques for nickel alloys are vacuum arc remelting var and electroslag remelting esr. Arc distribution during the vacuum arc remelting of ti6al4v c. Two major mechanical assemblies combine to form the vacuum vessel in which melting occurs the movable furnace head and the fixed melt station.
A multiscale 3d model of the vacuum arc remelting process. Pdf numerical simulation of the ingot growth during the vacuum. Bath temperature, and therefore pool depth, can be very closely controlled. The studies of low and high power 3xvar confirmed the results of the single stage process studies for ti1023. The advantages of the vader process over vacuum arc remelting are as follows ref 10. State of the art in vacuum arc remelting and electro slag. A numerical model of the vacuum arc remelting var process was used to study multistage var processes. Modeling of vacuume arc remelting of alloy 718 ingots. Purposes of the simulation were to explore the influence of smelting powers on the temperature field, pool shape and solidification. 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 var is a process in which an electrode is melted in vacuum by the heat from a dc arc. Vacuum arc remelting furnaces var inductotherm group india.
Other process parameters such as arc current and fill ratio were also optimized to produce sound and directionally solidified ingots of pure niobium. 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. Pdf this paper is devoted to a simple heat model of vacuum arc remelting var including the solution of a nonlinear heat conduction. The conventional route for manufacturing tialloys, such as ti6v4al, ti10v2al3fe, ti5al5v5mo3cr, as well as pure ti includes double or triple vacuum arc remelting. Degussa, heraeus and metallgesellschaft hold equal. Computational modeling of the vacuum arc remelting var process used for the production of ingots of titanium alloys kanchan m. Schematic diagram of the vacuum arc remelting var process courtesy ati allvac, 2003. Var vacuum arc remelt matrial for cleanliness specifications. The size of the electrode gap has a direct influence on ingot solidification structure. In order to meet strict cleanliness specifications, ecfg has the capability to provide vacuum arc remelt var material. Exposure of molten metal droplets to vacuum reduces free gas content in the steel providing a cleaner product with little segregation. The transient behavior of the arc was characterized using the external magnetic field and surface current measurements, which were.
Vacuum arc remelting furnaces at best price in ahmedabad. Effect of vacuum arc remelting and processing parameters on. Most vacuum arc remelting of alloy 718 is carried out at ambient gas pressures less than 0. Pdf a parametric study of the vacuum arc remelting var. Vacuum arc remelting var ald pdf catalogs technical. 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. Select multiple pdf files and merge them in seconds. Nibased super alloys for jet enjine disks and other critical parts, such as 600, 625, 718, and alike are vacuum arc remelted. Vacuum arc remelting furnaces var consarc engineering. The combination of electric furnace, aod melting and bottom pouring, plus stateoftheart remelting equipment, ensures product that will perform in the most demanding. Pericleous vacuum arc remelting var aims at production of high quality, segregationfree alloys. The intent is to produce a sound ingot with uniform cleanliness and chemical homogeneity.
We were the first to apply load cell weighing of electrodes to improve process control. Vacuum precision investment casting furnaces vpic vacuum cap furnaces vcap vacuum deoiling furnaces vd vacuum heat treatment vht and brazing furnaces. Applications include commercial goods golf clubs, industrial components pump bodies, medical parts implants and of course various components for the aircraft industry. 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. 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 var electron beam melting eb vacuum investment casting vimic powder metallurgy. Var skull melter titanium casting titanium casting is increasingly selected as an economical manufacturing method for near net shaped components. Vacuum arc re meltingvar is a melting process for production of metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications.
We pioneered commercial ingot production using automated vacuum arc remelting var furnaces. 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 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 secondary melting process for production of metal ingots with elevated chemical and mechanical homogeneity for highly demanding applications. The melting workshop was shut down for at least 3 to 4 weeks. 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 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. 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. 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. 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. Vacuum induction melting and vacuum arc remelting of coalw. 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.
This user manual describes the arc habitat suitability index archsi, which is. Consarc utilizes fully computerized controls to optimize reproducibility and ease of operation. Vacuum arc remelting furnaces var vacuum aluminum brazing furnaces vab electroslag remelting furnaces esr induction skull melting furnaces ism vacuum induction melting furnaces. Remelting occurs under vacuum at a pressure of only approx. A vacuum arc refers to an electrical discharge between a cathode and an anode at pressures low. Consult alds entire vacuum arc remelting var catalogue on directindustry. As in vacuum arc remelting, the metal drops fall into a watercooled copper mold. Pdf modeling of the vacuum arc remelting process for. The relation between arc length and arc voltage during vacuum arc remelting has been established.
The two spinoffs merge to form leybold durferrit gmbh. Heating is via an electric arc struck between a tungsten electrode and metals placed in a depression crucible in the copper hearth. 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. 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. 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. The study by hans4 also includes analysis of macrosegregation. 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. Vacuum arc remelting is a widely applied vacuum melting process used to control the solidification of segregation sensitive alloys. Oxygen and nitrogen in the steel combine,ith impurities and alloying elements.
The vacuum arc is a discharge between two metallic electrodes in a vacuum, which is. Patankar1, alec mitchell2, osamu kanou3, nobuo fukada3, kenji suzuki3 1innovative research, inc. 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. Within the var furnace the copper mold is contained by a water jacket. 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. Multiple input electrode gap control during vacuum arc remelting. 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. Vacuum arc remelting vfe heat treatment industry equipment. Vacuum induction melting and vacuum arc remelting of coal. Vacuum arc remelting furnaces var vacuum aluminum brazing furnaces vab electroslag remelting furnaces esr induction skull melting furnaces ism. Arc distribution during the vacuum arc remelting of ti6al4v. The quality of the produced ingots depends on the operating conditions which could be monitored and analyzed using numerical modelling. 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.
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. During the remelting process, a consumable electrode is melted under a vacuum. Effect of vacuum arc remelting and processing parameters. Universal stainless offers a wide variety of forging billets.
Multiple input electrode gap control during vacuum arc. Each of the pumping units is switchable individually as well as in series. 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. Accurate control of the electrode gap in a vacuum arc remelting var furnace has been a goal of melters for many years.
By vacuum arc remelting, billets from ingot cast material or continuously cast blooms are melted under a vacuum atmosphere. Degussa, heraeus and metallgesellschaft hold equal interests in leyboldheraeus gmbh. Controlling electrode gap during vacuum arc remelting at low melting current. Jun, 20 vacuum arc melting of magnetic and not magnetic metals, ceramics and minerals. Arc remelting furnace a vacuum arc re melting furnace to produce metal ingots. Further, the arc length was optimized to produce and maintain a stable arc during the var process. Electroslag remelting esr is similar to var, but the steel is remelted in air by a. Analyses of the flow and heat transfer phenomena in the var process are presented by bertram 4et al. 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. 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.
202 611 250 1567 627 784 687 1424 650 1564 617 572 165 1080 1349 1483 415 341 593 396 115 1306 992 183 1446 1069 981 322 494 959 249 1236 495 469 127 1040 970 273 5 1122 322 237 1331 1462 1212 826 489 319 1071 1296