Rezaei3 1 institute of advanced technologies for metallic materials, tarbiat modares university, tehran, iran. An improved electroslag refining esr flux composition and process for making same are shown. Effect of slag on inclusions during electroslag remelting. Evaluation of the electroslag remelting process in medical.
Cast electrodes of commercial aluminum were electroslag refined using kclnaclna 3 alf 6 slag containing na 2 b 4 o 7. It is also found that the ductility, impact toughness and. If you need to print pages from this book, we recommend downloading it as a pdf. Production and refining of metals electrolytic c25. The refined metal droplets are collected in a cold hearth apparatus. Another timesaving benefit of the essc process stems from the electroslag refining that occurs when the molten metal passes through the slag bath.
Applies to electroheat installations for remelting and, in some cases, for refining processes of metals through direct resistance heating of a conductive slag. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. The electroslag melting process page 214 unt digital. The esr technology is of interest not only for the production of smaller weight ingots of tool steels and. The best electroslag remelting results are obtained with. An analysis on formation of anf6 electroslag fluxes skin. Flux 37s is used together with strip electrodes of the cr. Increasing demands for ultrahighstrength steels in commercial as well as military applications have raised interest in finding alternatives to the highcost highalloyed steel and superalloys currently used, e. Electroslag remelting 2 20 ton esr furnace capable of melting under protective atmosphere. Figure 1 shows a schematic diagram of the esr process that uses a stationary.
Many factors influence the nonmetallic inclusions in electroslag steel including furnace atmosphere and inclusions content in the consumable electrode, slag amount and its composition, power input, melting rate, filling ratio, and so on. Us3857702a electroslag refining flux compositions and. Esr has been known since the 1930s, but it took approx. Zero shear force is applied to the free surface of slag. Electroslag remelting its status, mechanism and refining. Strip cladding has been around for decades, and historically, submerged arc strip cladding sasc has been the most commonly used process, offering deposition rates of about 33 pounds per hour. The electroslag remelting process esr 3 premelted electroflux 4. Electroslag strip cladding also offers greater deposition rates about 55 pounds per hour, compared to the 33 pounds per hour typically offered with submerged arc strip cladding. Much higher levels of nitrogen can be achieved due to the pressure applied above the slag which can be increased significantly above normal atmospheric. Electroslagwelding was derived from a metal manufacturing process called electroslag remelting or refining esr. Report of the committee on electroslag remelting and plasma. Electroslag melting and refining linkedin slideshare. Dry copper rods were dipped into the slag pool from the top for collecting slag samples, maintaining precaution to avoid short.
Apparatus for electroslag or arc remelting of metals definition statement this place covers. The molten steel in form of both liquid film on the electrode tip and descending droplets contacts with the slag and get refined due to desulfurization and removal of nonmetallic inclusions sulfides and oxides. Electroslag refining of crnimowmnv ultrahighstrength steel. Pdf electroslag refining of crnimowmnv ultrahighstrength steel.
The method, which significantly increases the quality of the metals and alloys produced, was. 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. Electroslag strip cladding offers productivity and cost. Refining reactions in applying the electroslag remelting technique successfully to superalloys an understanding of the potential re actions and refining mechanisms, is necessary, these may be divided for convenience into flotation or mechani cal removal and chemical and electro chemical reactions. A method of electroslag refining of metal is taught.
The pressure electroslag remelting process is a recent advancement and allows for the manufacture of new high nitrogen alloys with unique properties under pressures of several atmospheres. Electroslag melting experience for reactive metals, base. Nitrogen dissolves in the molten slag either in the form of free nitride n3. The molten metal in the form if droplets is refined as it passes through the molten slag. The resulting improvements in the efficiency and performance of the process established consarc as the leading manufacturer of esr systems worldwide. Cr 2 o 3 was also added to the molten slag at specified instants after start of refining, as a means of additional chromium input. Computational modeling, electroslag remelting, esr, superalloy ingots. Important basic mechanisms such as electrochemistry, thermochemistry, and heat transport are described. The main difference is that the arc is started between the electrode tip and the bottom of the part to be welded. A method of forming an ingot of refined metal by the electroslag refining process comprises the steps of introducing into the lower open end of a cooled mould a solid uncooled electricallyconductive member of a material weldably compatible with the metal to be refined, the member having a surface area sufficient to conduct the full working current employed in the process.
Companies all around the world prefer to use the highquality electroflux. After the molten slag reaches the tip of the electrode, the arc is extinguished. Esrrefined material is free from shrinkholes and isotropic and is. The chemical homogeneity of the ingots was established by xray fluorescence, plasma scan and spectrovac methods. Iron reduction in aluminum by electroslag refining. This report is based upon the electroslag refining esr operations undertaken by the commonwealth steel company, waratah, nsw, and draws upon detailed technical records of both production and experimental operations over an extended period. The method starts with the introduction of unrefined metal into an electroslag refining process in which the unrefined metal is first melted at the upper surface of the refining slag. Test methods for electroslag remelting furnaces are specified in iec 60779. Coldstarting techniques for use with the experimental electroslagrefining furnace at mrl have been examined. During my last three years at university, there was only one other person doing metallurgy in my year, and that was a person called charles gheenen. The pressure electroslag remelting process pesr total. The watercooled copper mold provides relatively high gradient of temperature resulting in. Electro slag remelting esr ald vacuum technologies.
After passing through the flux, the alloy slowly cools down and solidifies again into a remelted ingot 1, 2, 3,4,5. For his thesis he decided to do some work at professor dilewijns laboratory, which involved working on the new electroslag refining esr equipment they had acquired in their offsite. The electroslag refining esr process is one of the most important secondary refining processes owing to its relatively low production cost, low capital investment and ability to produce high quality steel with desired chemistry and homogenous structure. Computational modeling of the electroslag remelting esr. Experimental results indicate that the iron content decreases with increasing na 2 b 4 o 7 addition and remelting time, and the iron content decreases from 0. Electroslag remelting as an efficient way to increase the quality of alloy for. The effect of electroslag refining on iron reduction from commercial aluminum was investigated. In this work the yield of alloying elements and the removal. Metallurgical characteristics of electroslagrefined mdn. Flux for electroslag welding sandvik 37s se811 81 sandviken sweden march 2005 general description sandvik 37s is a highly basic, agglomerated flux for electroslag strip surfacing. General processes of refining or remelting of metals. The kinetic behavior of phosphorus transfer was investigated during electroslag remelting esr of g20crni2mo bearing steel. Other articles where electroslag remelting is discussed.
Electroslag remelting furnaces in the 1960s consarcs engineers conceived a new approach to electroslag remelting, quite different from others in use at the time. This bulletin traces the development of the electroslag melting process from its modest beginnings to the present. Esw is similar to electrogas welding, but the main difference is the arc starts in a different location. Influencing the electroslag remelting process by varying. Electroslag welding esw is a highly productive, single pass welding process for thick greater than 25 mm up to about 300 mm materials in a vertical or close to vertical position. Diverse methods for refining metals in liquid state c22b 9003 c22b 9106. Electroslagwelding is a process providing one of the highest weld deposition rates and is therefore most costeffective for suitable applications its unique capability permits to weld in one pass groove joint of two plates, thick 1 to 12 inches 25 to 300 mm and more. Two coldstarting devices based on exothermic reactions and resistanceheating, respectively, have both been developed to the stage where reliable starting can be achieved. Electroslagwelding, cost effective vertical one pass. An electric arc is initially struck by wire that is fed into the desired weld location and then flux is added. The instant esr flux compositions are made from particulate batch materials providing at least alumina, a fluoride and alkaline earth metal oxide, including calcium oxide, by the process described to yield a product exhibiting a substantially uniform fusion characteristic and to be substantially free. Influencing the electroslag remelting process by varying fluorine content of the utilized slag proceedings of emc 2015 1. Metals free fulltext kinetics of phosphorus transfer during. Electroslag remelting esr can effectively improve the cleanliness and compactness.
Since the choice of flux is a unique parameter in the electroslag process, two chapters are developed to this subject. Esrrefined material is free from shrink holes and isotropic and is. The electroslag refining process esr is a variant of the group of consumable electrode remelting processes esr, var, ebr and par for producing ingots of higher quality than that of the original material by means of controlled solidification and chemical refining. The electroslag remelting process esr is important because it provides better control of the solidification. Based on more than forty years of experience with both processes, deutsche edelstahlwerke have excellent knowhow and process engineering in place, which is optimally adapted to. Electroslag welding esw applications are similar to electrogas welding. Barrancos mooney pdf cladding electroslga typically a very continuous operation that requires high amperages and high duty cycles. Fluoride containing slag, which influences the nonmetallic inclusions to a great extent, has been widely used for the electroslag remelting process. The droplets enters the molten steel pool, bottom of which is progressively solidifying. Use of electroslag refining for novel insitu alloying. Remelting materials for purpose of refinining c22b 916 c22b 9228. Unfortunately, this book cant be printed from the openbook. It gives excellent slag removal and bead appearance also for nballoyed strip electrodes.
Electroslag remelting an electrometallurgical process in which a metal in the form of a consumable electrode is remelted in a bath of an electrically conducting synthetic slag by the action of heat released upon the passage of electric current through the slag. Esr electroslag remelting is the abbreviated name given to electroslag consumable electrode remelting and secondary refining process. The electroslag melting process page 12 unt digital. Pdf the electroslag remelting process esr is important because it provides better. It is also used to describe three separate processes, using the principle of electroslag namely i consumable electrode metal refining and cost structure improvement process ii the semicontinuous or 11.
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