Alsi9cu3 alloy when compared with other degassing techniques. The kinetics of ultrasonic degassing suggests that as the gas is being removed from the liquid, the. The mechanism for ultrasonic argon degassing has been discussed in detail. History, properties and alloys the history of the light metal industry, as that of many other industries in this century, is one of notable and ever accelerating expansion and development. Degassing of aluminum alloys using ultrasonic vibrations. Furthermore, an inherited effect of ultrasonic melt treatment on the.
Information on the casting and working of nonferrous metals and alloys in. Kinetics of cavitation bubble in ultrasonic degassing of. The influence of processing parameters on the ultrasonic. In this work, the combined effect of acoustic cavitation with metal agitation induced by the mechanical vibration of the ultrasonic radiator itself was studied, using a specially designed low frequency mechanical vibrator coupled to the. This chapter focuses on ultrasonic degassing of liquid metals, although much fundamental insight onto the mechanisms and kinetics of ultrasonic degassing has been achieved by experiments using. The present paper reports on the kinetics of ultrasonic degassing and regassing of foundry aluminium alloys and on pilot scale degassing trials. The technology of batch degassing for hydrogen removal. Scientific and practical aspects of ultrasonic treatment of light alloy melts followed with development of acoustic cavitation in liquid metals are discussed.
However, the worldwide most employed process for hydrogen removal from molten aluminum is the inert gas injection by rotating impeller igiri. This paper reports on the kinetics of ultrasonic degassing of an alsi casting alloy. Ultrasonic processing was shown to be an efficient means of aluminum melt degassing with benefits of being. Modeling of the effect of ultrasonic amplitude and. In order to further degas, ultrasonic degassing was adopted. Effects of ultrasonic vibration on degassing of aluminum. The transducer is capable of converting up to 1,2 kw of electric energy at a resonant frequency up to 25 khz. Ultrasonic processing of molten and solidifying aluminum alloys. Pdf effect of ultrasonic melt treatment on degassing and. It is shown, that the ultrasonic melt treatment raises the rate of degassing and fine filtration of light alloy melts and very strongly effects ingot structure. Study on hydrogen removal of az91 alloys using ultrasonic. In 1950 bradfield reported the works of turner on degassing of molten aluminum and its alloys by direct introduction of ultrasonic oscillations into the melt at 15 khz and 26 khz5. The highcost conventional machining of mmcs can be eliminated by nearnet shape manufacturing or by noncontact machining tech niques such as laser processing ref 32 and abrasive waterjet cutting ref 33. Development of a degassing system for aluminium casting.
Changes in the alloy composition can alter the grain size in two ways, by increasing the nucleation rate, and also by causing a decreased rate of crystallization. The results show that ultrasonic vibration has an obvious degassing effect on the. On the other hand, altifecr alloy powders had less adsorbed h 2 o, resulting in the formation of fresh al 2 o 3 above 450 k during vacuum degassing. Effects of ultrasonic vibration on degassing of aluminum alloys article in materials science and engineering a 47312. It is also clear that the kinetics of ultrasonic degassing is timedependently changing as hydrogen is removed from the melt, confirming the results of other researchers 7,10 fig. Degassing in a small melt can be achieved within a few minutes of ultrasonic vibration. Request pdf effects of ultrasonic vibration on degassing of aluminum alloys. The ultrasonic device consists mainly of an ultrasonic generator, a transducer, a horn and a acoustic radiator to transmit ultrasonic vibration to the melt. The efficiency and kinetics of ultrasonic degassing depend on the intensity of ultrasonication. Provide the european light alloys foundries with an environmentally friendly and safe means to improve the quality of their cast parts by applying an ultrasound degassing treatment. Experimental study of ordering kinetics in aluminum alloys. Effect of ultrasonic melt treatment on degassing and structure of aluminium alloys.
Ultrasonic degassing was performed using the equipment shown in figure 1. Degassing treatment of molten aluminum alloys substech. Continuous and static casting with ultrasound new on our ultrasonic metallurgy website. Ultrasonic processing is known to be an efficient means of aluminium melt degassing and structure modification with additional benefits of being economical and environmentally friendly. Efficiency of ultrasonic degassing is compared with. An experimental device which combines the vacuum degassing and ultrasonic degassing has been built in oak ridge national laboratory recently. Ultrasonic processing of molten and solidifying aluminium. Ultrasonic degassing of molten aluminum under reduced. This paper reports on the kinetics of ultrasonic degassing effect of foundry alloys. In the last 10 years the interest to ultrasonic melt processing grew with regard to understanding the underlying mechanisms of previously established effects, developing numerical models of ultrasonic cavitation and the development of nanocomposite technology.
The observed structure factor is in reasonable agreement with previous neutron 6,7 and xray diffraction 8,9 studies of liquid aluminum in the vicinity of the solidi. Degassing, kinetics, aluminum alloys, ultrasonic treatment. Efficiency of ultrasonic degassing is compared with conventional ar rotary degassing. When aluminum and its alloys are melted without a protective cover, oxidation of the melt induces oxide inclusions in the castings. Smartt an innovative process control for rotary degassing of aluminium alloys introduction the production of aluminium castings globally is dominated by the automotive industry and the growing importance of emissions and fuel economy has resulted in a rapid increase in the use of aluminium castings. Dmitry eskin and noe alba baena from brunel university, it has been published at the annual meeting of minerals metals and materials society tms 20 held in san antonio usa, from 3rd to 7th march, 20. Method of accelerating the solution heat treatment and aging kinetics of aluminum alloys disclosure number 201403255 technology summary ornl worked with eck industries, inc. A new approach to ultrasonic degassing to improve the. The removal of hydrogen 2 from molten aluminum with vacuum is based on the equilibrium relationship between the dissolved hydrogen and the hydrogen partial pressure in ambient atmosphere 4 5 6.
Kinetics of ultrasonic degassing of aluminum alloys, proc. Smartt an innovative process control for rotary degassing of aluminum alloys introduction the production of aluminum castings globally is dominated by the automotive industry and the growing importance of emissions and fuel economy has resulted in a rapid increase in the use of aluminum castings. This study focused on two classes of materials aluminum alloys and steelsand demonstrated the application of ultrasonic processing during ingot casting. Ultrasonic degassing of aluminum rests on the diffusion of dissolved hydrogen to cavitation bubbles assisted by their pulsation and their evacuation from the molten metal 7 8 9. Prokic b act2m centre for mechanical and materials technologies, universidade do minho, azurem 4800058 guimaraes, portugal bmp interconsulting, 2400 le locle, switzerland corresponding author. New ultrasonic generator technology for 3d uniformly distributed, ultrasonically assisted metal casting, mixing, forming and ultrasonic degassing of molten aluminum and other nonferrous melts. New trends in aluminium degassing a comparative study. A steel vacuum chamber was built for vacuum degassing with the assistance of ultrasonic vibrations. Aluminum fluxes and degassing methode linkedin slideshare.
To describe the cavitation bubbles movement, traditional rayleighplesset equation was modified. Evaluation of the effect of ultrasonic degassing on. Direct measurements of hydrogen concentration in the melt by foseco alspekh probe are used along with reduced pressure test. May 31, 2017 watch this video of a thermtronix 1,000 pound rotary degassing and fluxing unit for aluminum alloys model autoclean electric shuttle. Kinetics of hydrogen removal from a 10kg charge of an a356type melt for different. There are few people today who are not familiar with at least some modern. Sibley granular fluxes for aluminum alloys, environmental and technological advances, afs fourth international conference on molten aluminum processing, 1995, p 417430 d. Us5344605a method of degassing and solidifying an aluminum. Ultrasonic processing of materials semantic scholar. A suitable ultrasonic degassing apparatus including a novel mmm multifrequency multimode modulated technology, able to supply up to 1. Kinetics of ultrasonic degassing of aluminum alloys. The structure and properties of wrought aluminium alloys series 6xxx with vanadium for automotive industry pages 527532 lechgrega, marzena, phd, eng.
Method of accelerating the solution heat treatment and aging. Degassing operation starts when a flux tablet is plunged by a clean preheated perforated bell to the furnace bottom. In this technique, purge gas is introduced to the melt through a rotating shaft and impeller, or rotor fig. Request pdf kinetics of ultrasonic degassing of aluminum alloys ultrasonic processing was shown to be an efficient means of aluminum melt degassing with benefits of being economical and.
It is found that ultrasonic degassing is effective in reduction porosity as well as to improve the final density of castings. Ultrasonic processing is known to be an efficient means of aluminium melt degassing and structure modification with additional benefits of being economical and environment friendly. Mechanical properties of the degassed az91 alloys are much improved. By testing binary almg alloys cast under regular casting conditions and under the presence of an ultrasonic. Many ultrasonic devices capable of automatic generation of waves. The kinetics is studied through interplay of cavitation bubble generation, melt agitation through acoustic streaming, and flotation of gas bubbles to the surface of the melt. Overview of ultrasonic degassing development springer. The physical mechanism of degassing aluminium alloys through ultrasonic vibration devices is a research area which has been receiving relevant attention over the last few decades ref 1, 8, 9. Effect of ultrasonic degassing on performance of albased. A new approach to ultrasonic degassing to improve the mechanical properties of aluminium alloys h.
Effects of ultrasonic field and vacuum on degassing of molten aluminum alloy. Ultrasonic degassing, an environmentally clean and cheap technique, is an efficient way of degassing in a static volume melt. Ultrasound, degassing, aluminum, hydrogen, cavitation. Establish a link between ultrasonic degassing parameters, melt quality. Many ultrasonic devices capable of automatic generation of waves and integration of different bodies have been developed. Thermtronix 1,000 pound rotary degassing and fluxing unit for. Click here to download manuscript do not upload pdf files at revise.
Vacuum degassing has also been tested as a beneficial and. Sep 19, 2014 solid degassing flux degassing fluxes composed of chlorine and fluorine containing salts are used for degassing molten aluminum alloys. Ultrasonic degassing is compared with rotary impeller. Various methods for introducing sonication in liquid aluminum and magnesium alloys pdf, 873kb. Scientifictechnical information on the casting and working of nonferrous metals and alloys in russian moscow, 1965, no. This paper reports on the kinetics of ultrasonic degassing and re gassing of foundry aluminium alloys and on pilotscale degassing trials. The tensile and fatigue tests were used to evaluate the static and dynamic properties for the different time of ultrasonic degassing, respectively. Rotary degassing of liquid aluminium alloys is a widely used commercial process to control levels of hydrogen, alkali metals and inclusions in the melt prior to casting.
Kinetics of ultrasonic degassing of aluminum alloys springerlink. Ultrasonic degassing is a phenomenon that has been studied since the 1920s and has been used in some industrial or pilotscale applications. Ultrasonic metallurgy improve homogenization and mixing. Effect of vacuum degassing on surface characteristics of. The crucible inside the electric furnace could hold molten aluminum alloys weighing up to 800 g. The di usion of hydrogen bubbles in molten aluminum is predicted, so as to provide examples to illustrate the important. Use of acoustic energy in the processing of molten. Bradfield 1950 reported the works of turner related to degassing of molten aluminum and its alloys by direct introduction of ultrasonic oscillations at 15 and 26 khz into the melt.
The type deals with degassing using power ultrasound alone. Ultrasonic degassing of liquid metals has been studied over the last years, but it has been limited to laboratorial scale experiments of low volumes of melt. The minimum remnant pressure of this vacuum chamber was 50 mtorr. Kinetics of ultrasound degassing of aluminium alloys, written by prof. Smart degassing in aluminium alloys aluminyum alas. Liquid aluminum actively dissolves hydrogen, which forms as a result of chemical reaction with water vapor. Effect of ultrasonic melt treatment on degassing and. Degassing aluminum post by bobs thu dec 23, 2010 4. Aluminium alloy flux degasser tablet manufacturer from vadodara. This article discusses research on using power ultrasound for degassing of molten aluminum alloys. Solubility of gaseous hydrogen falls sharply when aluminum solidifies. Severe regassing was detected by previous experiment on degassing method for aluminiumsilicon alloy by injecting argon with rotation.
Ckco cover flux11 minimizes hydrogen pick up and absorbs as well as collects metallic oxides formed during melting operation. Sep 01, 2015 hydrogen removal of magnesium was first attempted using ultrasonic argon degassing. Kinetics of ultrasonic degassing of aluminum alloys request pdf. Effects of ultrasonic vibration on degassing of aluminum alloys. The influence of processing parameters on the ultrasonic degassing of molten alsi9cu3 aluminium alloy. Mmm multifrequency multimode modulated ultrasonic technology can be used to enhance the process of ultrasonic degassing of molten aluminium during casting. Ultrasonic degassing deaeration, in the case of air is an efficient method of removing dissolved gasses andor entrained gas bubbles from a variety of liquids, including water, candle waxes, aluminum alloy melts, epoxies, silicone oils, adhesives, coating solutions, beverages, polymers, inks, paints, transformer oils, emulsion and suspension products, motor oils and many more. Bradfield 7 reported the works of turner on degassing of molten aluminum and its alloys by direct introduction of ultrasonic oscillations into the meltat 15 khz and 26 khz.
Ultrasonic argon degassing could both remove hydrogen and refine structures. The fundamental reason for ultrasonic degassing is known to be diffusion of dissolved hydrogen to cavitation bubbles assisted by their pulsation, and their subsequent evacuation from the melt. Eisenreich 1950 compared vacuum ultrasonic degassing with vacuum degassing, degassing with chlorine lancing, and sonic and ultrasonic degassing. The main source of gas porosities in aluminium castings is. Degassing effect of ultrasonic vibration in molten melt and. Ultrasonic masterclass presentation ultrasonic vibrations in metallurgy or download as pdf. Ultrasonic degassing of aluminum rests on the diffusion. Severe regassing was detected by previous experiment on degassing method for aluminium silicon alloy by injecting argon with rotation. At least three types of technique have been developed for ultrasonic degassing. Various techniques are available for enhancing the microstructure of aluminium alloys, for instance, there is a strong correlation between grain size and casting temperature. Ultrasonic processing of molten and solidifying aluminum. Degassing of aluminum alloys using ultrasonic vibration. Kinetics of degassing of aluminum powders springerlink. The object is to provide a method of degassing or solidifying an aluminum alloy powder by utilizing an induction heating as a degassing means in a step of forming and solidifying an aluminum powder or aluminum alloy powder, whereby the disadvantages of the prior art can be overcome.
Classic rayleighplesset equation is strongly restricted by the applicable condition that the centre. Accordingly, the formation of fresh al 2 o 3 on the alznmgcuag powder at low temperature of 390 k occurred during vacuum degassing with much h 2 o adsorbed. Parametric studies have been carried out to investigate the efficacy of the ultrasonic degassing of molten aluminum alloy under reduced pressure. In 1950 eisenreich 8 compared vacuum ultrasonic degassing with vacuum degassing, degassing with chlorine lancing, and sonic and ultrasonic degassing. May 01, 2002 rotary impeller degassing, a technique borrowed from the chemical process industry that improves mixing capability, was introduced into aluminum foundries in the mid80s. New trends in aluminium degassinga comparative study. Degassing in a small melt can be achieved within a few. Overview of ultrasonic degassing development brunel university. Ultrasonic melt processing attracts since the 1930 a lot of interest both from academic researchers and industry. Degassing fluxes are commonly shaped in form of tablets. Degassing kinetics aluminum alloys ultrasonic treatment. Ultrasonic degassing of aluminum alloys scientific. A comprehensive theoretical understanding of the kinetics of aluminium degassing has been established in the past twenty years.
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