Energy-Efficient System of Feedstock Transport Operating in a System of Particulate Material Forming Press Compact Sintering Furnace

Transcription

1 Energy-Efficient System of Feestock Transport Operating in a System of Particulate Material Forming Press Compact Sintering Furnace R. Moszumański Astract Compare to casting an plastic forming of soli feestock, the manufacture of machine parts from particulate materials is relatively less common, an this fact is mainly ue to the generally prevailing opinion that power metallurgy consumes large volumes of energy. An innovative solution to this prolem is the recently evelope energy-efficient system of feestock transport. It comprises a heat transfer system operating uring transport of col presse compacts an hot sintere proucts etween the press an the furnace, an a system of force energy recovery uring proper sintering. Uner moel conitions, empirical stuies were conucte to examine time-relate temperature variations in green compacts an heat treate proucts, to check next uner real conitions the temperature istriution in these items. The possiility of using the newly evelope solution in most of the alreay operating systems with only minor moernising work an proper organisation of the prouction process was state. Inex Terms particulate materials, force energy recovery, col presse compacts, hot sintere proucts R I. INTRODUCTION ELATIVELY small scale of the use of the process of making machine parts from particulate materials (PM), compare with the casting technique an plastic forming of soli feestock, is largely ue to the generally prevailing opinion aout its high energy-intensity. No one seems to consier the simple an ovious fact that the metallurgical process of spraying molten metal with liqui or gas, omitting numerous operations of plastic forming y rolling or extrusion, is alreay sufficient to think of PM as offering large energy savings. We all know that heat treatment or thermo-chemical treatment of soli materials consumes a lot of energy, an yet it iscourages no one from using it. Sintering of compacts shape in close ies is nothing else ut a variation of the heat treatment. The suject of research an evelopment works was the technique of making machine parts with special properties an complex shapes from the presse an sintere particulate materials, using knowlege recently acquire aout the system incluing technological equipment, tooling an workpieces [7], [8]. The main ojective of the stuies was to remove the major ostacles to further progress in the technique of making proucts from powers presse an sintere, such as the lack of presses with riven ie tales, R. Moszumanski is with the Mechanical Engineering Department, Cracow University of Technology, POLAND, rysmos@mech.pk.eu.pl the lack of special tools incluing ies, punches, an cores, an also the lack of traine personnel who woul e ale to perform all the operations relate with the manufacture of compacts characterise y intricate shapes an special properties. All these ostacles have a historical ackgroun, while unreasonaly high price of particulate materials is another negative sie effect of the relatively low popularity of this technique in the engineering inustry. More wiesprea use of moern presses for powere proucts is expecte to help in the removal of the aove mentione ostacles an in enhancing the evelopment of the manufacturing technique commonly known as power metallurgy, consiering its inisputaly unique character, an in competitive cases - high performance an low material consumption [9], [10]. The expecte immeasurale effect is reaking arriers to a wie issemination of the technology of making proucts from the presse powere materials as an alternative in some cases to casting or plastic forming of soli feestock. The technology ase on loose powers is waste-free, an if appropriate technical culture is achieve it can e consiere clean technology. The applie innovative pulsatory technique allows making high-ensity compacts, reucing at the same time the compression force an, consequently, the unit pressure on tools an the energy intensity of the process [11], [12]. Thermal energy savings uring the recuperative ackwar sintering, which is also an original metho for consoliation of the green compact structure y heat treatment, is the suject of this article. II. PROTECTED SOLUTIONS Transport of green compacts from the press into the furnace is carrie out iniviually in the case of large components, while meium-size items are place on flat transport pallets, an small items in ceramic oxes. In tunnel furnace, compacts are travelling on a moving enless gri structure; compacts resting on pallets are pushe forwar y a elt conveyor. For large proucts an high temperatures, trolleys running on rails uner the furnace are use [1], [2], [3] [et al.]. Feestock is heate an coole in the successive zones of the furnace, while the resiual heat is usually lost. A positive example of the practical use of the high temperature of the sintere proucts is forging operation of selecte metallic materials. Various solutions are also

2 known which utilise waste heat for rying of wet shape ferrite or ceramic locks [4], [5], [6] [et al.]. The propose technical solution of comprehensive heat recovery inclues in the first stage an energy-efficient system of feestock transport (Fig. 1), which ensures heat transfer etween the col compacts an hot sintere proucts uring their movement in a press - furnace arrangement [13]. Fig. 2. Schematic representation of energy recovery in an air-tight, ackwar-type, pusher tunnel furnace [14] Fig. 1. Schematic representation of the energy-efficient system of feestock transport operating in a press-furnace arrangement [13] The invention allows rational management of the thermal an electrical energy uring feestock transport from the press to the furnace achieve through special arrangement of the transport route an loa lifting evices. Conveyors are place in the main part of the system uner the furnace, which enales minimising the overall imensions. The essence of the energy-efficient system of feestock transport operating in a press-furnace arrangement consists in the recovery of thermal energy y convection heat transfer etween the heat-treate proucts leaving the tunnel furnace an presse green compacts entering the furnace. High reliaility of movement was otaine y the use of transport pallets in a pusher tunnel furnace [14]. III. MODEL STADIES To verify the correctness of the initial assumptions regaring the energy-efficient system of feestock transport operating in a press-furnace arrangement, moel tests were mae to stuy heat transfer etween the heat treate proucts leaving the tunnel furnace an green compacts shape y pressing. For this purpose, a moel conveyor was esigne an constructe. It comprises an outer calorimeter chamer (Fig. 3) consisting of an inner rigi ceramic hollow oy insulate with a layer of thermo-insulating material esigne for operation at a temperature of up to 5000C, aitionally encase on the outsie with ceramic ricks. The secon an the main step in this comprehensive heat recovery system takes place in oth outer sections of the tunnel furnace (Fig. 2). A system of force energy recovery was use uring sintering of compacts in a ackwar-type furnace. The invention comprises a thermal energy recovery system with simultaneous separation of the waste vapour in an air-tight, ackwar-type, pusher tunnel furnace without the nee for transverse holes mae in the furnace tunnel, which can cause amage to thermal insulation. The essence of the thermal energy recovery system consists in the use of collective ventilation mae in the tunnel founation, connecte with perforate elts on which perforate pallets are moving. Fig. 3. Moel of energy recovery uring feestock transport in a press - furnace arrangement

3 The chamer has a lower shelf on which the transport pallet with the heat treate proucts is place an a top shelf for the palette with green compacts. The chamer is equippe with a twin-track system to measure the temperature of cooling proucts an preheate compacts. Before the pallet with the representative prouct is place in the outer calorimeter chamer, it is preheate in a laoratory chamer furnace to a temperature of 4000C, while palette with the compact is left at room temperature. To escrie the time-relate temperature variations uner the aove mentione moel conitions, approximation equation (1) in the form given elow was use: y a xc 1 e (1) In a moel of the transport system, at threefol repeataility of measurements, uner conitions corresponing to the conitions existing in a press-furnace arrangement, the time-relate temperature variations were etermine for the heat treate representative prouct which, together with pallet, was giving off the heat (Fig. 4, curve 1) an for the shape green compact which, together with palette, was taking in the heat (Fig. 4, curve 2). To verify the correctness of the initial assumptions for energy recovery in an air-tight, ackwar-type, pusher tunnel furnace, moel tests were mae to stuy heat transfer etween the heat-treate proucts leaving the intermeiate section of a tunnel furnace an green compacts preheate in the feestock transport system operating in a press furnace arrangement. For this purpose, a moel of the en section of the furnace was esigne in the form of an inner calorimeter chamer (Fig. 5) consisting of an inner rigi ceramic hollow oy insulate with a layer of thermo-insulating material esigne for operation at a temperature of up to 6000C, aitionally encase on the outsie with ceramic ricks. The chamer has a left shelf for a elt carrying the transport pallet with heat treate proucts an a right shelf for a elt carrying the palette with preheate green compacts. Uner the shelves there is a channel with a lower riven y a DC motor. The chamer is equippe with a twin-track system to measure the temperature of cooling proucts an preheate compacts. Before the elt an the pallet with the representative prouct are place in the inner calorimeter chamer, they are preheate in a laoratory chamer furnace to a temperature of 5000C, while the elt an the pallet with compact are preheate to a temperature of 2000C. Fig. 4. Time-relate temperature variations in the moel feestock transport system operating in a press-furnace arrangement Curve 1 representing proucts cooling uner moel conitions is escrie y approximation equation (1) with the following coefficients: a = 239,59632, = 286,95697, c = 4, , = - 61, while curve 2 representing the time-relate temperature variations in compacts preheate uner moel conitions is escrie y approximation equation (1) with the following coefficients: a = - 2, , = 153,6575, c = 86,491546, = 48, Fig. 5. Moel of energy recovery uring feestock transport in an air-tight, ackwar-type, pusher tunnel furnace To escrie the time-relate temperature variations uner the aove mentione moel conitions, approximation equation (2) in the form given elow was use: y a xc 1 e (2) In a moel of the outer furnace section, at threefol repeataility of measurements, uner the conitions of free air flow corresponing to the conitions existing in an airtight, ackwar-type, pusher tunnel furnace, the time-relate temperature variations were etermine for the heat treate proucts which, together with palette, were giving off the heat (Fig. 6, curve 3) an for the preheate green compacts which, together with palette, were taking in the heat (Fig. 6, curve 4).

4 A lower was next switche on an, at threefol repeataility of measurements, uner the conitions of force air circulation, the same variations were etermine for the heat treate proucts which, together with palette, were giving off the heat (Fig. 6, curve 5), an for the preheate green compacts which, together with palette, were taking in the heat (Fig. 6, curve 6). IV. TESTING UNDER REAL CONDITIONS To confirm the correctness of the initial assumptions regaring the energy-efficient system of feestock transport operating in a press-furnace arrangement, tests were mae uner real conitions to stuy heat transfer etween the heat-treate proucts leaving the tunnel furnace an green compacts shape y pressing. For this purpose, a conveyor place uner the heating tunnel of special testing evice was use (Fig. 7). The conveyor was equippe with a twin-track system to measure the temperature of cooling proucts an preheate compacts. Fig. 6. Time-relate temperature variations in the moel tunnel of an airtight, ackwar-type, pusher tunnel furnace Curve 3 representing the heat treate proucts cooling uner moel conitions in free air flow is escrie y a = 394,80192, = 108,08828, c = 49,526787, = -16, while curve 4 representing the green compacts preheate uner moel conitions in free air flow is escrie y a = 160,56229, = 148,369, c = 10, = 26, Curve 5 representing the heat treate proucts cooling uner moel conitions in force air flow is escrie y a = 193,28549, = 82,706987, c = 24,47728, = 20, Fig. 7. Energy recovery uring feestock transport in a press-furnace arrangement To escrie the temperature istriution uner real conitions, approximation equation (3) in the form given elow was use: y a 1 e xc In the feestock transport system operating in a pressfurnace arrangement, at threefol repeataility of measurements, real temperature istriution in the furnace was etermine for the heat treate proucts which, together with palette, were giving off the heat (Fig. 8, curve 7) an for the shape green compacts which, together with palette, were taking in the heat (Fig. 8, curve 8). (3) while curve 6 representing the green compacts preheate uner moel conitions in force air flow is escrie y a = 343,18094, = 243,31283, c = 18,231266, = -33, Fig. 8. Temperature istriution uring feestock transport in a pressfurnace arrangement

5 Curve 7 representing proucts cooling uner real conitions is escrie y approximation equation (3) with the following coefficients: a = 77,638671, = 753,39864, c = 10,951072, = 2, while curve 8 representing the time-relate temperature variations in compacts preheate uner real conitions is escrie y approximation equation (3) with the following coefficients: which, together with palette, were giving off the heat (Fig. 10, curve 9) an for the preheate green compacts which, together with palette, were taking in the heat (Fig. 10, curve 10). Blowers were next switche on an, at threefol repeataility of measurements, uner the conitions of force air flow, the temperature istriution was etermine for the heat treate proucts which, together with palette, were giving off the heat (Fig. 10, curve 11) an for the preheate green compacts which, together with palette, were taking in the heat (Fig. 10, curve 12). a = - 99,281134, = 1402,0148, c = 15,891508, = 4, To confirm the correctness of the initial assumptions for energy recovery in an air-tight, ackwar-type, pusher tunnel furnace, tests were mae uner real conitions to stuy heat transfer etween the heat-treate proucts leaving the intermeiate section of a tunnel furnace an green compacts preheate in the feestock transport system operating in a press-furnace arrangement. For this purpose, the heating tunnel of special testing evice was use (Fig. 9). The tunnel was equippe with a twin-track system to measure the temperature of cooling proucts an preheate compacts. Fig. 10. Temperature istriution in the feestock in heat transfer section Curve 9 representing the heat treate proucts cooling uner real conitions in free air flow is escrie y a = 369,61385, = 134,75151, c = 8, , = -0, while curve 10 representing the green compacts preheate uner real conitions in free air flow is escrie y a = 171,82951, = 1342,0811, c = 5,725909, = -1, Fig. 9. Energy recovery uring feestock transport in heat transfer section To escrie temperature istriution uner the aove mentione real conitions, approximation equation (4) in the form given elow was use: y a xc 1 e (4) In the outer section of an air-tight, ackwar-type, pusher tunnel furnace, at threefol repeataility of measurements, uner the conitions of free air flow, the temperature istriution was etermine for the heat-treate proucts Curve 11 representing the heat treate proucts cooling uner real conitions in force air flow is escrie y a = 211,96307, = 406,45021, c = 7, , = -0, while curve 12 representing the green compacts preheate uner real conitions in force air flow is escrie y a = 307,83154, = 193,05679, c = 8, , = -0,

6 V. CONCLUSION Earlier it was reporte that the use of pulsating pressure uring pressing of compacts reuces y 27% the maximum compression force necessary to achieve the ensity close to soli material an what is particularly important - it reuces y up to 45% the force necessary for compact ejection from the forming tool. In oth these areas, a significant reuction in the consumption of electrical energy was also reporte [13], [14]. Currently it has een estalishe that final recuperative sintering in an atmosphere of air, carrie out to otain the final feestock structure consoliation, can reuce the thermal energy consumption y two-stage heat recovery, an owing to this it can also reuce the consumption of electrical energy, thus removing the so far existing ostacles to a more wie-sprea use of the PM process [15], [16]. REFERENCES [1] Z. Song, et al. The homogeneity of sintering in moern ceramic tunnel kiln: Taoci Gongcheng, Fuel an Energy Astracts, 1998 [2] E. Fresnel, Tunnel kiln with infrare elements, PCT/FR2000/002348, [3] M. Sato, et al. Tunnel kiln for ceramic sintering, IEEE International Conference on Plasma Science, 2002 [4] S. Toshiaki, et al. Preheating evice an preheating metho for scrap, JP [5] W. Hasselmann, Tunnel furnace for the temperature treatment of goos, Nr [6] F. Meng, J. Wan, H. Li, Theoretical an numerical analysis of waste heat utilization evice for coal gangue rick tunnel kiln, Avance Materials Research, , 2011 [7] R. Moszumański, Offer for companies Know-how of the art of manufacturing machinery parts with special properties an complex shapes from the presse an sintere particulate materials: technological machines - tools workpieces, National Research an Development Centre, Warsaw 2012 [8] R. Moszumański, et al., Report of the research - evelopment project No. N R , Centre for Training an Quality Systems Organisation, Cracow University of Technology, Krakow 2012 (unpulishe) [9] R. Moszumański, Moelling of loose material particles ehaviour in chaotic an orere state, ProTechMa 2012, International Scientific Conference, Transfer Inovácií XX/2012, Herlany 2012 [10] R. Moszumański, Functions of research oject of the process of quasistatic an pulse caliration of the sintere compacts of groun materials Progressive Technologies An Materials In Mechanical Engineering Pro-Tech-Ma 2013, Rzeszów 2013 [11] R. Moszumański, M. Moszumański, Sintering of particulate materials an tools in a protective atmosphere, 11th Ieroamerican Congress of Mechanical Engineering Buenos Aires 2013 (unpulishe) [12] R. Moszumański, Tools to manufacture thin-walle components from particulate materials y a ynamic metho, Progressive Technologies an Materials in Mechanical Engineering Pro-Tech- Ma 2014, Hutnik. (accepte for pulication). [13] R. Moszumański, S. Knapik, J. Kryza, A. Taor, Energy-efficient feestock transport system in a press furnace arrangement, Polish Patent Office, Warsaw 2013 [14] R. Moszumański, J. Kryza, S. Knapik, A. Taor, A system for the energy recovery an vapour separation in an air-tight, ackwar-type, pusher tunnel furnace, Polish Patent Office, Warsaw 2013 [15] R. Moszumański, M. Moszumański, A versatile metho an evice to enhance the particulate material pressing process with mechanical virations, P Polish Patent Office, Warsaw 2013 [16] R. Moszumański, S. Knapik, J. Kryza, Automate metho an apparatus for ynamic manufacturing of thin-walle components from particulate materials, P Polish Patent Office, Warsaw 2013