Дисертації з теми "Steel alloys Heat treatment"
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Anderson, Danny. "Effect of the joint addition of aluminum and molybdenum on the precipitation and recrystallization in HSLA steels." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66207.
Повний текст джерелаBradley, Christopher Michael. "Microstructural characterization and heat treatment of A-286 turbine buckets." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
Повний текст джерелаWang, Xiaolan. "The effects of rust on the gas carburization of AISI 8620 steel." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-073108-094449/.
Повний текст джерелаCerully, Laura B. "The fabrication of thin-walled steel alloys through the gas carburization of reduced metal oxide extrusions." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34809.
Повний текст джерелаDalai, Biswajit. "Microstructure and Properties of Solid-State Additively Processed Alloy 600 Claddings on 304L Stainless Steel." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1542724808933024.
Повний текст джерелаQuan, Liang. "Using FDM and FEM to simulate the decarburization in AISI 1074 during heat processing and its impact." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44769.
Повний текст джерелаDai, Tao Dai. "Effect of Postweld Heat Treatment on the Properties of Steel Clad with Alloy 625 for Petrochemical Applications." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523572474171801.
Повний текст джерелаMaropoulos, S. "The effect of heat treatment on structure-property relationships in a low alloy Ni-Cr-Mo-V steel." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370954.
Повний текст джерелаDoležal, Petr. "Vlastnosti nízkolegovaných ocelí za snížených teplot." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231635.
Повний текст джерелаFrom, Malin, Johanna Ejerhed, Artin Fattah, Markus Lindén, and Alex Karlstens. "Heat Resistant Steel Alloys : Atlas Copco." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256662.
Повний текст джерелаCochet, Julien. "Conception optimisée et comportement en service de manilles forgées." Thesis, Lorient, 2016. http://www.theses.fr/2016LORIS241.
Повний текст джерелаShackles used for the assembly or the mooring of petroleum platforms require constantly higher mechanical properties. But the manufacturing defects often lead to premature failure which can cost 1M€/day. Thus, in order to understand and anticipate those manufacturing defects, three numerical tools have been developed to simulate (i) the manufacturing process, (ii) the heat treatment and (iii) the mechanical behavior of the shackle. A shackle is manufactured via a sequence of hot forming stages and the manufacturing process has been characterized during all the stages, with measures of temperature, geometry and loads. The numerical thermo-mechanical model has been developed in 3D and gives a very good prediction of each forging parameters. A numerical study of influence of some process parameters has led to a better understanding of scrapping. Temperature measurements, metallographic observations as well as mechanical testing have been carried out on cylindrical rods after various heat treatment cycles. The numerical heat treatment model has been developed in 1D and predicts phase transformations during normalizing and quenching, as well as the hardness at each point of the rod. Finally, the distribution of the mechanical properties over a shackle has been characterized and the deformation modes of the shackle were evaluated via a load test on a dedicated bench. The numerical model of the shackle under tension has been developed in 3D and allows to evaluate the working load limit, the break load as well as the critical zone of the shackle
Forte, Julio Faria da Silva. "Modelagem e otimização de experimentos para o tratamento térmico de recozimento: um estudo com o algoritmo simulated annealing." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=4380.
Повний текст джерелаThis dissertation presents a study for experiments modeling applied for a heat treatment industrial process. The driving force to this work have raised from usual difficulties while low-alloy steels annealing industrial processes get on, trying to find out temperatures which the superficial hardness measurements reaches low values enough and suitable for the following stages, in special focus, the machining. At the first time, some experiments have been done with several steel grades, where superficial hardness is achieved as a function by annealing temperature, percent carbon content and percent silicon content of the samples. There was purposed a quadratic model for modeling the hardness as a function of that three parameters. The parameter estimation of the purposed model was done by the simulated annealing algorithm, a metaheuristic for global optimization which can be as the same as annealing of a solid material. Starting at the purposed model, the inverse problem was solved, where the estimated annealing temperature was achieved by the carbon and silicon percent contents and the suitable hardness.
Tavitas-Medrano, Francisco Javier. "Artificial aging treatments of 319-type aluminium alloys." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103299.
Повний текст джерелаWalker, Jacob D. "Heat Transfer Analysis of Localized Heat-Treatment for Grade 91 Steel." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6045.
Повний текст джерелаBhatti, A. R. "Effect of heat treatment on metallic glasses." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236306.
Повний текст джерелаSjölander, Emma. "Heat treatment of Al-Si-Cu-Mg casting alloys." Doctoral thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Material och tillverkning – Gjutning, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-15695.
Повний текст джерелаHilty, Eric. "Influence of Welding and Heat Treatment on Aluminum Alloys." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1396877051.
Повний текст джерелаKing, Benjamin. "Welding and post weld heat treatment of 2.25%Cr-1%Mo steel." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060404.095844/index.html.
Повний текст джерелаMartin, D. C. (David Charles). "Selected heat conduction problems in thermomechanical treatment of steel." Doctoral thesis, Oulun yliopisto, 2011. http://urn.fi/urn:isbn:9789514295195.
Повний текст джерелаTiivistelmä Väitöstyössä tutkitaan kahta ongelmaa liittyen hiiliteräksen termomekaanisen käsittelyn numeeriseen mallintamiseen. Työssä tarkastellaan teräksessä tapahtuvaa lämmönsiirtoa ja faasimuutoksia jäähdytyksen aikana, eli ensisijaisen tärkeitä ilmiöitä kehittynyttä teräksen valmistusta ja prosessointia ajatellen. Ensimmäisenä ongelmana tutkitaan epälineaarisen energiayhtälön muodostaminen huomioiden teräksen termofysikaaliset materiaaliominaisuudet, diffuusion kontrolloimat ja diffuusiosta riippumattomat irreversiibelit faasimuutokset. Lisäksi huomioidaan näiden väliset kytkennät. Yhtälöt ratkaistaan numeerisesti ja käytetyt menetelmät esitellään differenssimenetelmien ja diagonaalisesti implisiittisten Runge-Kutta-menetelmien osalta. Väitöstyössä näiden käyttöä havainnollistetaan simuloimalla niukkahiilisen teräksen käyttäytymistä teollisia olosuhteita vastaavan jäähdytyksen aikana. Laskentatulokset osoittavat ratkaisumenetelmän suunnittelun ja valinnan tärkeyden erityisesti silloin, kun lämmönjohtuminen, mikrorakenteen kehittyminen ja termofysikaaliset materiaaliominaisuudet muuttavat ratkaistavan ongelman epälineaariseksi ja jäykäksi. Toisena ongelmana tutkitaan edellä esitetyn lämmönsiirtomallin käyttöä osanainversioanalyysiä. Laboratoriokokeiden, termopareilla suoritettujen lämpötilamittausten, työssä kehitetyn lämmönsiirtomallin ja suoritetun inversioanalyysin avulla rekonstruoidaan teräskappaleiden lämpötila- ja faasimuutoskäyttäytymistä sekä estimoidaan mallin reunaehtoja. Näin luotu inversio-ongelma on kuitenkin matemaattisesti tarkasteltuna ns. huonosti asetettu ongelma, ja sen ratkaisemiseksi käytetään iteratiiviseen säännöllistämiseen perustuvaa menetelmää. Väitöstyön inversioanalyysiä havainnollistetaan pilot-mittakaavan kokeiden avulla, joissa hilsepesuria käyttäen koekappaleen jäähtymisnopeus saadaan erittäin korkeaksi. Tulokset nostavat esille inversio-analyysiin liittyviä ongelmia ja rajoitteita nopeaan jäähtymiseen sekä lämpötilamittauksiin liittyen
Al, Malki Uthman Mosfer. "The novel quenching and partitioning heat treatment of steel." Thesis, University of Leeds, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595670.
Повний текст джерелаBigg, Timothy David. "Quenching and partitioning : a new steel heat treatment concept." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/3145/.
Повний текст джерелаSulaiman, Samsiah. "Structure of properties of the heat affected zone of P91 creep resistant steel." Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20080916.150054/index.html.
Повний текст джерелаParay, Florence. "Heat treatment and mechanical properties of aluminum-silicon modified alloys." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41146.
Повний текст джерелаMicrostructural assessment was done by quantitative metallography using image analysis coupled to SEM while mechanical testing comprised tensile testing, hardness and microhardness measurements as well as impact tests.
The greatest improvement in mechanical properties obtained with modification was observed for the lower rates of solidification, i.e sand casting. The effect of modification on the heat treatment response of 356 alloy was investigated. The differences between unmodified and modified microstructures were more important in sand cast samples than in permanent mold cast samples. After one hour of solution heat treatment at 540$ sp circ$C, both permanent mold unmodified and modified microstructures became similar in terms of silicon particle size and sphericity. The processes which led to this were different. Silicon platelets in the unmodified structures segmented while silicon particles in the modified alloy coarsened. The final result was however the same. In sand cast alloy, the initial microstructural differences persisted after up to 12 hours of solution treatment. The coarser the initial as-cast microstructure, the greater the improvements associated with modification and heat treatment.
It was also found that porosity caused by modification can negate many of the microstructural benefits by decreasing tensile strength and percent elongation. It was demonstrated that modification also has an influence on the aluminum matrix. The hardness of modified alloy was found to be less after the T6 temper than in unmodified alloy. This was reflected in a lower yield strength of modified 356 alloy.
Quantitative microstructure-mechanical property relationships were established for the permanent mold samples. The best silicon-structure characteristics to predict the tensile properties were found to be the particle count per unit area and the particle area.
It was also determined that hardness can be a simple and inexpensive means whereby ultimate tensile strength and yield strength of 356 alloy in the T4 condition or T6 condition can be estimated.
Wu, Chang Kai. "Predicting the Response of Aluminum Casting Alloys to Heat Treatment." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-dissertations/117.
Повний текст джерелаJeong, Tae Ki 1968. "Subcritical heat treatment of cold rolled multi-phase trip steel." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82605.
Повний текст джерелаTenner, Jonathan. "Optimisation of the heat treatment of steel using neural networks." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.719165.
Повний текст джерелаCarsbring, Amanda. "Heat Treatment and Secondary Phase Formation in FeCrNi Medium Entropy Alloys." Thesis, KTH, Materialvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291251.
Повний текст джерелаHögentropilegeringar och mediumentropilegeringar har studerats närmre de senaste åren på grund av deras intressanta mekaniska egenskaper. En högentropilegering består vanligtvis av fem eller flera baselement, och en mediumentropilegering har tre eller fyra baselement. Detta skiljer dem från konventionella legeringar som i regel har ett, maximalt två, baselement. Dessa typer av multi-baslegeringar har ansetts ha intressanta egenskaper på grund av deras höga konfigurationsentropi, vilken tros vara orsaken till stabilisering av fast lösningsfas i legeringarna. Högentropieffekten som bidrar till stabil enfas i dessa legeringar har diskuterats och har emellertid inte visat sig vara tillförlitligt för att förutsäga vilka multi-baslegeringar som blir fast lösningsfas vid ett lägre temperaturintervall. Ändå har några av de undersökta legeringarna intressanta egenskaper som hög duktilitet och goda termiska egenskaper, vilket är fallet för högentropilegeringen CoCrFeMnNi och mediumentropilegeringen CoCrNi som båda är enkel FCC-fas vid lägre temperaturer. Detta examensarbete syftar till att undersöka en av de mindre omnämnda mediumentropilegeringarna: ekvimolär FeCrNi. Denna legering har studerats tidigare, och det visade sig att det kan finnas en möjlighet att utskiljningshärda legeringen. För att ytterligare studera detta legeringssystem producerades tre FeCrNi-legeringar i ett sammansättningsintervall nära ekvimolär sammansättning, som sedan genomgick en serie åldringsbehandlingar för att studera mängden utskild sekundär fas beroende på sammansättning och åldringstemperatur. Målet är att utvärdera och tolka data som finns i de olika CALPHAD-databaserna som används i beräkningsverktygen Thermo-Calc och FactSage, och därefter göra jämförelser med experimentresultaten. Detta för att diskutera möjligheterna att härda dessa legeringar med partikelutskiljning. De legeringar som valts och tillverkats är 33Fe33Cr33Ni, 40Fe30Cr30Ni och 45Fe30Cr25Ni, alla angivna i molprocent. Genom experimentella undersökningar med röntgendiffraktionsanalys hittades att BCC-fas med höga halter Cr bildats i alla legeringar efter majoriteten av åldringsbehandlingarna som utförts. Volymfraktionen av BCC kvantifierades genom beräkningar från referensintensitetsförhållande (RIR). Från kvantifiering fås den största volymfraktionen BCC i den ekvimolära 33Fe33Cr33Ni-legeringen, och den lägsta fraktionen BCC i 40Fe30Cr30Ni-legeringen. Högre volymfraktion BCC sammanfaller med en förhöjd hårdhet i alla tre legeringarna. Det visar sig också att utav de tre jämviktsfasberäkningarna som används i detta projekt så är det ThermoCalc-ståldatabasen TCFE10 som gett resultat som överensstämmer med experimentresultaten. För framtida undersökningar inom detta område rekommenderas att studera de mekaniska egenskaperna hos FeCrNi och bedöma möjligheterna för tillämpning av materialet.
Kish, Joseph J. "Active-passive corrosion of Fe-Cr-Ni alloys in hot concentrated sulphuric acid solutions /." *McMaster only, 1999.
Знайти повний текст джерелаOhlsson, Jonas. "Effects of different heat treatments on hardness of Grade 91 steel." Thesis, Karlstads universitet, Avdelningen för maskin- och materialteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-32805.
Повний текст джерелаIyer, Kaushik A. "Quantitative characterization of thermophysical properties in computational heat transfer." Full text open access at:, 1993. http://content.ohsu.edu/u?/etd,273.
Повний текст джерелаHodgson, David K. "The Post Weld Heat Treatment Response in the Heat Affected Zone of 2.25Cr-1Mo Steel." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1367416587.
Повний текст джерелаWarke, Virendra S. "Predicting the response of powder metallurgy steel components to heat treatment." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-072808-100705/.
Повний текст джерелаShi, Shu. "Repair weldability of heat-resistant stainless steel casings-HP45NB, HP50NB and 20-32NB alloys." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1140490923.
Повний текст джерелаCupido, Llewellyn Heinrich. "Experimental and numerical investigation of heat treatment of al-si-cu alloy." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/1291.
Повний текст джерелаAluminium alloys has seen recent increase usage in the automotive industry. This is due to the global obligation towards carbon emission reduction and fuel efficiency in the transport sector. The good strength-to-weight ratio offered by Al-Si-Cu alloys showed promising results towards the compliance of these environmentally friendly criteria. The enhanced mechanical properties is obtained when the alloy is subjected to the T6 heat treatment process, which cause microstructural changes due to the evolution of intermetallic phases. The process involves solution heat treatment, for dissolving soluble Cu- and Mg-containing phases, the homogenization of alloying elements, and the spheroidisation of eutectic Silicon. It is followed by quenching, for maximum precipitation hardening particle retention in solution, and a further artificial ageing process with the aim to acquire a uniform distribution of small precipitates, for strength improvement. The heat treatment schedule applied in this study was conducted as follows: Solution heat treatment at a temperature of 525°C for 6h Quenching in water of temperature 50°C; Artificial ageing for 8h at a temperature of 175°C, and then after left inside furnace to cool down to room temperature. This is higher than the 520°C, but shorter than the 8-12h, observed in literature. Also, quenching is done at a lower temperature rather than 60°C, and artificial ageing at a higher temperature, rather than the 155°C. This was done to be able to draw a comparison between the MAGMASOFT® simulation, which has this non-adjustable schedule, and the experimental results. The simulated and experimental results were comparable and similar outcomes, but with some discrepancies. Such as the porosity was far more visible and intense in the experimental, than what was predicted by the software. The as-cast and heat treated microstructure revealed the expected evolution of intermetallic particles, such as dissolving of the Al2Cu and the spheroidisation of the eutectic Si phases. Another phase that was identified was the insoluble AlFeSi and other possible Fe-containing phases, which due to the higher solution heat treatment temperature, showed partial fragmentation and dissolution. The study provided practical data about the effect of heat treatment on microstructural evolution and how it affects the properties of the Al-Si-Cu alloy. It also brought to the attention and understanding of how critical pouring temperature is, as it affect the initial nucleation, and cooling rate, and therefore the micro and macro properties.
Li, Cheng. "Effect of heat treatment on the microstructure of a 2CrMoNiWV rotor steel." Thesis, Sheffield Hallam University, 1996. http://shura.shu.ac.uk/3133/.
Повний текст джерелаYan, Pei. "High frequency induction welding & post-welding heat treatment of steel pipes." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609702.
Повний текст джерелаXie, Yun. "Development of Al-Mg-Si aluminium alloys for automobile applications." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366371.
Повний текст джерелаVu, Si Man. "Effect of heat treatment, oxidation and passivation on corrosion behavior of titanium alloy in simulated body fluid." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2493961.
Повний текст джерелаHinton, Kimberly D. "Extended heat treatment effects on the fracture toughness of cast aluminum alloy A357." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/17361.
Повний текст джерелаSterjovski, Zoran. "Investigation of postweld heat treatment of quenched and tempered pressure vessel steels." Access electronically, 2003. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20031127.160623/index.html.
Повний текст джерелаShepardson, Kevin W. "Diffusion and Phase Change During Heat Treatment of Ni-B Coatings on Steel." Digital WPI, 2008. https://digitalcommons.wpi.edu/etd-theses/416.
Повний текст джерелаTan, Vincent Tandean. "Heat treatment optimization in the manufacture of Wilson Rockwell steel hardness test blocks." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55236.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 84-85).
The heat-treatment process in the manufacture of Wilson Rockwell steel hardness test blocks often produces parts which are inconsistent in the mean hardness and hardness uniformity. In this thesis, the sources of variation in the mean hardness and hardness uniformity of the test blocks are identified by means of metallurgical study and Design of Experiments methodology. The uniformity of temperature distribution within the heating chamber and the effect of temperature and material composition on the final microstructure of the steel are analyzed. The hardness measurements and preparation of metallographic specimens follow the standards defined by the American Society for Testing and Materials (ASTM). Several control factors including soak temperature, soak time and location within the heating furnace are included in the Design of Experiment. The effects and interactions of control factors are studied using analysis of variance (ANOVA) techniques. Response Surface Methodology (RSM) was used to minimize the hardness variation on the interaction of the control factors. The heat-treatment experiment indicated that non-uniform temperature distribution within the heating chamber resulted in test blocks of different mean hardness in a batch run. The experiment also demonstrated that hardening temperatures below the homogeneous austenite formation temperature resulted in a large hardness variation. Several control factors and interaction between the factors that are significant on the mean hardness and hardness variation are identified. And finally, recommendations of control factor settings that minimize the hardness variation are presented in this thesis.
by Vincent Tandean Tan.
M.Eng.
Okhrimenko, V. O., Оксана Петрівна Гапонова, Оксана Петровна Гапонова, and Oksana Petrivna Haponova. "Effect of heat treatment on structure and properties of austenite-martensite stainless steel." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/46865.
Повний текст джерелаAussaguel, Pierre. "A simplified finite element simulation for hard turning 52100 steel." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19609.
Повний текст джерелаBurrow, Andrew Charles. "A model of the argon oxygen decarburization process for refining stainless steel and alloys." Thesis, 2015. http://hdl.handle.net/10539/16476.
Повний текст джерелаMukuku, Kelvin. "Thermodynamic and parametric modeling in the refining of high carbon ferrochromium alloys using manually operated AODs." Thesis, 2017. https://hdl.handle.net/10539/24239.
Повний текст джерелаThis study and the work done involves investigating the effects of different parameters on the decarburization process of high carbon ferrochromium melts to produce medium carbon ferrochrome, and takes into account the manipulation of the different parameters and thermodynamic models based on actual plant data. Process plant data was collected from a typical plant producing medium carbon ferrochrome alloys using AODs. The molten alloy was tapped from the EAF and charged into the AOD for decarburization using oxygen and nitrogen gas mixtures. The gases were blown into the converter through the bottom tuyeres. Metal and slag samples and temperature measurements were taken throughout the duration of each heat. The decarburization process was split into two main intervals namely first stage blow (where carbon content in the metal bath is between 2-8 wt. % C) and second stage blow (carbon mass% below 2 wt. %). The first and second blow stages were differentiated by the gas flow rates whereby the first stage was signified by gas flow ratio of 2:1 (O2:N2), whilst the stage blow had 1:1 ratio of oxygen and nitrogen respectively. The effect of Cr mass% on carbon activity and how it relates to rate of decarburization was investigated, and the results indicated that an increase in Cr 66.54 – 70.5 wt. % reduced carbon activity in the metal bath from 0.336 – 0.511 for the first blowing stage. For the second blowing stage, the increase in Cr mass % of 67.22 – 71.65 wt. % resulted in an increase in C activity from 0.336 – 0.57. The trend showed that an increase in chromium composition resulted in a decrease in carbon activity and the same increase in Cr mass% resulted in reduced carbon solubility. Based on the plant data, it was observed that the rate of decarburization was time dependent, that is, the longer the decarburization time interval, the better the carbon removal from the metal bath. An interesting observation was that the change in carbon mass percent from the initial composition to the final (Δ%C) decreased from 10.18 – 8.37 wt. % with the increase in Cr/C ratio from 8.37 – 10.18. This effect was attributed to the chromium affinity for carbon and the fact that an increase in chromium content in the bath was seen to reduce activity of carbon. It was also observed that the effect of the Cr/C ratio was more significant in the first stage of the blowing process compared to the second blowing stage. A mass and energy balance model was constructed for the process under study to predict composition of the metal bath at any time interval under specified plant conditions and parameters. The model was used to predict the outcome of the process by manipulating certain parameters to achieve a set target. By keeping the gas flow rates, blowing times, gas ratios and initial metal bath temperature unchanged, the effect of initial temperature on decarburization in the converter was investigated. The results showed that the carbon end point with these parameters fixed decreased with increasing initial temperature, and this was supported by literature. The partial pressure of oxygen was observed to increase with decrease in C mass % between the first and second blow stages. For the second stage blow the partial pressure changed from 5.52*10-12 – 2.1*10-10 and carbon mass % increased from 0.754 – 2.99 wt. %. A carbon mass % of 7.87 had an oxygen partial pressure of 4.51*10-13 whilst a lower carbon content of 1.53 wt. % had an oxygen partial pressure of 8.06*10-11. The CO partial pressure however increased with increase in carbon composition in the metal bath. When the oxygen flow rate increased, a corresponding increase in the carbon removed (Δ%C) was observed. For the first stage of the blowing process, an increase in oxygen flow rate from 388.67 – 666.5Nm3 resulted in an increase in carbon removed from 5.06 – 7.28 wt. %. The second blowing stage had lower oxygen flow rates because of the carbon levels remaining in the metal bath were around +/- 2 wt. %. In this stage oxygen flow rates increased from 125 – 286.67 Nm3 and carbon removed (Δ%C) from 0.16 – 2.093 wt. %. The slag showed that an increase in basicity resulted in an increase in Cr2O3 in the slag. As the basicity increased from 0.478 – 1.281, this resulted in an increase in Cr2O3 increase from 0.26 – 0.68. Nitrogen solubility in the metal bath was investigated and it was observed that it increased with increasing Cr mass %. The increase in nitrogen solubility with increasing Cr mass % was independent of the nitrogen partial pressures.
MT2018
Cho, Liang-Yih, and 卓良憶. "Effect of Austempering Heat Treatment on Erosion Wear of Ductile Iron and 4340 Alloy Steel." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/96914492119948318741.
Повний текст джерела大同大學
材料工程研究所
89
This research applied austempering heat treatment to obtain various microstructures in the matrix of ductile iron and AISI 4340 steel and studied their erosion wear behavior. The effects of different impact angle and microstructure on erosion wear rate and morphology were investigated. Mechanical property evaluation together with SEM analysis were also carried out to correlate the wear behavior observed.The results showed that after austempering hardness increased substantially. Impact toughness of ductile iron increased but AISI 4340 steel decreased. After erosion tests, it was determined that the wear rate of both materials were similar. However, at low angle (15 ) and high angle (90 ) impact angle, heat treated 4340 steel seemed to possessed better wear resistance than ductile iron. SEM observation revealed that cavities formed at where the spheroidal graphites located. Due to poor impact wear resistance of the graphite, they fell off from the matrix in early stage of the shot blasting leaving a hole behind that acclerated the peeling off effect of the ductile iron. Higher hardness enhanced eorsion wear resistance from the ability of sustaining deformation and peeling off effects.
RAMLI and 洛建偉. "Effects of Heat treatment on the Microstructure and Mechanical Properties of SACM 645 Alloy Steel." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/zwhyba.
Повний текст джерела南臺科技大學
機械工程系
105
The purpose of this research is to observe and study the influence of hardening and tempering processes on microstructures and mechanical properties of SACM 645 steel by using several characterization techniques which include optical microscopy, hardness testing, tensile testing, fatigue testing, X-ray diffraction and scanning electron microscopy. In the present study, effects of the nitriding treatments on the material properties of the steel were also investigated. The heat treatment condition conducted in this research consists of hardening at 925 ˚C and then tempering at 540˚C, 560˚C, 580˚C as well as nitriding treatment at 530˚C. The experimental results related to the influences on microstructure and mechanical properties of SACM 645 steel induced the following conclusions. When the SACM 645 steel was first hardened at 925˚C treated and then tempered at 580˚C, the elongation of the SACM 645 steel will increase further from 6% to 20% and the number of cycles of failure will increase from 12509 cycles to 63314 cycles with the stress of fatigue limit 693.4 MPa or 120 Kg weights, this result indicating that after tempering at 580˚C the fatigue behavior of the SACM 645 steel rose five times in exceeding the without tempering specimen in this study. These results seem to be related to the formation of tiny and homogeneous structures on the tempering at 580˚C specimens. After nitriding treatments at 530˚C for 40 hours, the fatigue limit of SACM 645 steel greatly increased to 1351587 cycles. Moreover after nitriding treatments the microhardness of SACM 645 also significantly rose to ± 1100 HV0.1. Keywords: Tempering, Nitriding, Microstructure, elongation, Fatigue.
Yu, Chun-hsin, and 尤俊鑫. "The Effect of Heat Treatment on Mechanical Properties of Low Alloy Ni-Cr-Mo Forging Steel." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/27632048877024699246.
Повний текст джерела國立高雄應用科技大學
機械與精密工程研究所
101
This study was conducted using quenching and tempering temperature heat treatment conditions change, to explore the relationship between the mechanical properties of low-alloy nickel-chromium-molybdenum forged steel with the help of microstructure. Experimental results show that low-nickel-chromium-molybdenum alloy for- ged steel hardened and then subjected to different tempering temperature te- mpering organization, will lead to massive as the tempering temperature ferrite (Blocky ferrite) grains become larger, while the acicular ferrite (Acicular ferri- te) then becomes relatively small. after hardening - heat treatment after the ten- sile strength, yield strength and hardness values are tempering temperature inc- reases with decreasing; impact toughness will follow the tempering temperat- ure increases. Quenching - heat treatment after tensile and impact fracture surface of the dimple ductile failure mode, as the tempering temperature will become more apparent. the low-temperature tempering conditions of its ductile fracture surface in addition to outside, there will be splitting failure mode char- acterized by brittle fracture occurs locally.
LIN, YUEH-FENG, and 林岳鋒. "The Heat Treatment condition effect on the Mechanical Properties and Micro Structure of alloy SNCM Steel." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4669k8.
Повний текст джерела國立高雄科技大學
機械工程系
107
Today's applications for metal materials are expanding. The requirements for wear resistance, fatigue resistance, high strength, and corrosion resistance of materials are becoming increasingly stringent. After various processing conditions, common components such as engine linkages, engine shafts, gears or chains play the most effective role. It can add elements of different compositions to improve the ductility, toughness, and rigidity of the material to extend the development of missiles, bullets, and fighter parts of the defense technology industry. Because of the different usage, different loading, and different environmental needs, materials with various characteristics of heat treatment, such as temperature quenching, tempering, cooling, are required to meet various conditions of use.Thus, the effect of heat treatment on metals is a very important research field. This research mainly studies the influence of heat treatment on the mechanical properties of SNCM materials, and the changes of grain-boundary, grain size, precipitate, etc. of the specimens after metallographic observation test to further understand the properties of the material. The experimental results show that the material with heat treatment has more than twice the stress-strain than the material without heat treatment. It can be seen through (OM) that the material that has been heat treated has a distinct ferritic carbon-iron phase, while the material that has not been heat-treated has more carbon precipitates at the grain boundary.