Дисертації з теми "Martensitic stainless steel Metallography"
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Morgan, Terence S. "Microstructural effects of neutron irradiation on ferritic/martensitic stainless steels." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/13768.
Повний текст джерелаNaraghi, Reza. "Martensitic Transformation in Austenitic Stainless Steels." Thesis, KTH, Metallografi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-37214.
Повний текст джерелаDanks, J. "Cyclic creep of T316 stainless steel." Thesis, Coventry University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328644.
Повний текст джерелаBuckley, J. R. "Hydrogen embrittlement of austenitic stainless steel." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315550.
Повний текст джерелаButler, J. J. F. "Hydrogen embrittlement of austenitic stainless steel." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374127.
Повний текст джерелаO'Donnell, I. J. "Ductile fracture in type 316 stainless steel." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356270.
Повний текст джерелаMattin, Sarah Patricia. "Nucleation of corrosion pits on stainless steel." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321495.
Повний текст джерелаPirouznia, Pouyan. "High cycle fatigue properties of stainless martensitic chromium steel springs." Thesis, KTH, Materialteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103201.
Повний текст джерелаHedström, Peter. "Deformation induced martensitic transformation of metastable stainless steel AISI 301 /." Luleå : Luleå University of Technology, 2005. http://epubl.luth.se/1402-1757/2005/79.
Повний текст джерелаHedström, Peter. "Deformation induced martensitic transformation of metastable stainless steel AISI 301." Licentiate thesis, Luleå, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25748.
Повний текст джерелаGodkänd; 2005; 20061213 (haneit)
Barlow, Lilian D. "The effect of austenitising and tempering parameters on the microstructure and hardness of martensitic stainless steel AISI 420." Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-11262009-182934/.
Повний текст джерелаGardner, L. "A new approach to structural stainless steel design." Thesis, Imperial College London, 2002. http://hdl.handle.net/10044/1/8862.
Повний текст джерелаBenítez, Vélez Soraya. "Oxidation kinetics and mechanisms in HT-9 ferritic/martensitic stainless steel." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012151.
Повний текст джерелаHirsch, Michael Robert. "Fretting behavior of AISI 301 stainless steel sheet in full hard condition." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24759.
Повний текст джерелаHaddad, Naseem Issa Abdallah. "The development of microstructure in duplex stainless steel welds." Thesis, University of Cambridge, 1990. https://www.repository.cam.ac.uk/handle/1810/221890.
Повний текст джерелаSillo, C. E. "Microstructural and chemical studies of stainless steel/refractory interactions." Thesis, University of Sheffield, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291003.
Повний текст джерелаRen, Gang. "Corrosion and passivity of 13Cr supermartensitic stainless steel." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609807.
Повний текст джерелаZangiabadi, Amirali. "Low-temperature interstitial hardening of 15-5 precipitation hardening martensitic stainless steel." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1480769348244855.
Повний текст джерелаLaws, Mark S. "Segregation at grain boundaries in sensitised A.I.S.I. 316 stainless steel." Thesis, University of Surrey, 1990. http://epubs.surrey.ac.uk/799994/.
Повний текст джерелаShenton, Paul Aidan. "Grain growth during the thermomechanical processing of austenitic stainless steel." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364249.
Повний текст джерелаTibblin, Fritjof. "Characterization of a newly developed martensitic stainless steel powder for Laser and PTA cladding." Thesis, KTH, Materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-163788.
Повний текст джерелаDeMania, Deborah Ann. "The influence of martensitic transformation on the formability of 304L stainless steel sheet." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11488.
Повний текст джерелаAlnajjar, Michella. "Corrosion properties of 17-4 PH martensitic stainless steel obtained by additive manufacturing." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEM035.
Повний текст джерелаThis PhD thesis focuses on the corrosion properties of 17-4 PH precipitation hardenable stainless steel obtained by additive manufacturing, specifically by Selective Laser Melting (SLM).It was shown that the microstructure of 17-4 PH steel fabricated by SLM was ferritic, in contrast to the typical martensitic microstructure of wrought 17-4 PH steel. This was correlated to the high cooling and heating rates (105-106 K/s) experienced during SLM that suppressed the δ ferrite to austenite transformation and retained the δ ferrite until the end of fabrication.A comparative electrochemical study was conducted on both steels. It was found that the SLM-ed steel had superior general corrosion resistance than the wrought steel. This was attributed to the absence of MnS inclusions in the SLM-ed steel. In contrast, in the wrought material, the dissolution of the MnS inclusions resulted in the redeposition of sulphur-rich species all over the surface, which contributed to the destabilization of the passive film.A hydrogen embrittlement study was also conducted. It was found that the SLM-ed ferritic steel was more susceptible to hydrogen embrittlement than the wrought martensitic steel. The difference in microstructure, specifically the grain size, played a major role in this difference in behavior. In the SLM-ed ferritic steel subcritical cracking was transgranular and its initation was governed by the stress level and the amount of hydrogen introduced into the material. On the other hand, in the wrought martensitic steel, subcritical cracking was along the prior austenitic grain boundaries and it was shown that its initiation required at least a small amount of plastic deformation
McCann, Scott. "A study of environmental exposure on structural adhesively bonded austenitic stainless steel." Thesis, Sheffield Hallam University, 2003. http://shura.shu.ac.uk/20033/.
Повний текст джерелаvan, Niekerk Cornelis Janse. "In-situ alloying of AISI 410L martensitic stainless steel with nitrogen during laser cladding." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/61341.
Повний текст джерелаDissertation (MEng)--University of Pretoria, 2016.
Materials Science and Metallurgical Engineering
MEng
Unrestricted
Benchouieb, Rachid. "Effect of multi-pass hot rolling on recrystallisation behaviour of ferritic stainless steel." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389668.
Повний текст джерелаIonescu-Gabor, Sorin. "Study and empirical modelling of recrystallisation annealing of martensitic chromium steel strip by means of EBSD." Licentiate thesis, KTH, Materials Science and Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10539.
Повний текст джерелаRecrystallisation annealing, a repeated heat treatment between different stages of cold rolling of martensitic chromium steel strip, is successful when neither high rolling forces nor wear of the working rolls occur during the subsequent cold rolling. Mechanical properties as tensile strength, yield, elongation or hardness have been, by tradition, the criteria that described the quality of the annealing process. In recent years, the development of the measurement equipment in the rolling mills and of the instruments for material investigations has accentuated more and more the role played by the microstructural properties in the evaluation of the heat treatment. Two microstructural characteristics of the degree of annealing are, firstly and most important, the recrystallisation degree, and, secondly, the secondary carbide density.
The sample manufacturing and heat treatment, modelling and microstructure investigations by light optical- (LOM) and scanning electron microscopy (SEM) described in this article were carried out at Sandvik Materials Technology’s R&D Department and Bell Furnace Line in Sandviken, Sweden, while microstructure investigations and evaluation by scanning electron microscopy with field emission gun (FEG-SEM) and electron back scatter diffraction (EBSD) were done at the Corrosion and Metals Research Institute (KIMAB) in Stockholm, Sweden.
The first part of this work shows that, in contrast to the traditional methods LOM and SEM, that use chemical etching for the preparation of the samples, EBSD can successfully characterise recrystallised structures in annealed martensitic chromium steels. Unlike conventional microscopy with LOM and SEM, EBSD is able to reveal the grain geometry, as well as to separate and identify the different phases in this kind of steels (ferrite, M23-, M6-carbides). Important parameters such as grain size, particle size and recrystallised fraction can be measured with high accuracy. This information can be used to understand, evaluate, control and even predict the recrystallisation annealing of martensitic chromium steel.
The second part of this work presents how the results from microstructure description by EBSD can be directly used in relatively simple empirical models for determination of recrystallisation degree as function of the annealing parameters and the deformation history. EBSD was applied to evaluate the degree of recrystallisation in a series of annealing tests, with the purpose to model recrystallisation temperature in two types of martensitic chromium steel strip, a traditional one and one alloyed with molybdenum, cold rolled with different amounts of reduction and annealed with different temperatures, soaking times and heating rates. The empirical quadratic models were built with Umetrics’ software for experimental design, MODDEÒ 8.0 and they defined the recrystallisation degree (limits for LAGB and HAGB were set to 1.5° and 7.5° for the first grade and 2.5° and 10° for second one) and the secondary carbides density as functions of annealing temperature, soaking time and cold reduction (the factor heating rate was removed as nonsignificant). To be observed that these empirical models were fit much better for the recrystallisation degree than for the secondary carbides density.
The modelling work described above, together with the implementation of online physical temperature models in the bell annealers may lead to an increased productivity in the production plant by shortening the annealing cycle and minimising scrap and thus to an economical gain of ca 1,5 MSEK per year at Sandvik Materials Technology.
Prasannavenkatesan, Rajesh. "Microstructure-sensitive fatigue modeling of heat treated and shot peened martensitic gear steels." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31713.
Повний текст джерелаCommittee Chair: David L. McDowell; Committee Member: G. B. Olson; Committee Member: K. A. Gall; Committee Member: Min Zhou; Committee Member: R. W. Neu. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Angella, Giuliano. "Strain path, flow stress and microstructure evolution of an austenitic stainless steel at high temperature." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251254.
Повний текст джерелаLee, Chihoon. "Phase Transformations Accompanying Low-Temperature Carburization of Martensitic Stainless Steels under Paraequilibrium Conditions." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1325878014.
Повний текст джерелаJayaraman, Vikram. "Production, characterization and testing of Tempered Martensite Assisted Steels (TMAS) obtained via subcritical annealing of cold rolled TRIP steels." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99769.
Повний текст джерелаIn current TRIP grades, the retained austenite particles present have to posses certain characteristics such as, optimum carbon concentration, optimum grain size and morphology etc. in order to account toward mechanical properties. Such limiting characteristics in turn minimize the processing window and make TRIP processing expensive and difficult to control. In this work, it is suggested that Tempered Martensite Assisted Steels (TMAS) obtained from TRIP steels via subcritical annealing of cold rolled TRIP steels may potentially replace TRIP steels. Relationship between the retained austenite volume fractions and mechanical properties was developed for TRIP steels. The effect of variation of retained austenite on tempered martensite volume fraction in TMAS, which in turn affect the mechanical properties was also investigated in depth. Results indicate that tempered martensite particles in TMAS do not have any limiting factors as in the case of RA in TRIP steels, in order to contribute toward enhancement of mechanical properties. Results also indicate that TMAS offers better strength levels compared to TRIP steels for same the level of formability.
Retained austenite volume fractions in TRIP steels were measured through XRD. Cold rolling of the samples was done in a laboratory scale rolling machine. The microstructures were analysed using conventional and color etching techniques. A new color etching technique for viewing all the four major phases in TRIP steel was developed in this work. The mechanical properties of both TRIP and TMAS were assessed by shear punch testing. And finally, the relationship between tempered martensite volume fraction and TMAS properties was developed and was compared to TRIP properties.
Powell, D. J. "A study of the precipitation, creep and creep-fatigue characteristics of a 20/25/Nb-stabilised stainless steel." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370959.
Повний текст джерелаRimko, Marcel. "Struktura a vlastnosti martenzitických korozivzdorných ocelí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417077.
Повний текст джерелаMartin, Diaz Ulises. "STRESS CORROSION CRACKING OF AUSTENITIC STAINLESS STEEL REBAR IN SIMULATED CONCRETE PORE SOLUTION INFLUENCED BY STRAIN-INDUCED MARTENSITIC TRANSFORMATION." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1626520184452948.
Повний текст джерелаChen, Meichuan. "Synchrotron Radiation X-ray Diffraction Study on Microstructural and Crystallographic Characteristics of Deformation-Induced Martensitic Transformation in SUS304 Austenitic Stainless Steel." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215535.
Повний текст джерелаLiu, Jikai. "Influence of metallurgical phase transformation on crack propagation of 15-5PH stainless steel and 16MND5 low carbon steel." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00833206.
Повний текст джерелаKusunoki, Takuya. "Quantification of the Tempering Response in Type 410 Steel Welds." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1607011624665895.
Повний текст джерелаLin, Sen. "Deformation-Induced Martensitic Transformation and Mechanical Properties of Duplex and Austenitic Stainless Steels : A Synchrotron X-Ray Diffraction Study." Thesis, KTH, Metallografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233334.
Повний текст джерелаPatra, Anirban. "Modeling the mechanical behavior and deformed microstructure of irradiated BCC materials using continuum crystal plasticity." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50366.
Повний текст джерелаRosa, Guilherme Cortelini da. "Estudo da usinabilidade no torneamento a seco do aço inoxidável martensítico AISI 420 C endurecido com ferramenta de metal-duro." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/165625.
Повний текст джерелаThe study of the material’s machinability is very important for the determination of important machining properties. This logic applies to hardened martensitic stainless steel AISI 420 C used in the manufacture of high precision parts, surgical instruments, shafts, turbines and cutlery. In this way, investigations were carried out using hardened workpieces (quenching and tempering) with hardness of (48 1) and (53 2 HRC) in dry turning using ISO-S grade carbide tools with extra-fine grains and PVD coating. For these workpieces, the cutting speed and the feed rate were varied and the machining forces and the residual stresses generated in the part were evaluated. For the material with 53 HRC, the tool-life and the surface roughness were also analyzed. In the analysis of the results obtained for the material with 48 HRC, residual stresses become less compressive (circumferential direction) and more tensile (axial direction) with increasing feed-rate. Moreover, smaller values of residual stress were generated using lower feed-rate at higher cutting speed. In the tests for the material at 53 HRC, the tool-life was between 100 and 350 min for the conditions tested. Flank and notch wear were evidenced in all situations. The flank face of the tool also showed adhesion of the workpiece material under all cutting conditions. When analyzing the inserts at their end of life, it was verified that the main mechanisms of tool wear were abrasion and attrition. In addition, under the most severe cutting conditions, the flank face of the tool exhibited mechanical cracks and the subsurface layer of the workpieces presented microstructural modifications. The registered profiles and roughness parameters were affected by wear during the tool-life. With respect to the circumferential residual stresses generated with the fresh tool, these were mostly compressive stresses. With the progression of tool flank wear, there was an increase in the values of the residual stress (from compressive to less compressive or even tractive). For the axial residual stresses, the values showed a tendency to remain compressive. It was observed for the residual stress profiles analyzed that the residual stresses were compressive and depended on the depth of subsurface layer. Therefore, within the cutting conditions considered, it can be concluded that hardened martensitic stainless steel AISI 420 C parts can be manufactured by finishing turning with carbide tools, allowing long tool-life, low surface roughness values, as well as compressive residual stress values, which are important machinability information for this material.
Sierra, Robinson. "Investigation of the mechanical behaviour of TRIP steels using FEM." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99793.
Повний текст джерелаEl, Hilali Fatima. "Etude de la sensibilité à la dépassivation des aciers inoxydables martensitiques à durcissement par précipitation : conséquence sur la corrosion sous frottement et la corrosion sous contraintes." Châtenay-Malabry, Ecole centrale de Paris, 1987. http://www.theses.fr/1987ECAP0055.
Повний текст джерелаAmbrož, Ondřej. "Vliv podmínek tuhnutí na strukturu a vlastnosti austenitických chromniklových ocelí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319276.
Повний текст джерелаNovotný, Jan. "Svařování martenzitické korozivzdorné oceli pomocí hybridní technologie Laser - TIG." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417122.
Повний текст джерелаBueno, Juliana Cristina. "Desenvolvimento da técnica de identificação de fases por metalografia óptica com nanoindentação em liga inoxidável com efeito de memória de forma." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263102.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Neste trabalho foi estudada uma liga inoxidável Fe-Mn-Si-Cr-Ni-Co com efeito de memória de forma (EMF) e os objetivos principais foram otimizar a técnica de coloração por ataque químico (color etching) para identificação e análise das fases presentes na microestrutura, o que permitiu a determinação da dureza da martensita-? e da austenita-? através da técnica de nanoindentação. O desenvolvimento deste processo também permitiu a quantificação das fases e e g por microscopia óptica. A técnica de coloração por ataque químico consiste na utilização de reagentes específicos que resultam em uma microestrutura composta por várias colorações, o que permite identificar fases por microscopia óptica. Os resultados de dureza obtidos por nanoindentação foram de 7,0 GPa para a martensita-? e de 3,0 GPa para a austenita-?. Já para a fração volumétrica da martensita-?, os resultados obtidos por microscopia óptica variaram de 33 a 40 % para amostras no estado deformado. Para amostras de tamanho de grão 123 ?m e 3º ciclo de treinamento, os resultados foram coerentes com os obtidos por difração de raios X de trabalhos anteriores para a mesma liga
Abstract: In this work a Fe-Mn-Si-Cr-Ni-Co stainless alloy with shape memory effect (SME) was studied and the main objectives were to optimize the technique of coloration by chemical attack (color etching) for identification and analysis of the phases in the microstructure, allowing the determination of the ?-martensite and the -austenite hardness by nanoindentation technique. The development of this process also allowed the quantification of the ?- and ?- phases by optical microscopy. The technique of coloration by chemical attack consists in the use of specific reagents to identify phases by color using optic microscopy. The hardness obtained was 7.0 GPa for ?-martensite and 3.0 GPa for ?-austenite. The volume fraction of the ?-martensite, measured with optical microscopy varied from 33 to 40 % for samples in the deformed state. For samples with grain size of 123 ?m and after the 3º training cycle, the results were coherent with the obtained by X ray diffraction of previous works for the same alloy
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
Saied, Mahmoud. "Experimental and numerical modeling of the dissolution of delta ferrite in the Fe-Cr-Ni system : application to the austenitic stainless steels." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI016/document.
Повний текст джерелаResidual δ-ferrite is widely encountered in the as-cast microstructure of austenitic stainless steels. It stems from the incomplete high temperature solid-state δ→γ transformation occurring upon the solidification stage. Its presence has a detrimental effect the hot workability of stainless steels, leading to the formation of edge cracks and sliver defects during slabs hot rolling. This PhD work aims at bringing more understanding of the kinetics of high temperature δ→γ transformation in austenitic stainless steels via experimental and numerical modeling. The transformation was studied in a ternary Fe-Cr-Ni ingot-cast alloy with composition close to the industrial alloys. Three ferrite morphologies were identified: lathy at the edge of the ingot, vermicular and lathy at the center. Their dissolution kinetics were established at temperatures ranging from 1140°C to 1340°C and characterized in terms of ferrite fraction and Cr and Ni diffusion. The vermicular ferrite undergoes a transient growth followed by a high then a low rate dissolution regimes. On the other hand, ferrite dissolution was also studied in the multilayered microstructures. such microstructures were elaborated by alternating ferrite and austenite sheets of the Fe-Cr-Ni system, diffusion-bonded by Hot isostatic Pressing and reduced in thickness by successive rollings. Dissolution is easier to handle in such microstructures thanks to the initial planar δ/γ interfaces. Analysis of the experimental results were carried out with a numerical moving-boundary model of diffusion-controlled δ→γ transformation. Diffusion can be treated in the planar, cylindrical and spherical geometries. As a preliminary validation, the model was used to analyze kinetics of ferrite dissolution in the multilayered microstructures. It was then applied to the cast alloy using an original descriptive approach combining spheres and cylinders as equivalent morphology of dendritic ferrite. Although based on simplifying assumptions, the model was able to reproduce experimental results with satisfactory agreement. Mechanisms underlying the initial growth of vermicular ferrite and the transition in dissolution regimes were outlined. The effect of a wide range of input parameters has been considered and relevant parameters for quantitative calculations were brought to light, such as thermodynamical descriptions of the Fe-Cr-Ni system, composition gradients and distribution of ferrite's radii
Beraldo, Camila Haga. "Efeito da temperatura de envelhecimento sobre as propriedades mecânicas e resistência à corrosão por pite do aço inoxidável martensítico endurecido por precipitação UNS S46500." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-15102014-163925/.
Повний текст джерелаThe precipitation hardened stainless steels have been widely used in the aircraft industry to combine mechanical strength, fracture toughness and corrosion resistance. And therefore, are materials that enable replacement of the carbon steels used today, which require additional surface treatment, such as cadmium plating, to improve the corrosion resistance. The use of such coatings brings disadvantages such as cost, manufacturing, susceptibility to hydrogen embrittlement beyond environmental aspects. In this context, the precipitation hardened steel UNS S46500, known as Custom 465® were evaluated for the effect of aging temperature on the mechanical properties and the resistance to pitting corrosion .Treated samples in solubilized and aged condition at 510°C (H950) and 538ºC (H1000) were subjected to tensile strength test, microstructural characterization and potentiodynamic polarization (PP) tests to determine the pitting corrosion resistance. The microstructural studies were performed with the aid of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction. Analyzes were also performed using the Thermo -Calc software. The resistance to pitting corrosion was evaluated at 0.6M NaCl solution with increasing additions of Na2SO4. The results obtained from tests of PP in both heat treatment conditions were compared with each other and with results available in the literature (CALDERÓN HERNANDEZ, 2012) to stainless steel UNS S30403 (304L). The analysis of the microstructure revealed that the steel aged Custom 465 ® presents a martensitic matrix, chi precipitates, Ni3Ti precipitates and austenite phase. The H950 age treatment had higher mechanical strength and lower elongation than the treatment H1000. Such behavior was due to the production of higher percentage of chi and a lower percentage of austenite phase in aging treatment. The different heat treatments, solubilized condition, H950 and H1000 showed almost the same pitting corrosion resistance. On the other hand, the Custom 465® showed good response to pitting inhibition with increasing nucleating additions of sulfate in 0.6M NaCl, with enhanced result for H1000 condition. Furthermore, by adding sulfate was possible to obtain greater pitting corrosion resistance of Custom 465® compared to the 304L steel. This behavior has been discussed in terms of the chemical affinity between nickel, chloride and sulphate, leading to higher pitting corrosion resistance when the steel contains a higher nickel 9 content (which is the case of steel Custom 465®). This study indicates that the criterion in selecting the aging heat treatment of Custom 465® steel must be the desired mechanical properties, since the pitting corrosion resistance was found to be substantially independent of heat treatment.
Stone, David Joseph. "Optimal Composition Window of Type 410 Welding Consumables and Base Metals for Hydro-processing Applications." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu149270477418846.
Повний текст джерелаGodin, Hélène. "Effet de la microstructure sur la transition ductile-fragile d'aciers inoxydables martensitiques emboutissables à chaud." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM036.
Повний текст джерелаHot stamping steels are widely used for lightweight automotive structural parts, because of their excellent combination of formability, strength and ductility. New hot stamping martensitic stainless steel grades have been developed for this application. Among key properties required for automotive structural parts, impact toughness is a useful indicator of crash worthiness. However, the link between microstructure and the brittle fracture resistance of these steels had still to be established. The present work examined the effect of the chemical composition (niobium addition), austenitization heat treatment, and cooling conditions after hot stamping, on the microstructure and impact toughness of these steels. In order to do this, a detailed analysis of the microstructures obtained after various heat treatments was done. The microstructures are complex, with more or less auto-tempered martensitic laths, untransformed ferrite, retained austenite, and fine alloy carbides. The ductile-to-brittle transition behavior was characterized using Charpy tests over a large temperature range. The critical cleavage fracture stress was determined to be around 2400 MPa whatever the microstructure, by applying the local approach to fracture. The main effect of niobium was torefine the grain size, resulting in a strong improvement of the ductile-to-brittle transition behavior by increasing the resistance to cleavage crack propagation. Moreover, the heat treatment impacts the retained austenite fraction and thus modifies incipient plasticity and the strain necessary to reach locally the criticalstress required to trigger cleavage fracture. In this way, retained austenite plays a determining role to decrease the ductile-to-brittle transition temperature
Rocancourt, Norman. "Etude de solutions innovantes de dépôts de superalliages et traitements de surface pour augmenter la résistance à l'usure et le comportement des moules métalliques de verrerie." Thesis, Rouen, INSA, 2016. http://www.theses.fr/2016ISAM0014.
Повний текст джерелаGlass moulds have to withstand very high temperatures which can far exceed 650 °C during the glass forming process. They are exposed to very tough conditions such as abrasive wear and physico-chemical reactions, accentuated by thermal shocks due to high speed contact with hot glass melt. The aim of this work is to find innovative solutions for superalloy coating or surface treatments in order to increase the service life of glass tools. Three innovation projects are presented in this report. The first one is dedicated to PTA (Plasma Transferred Arc) welded coating of composite Co/NiB powder on copper alloy moulds. The second one is about technical feasibility of a multilayer PVD (Physical Vapor Deposition) coating with properties congruent to glass production in term of hardness and thermal stability, on AISI 431 plunger stainless steel. Last but not least, the third innovative project is about nitriding by ion implantation with multicharged nitrogen ions on AISI 431 stainless steel. We notice after ion implantation a significant hardness increase (+ 240 %). A multi-experimental and multi-scale approach was carried out in order to study the implanted material microstructure and its evolution after annealing at 650 °C during 1h to predict the material behavior during production and correlate it to hardness properties