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Статті в журналах з теми "Microhardness of steel"
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Stepanov, Makar S., Yuri M. Dombrovskii, and Levon V. Davidyan. "Microarc surface alloying of tool steels." MATEC Web of Conferences 226 (2018): 03007. http://dx.doi.org/10.1051/matecconf/201822603007.
Повний текст джерелаАнотація:
A new method of accelerating of steel diffusion saturation during thermo-chemical treatment – microarc surface alloying is proposed. The steel product is placed in a metal container filled with coal powder, and heated by passing an electric current. Powder having microarcs, which are concentrated around the surface of the product with the formation of zones of local gas discharge. This significantly speeds up the diffusion saturation. After carburizing of steel 20Cr13 is formed a diffusion layer thickness of 13-15 μm microhardness of 10.5 to 12.5 HPa, located below the eutectoid area a thickness of 300 μm and a hardness of 6.5 GPA. After boriding of steel Cr12V1 after standard heat treatment, the surface layer with a thickness of 170-180 μm consists of a base with microhardness of 9.3-9.6 GPA with inclusions of microhardness of 14.5-15.0 GPA. After boriding of steel 5CrNiMo formed a layer thickness of 250-260 μm with a composite structure consisting of sections of the eutectoid structure of microhardness of 7.0-8.0 GPA, surrounded by boride eutectic microhardness 12.0-12.5 GPA. The composite structure provides the combination of very hard boride eutectic and eutectoid plastic mixture. After boriding of steel W6Mo5Co5 after standard heat treatment, the surface layer thickness of 230-240 μm consists of a base of microhardness 11,0-11,2 GPA with inclusions of microhardness 13,5-14,5 GPA. Given the high intensity of diffusion saturation, microarc surface alloying is recommended for surface hardening of tool steels.
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Astashchenko, V. I., G. F. Mukhametzyanova, and A. G. Shagiev. "Criteria for Evaluating the Manufacturability of Steels when Cutting with an Edge Tool." Materials Science Forum 1052 (February 3, 2022): 62–67. http://dx.doi.org/10.4028/p-rim7y5.
Повний текст джерелаАнотація:
Comprehensive metallographic studies of steel forgings with different machinability by cutting with an edge tool were also completed. Structural features and properties of steel were revealed, having adversely influence on tool life and the process of chip formation during cutting. Metal Science criteria have been given for assessing the manufacturability of steel at machining operations. Microstructures of steel with satisfactory and unsatisfactory machinability are presented. The technological parameters of heat treatment of steel 18HGR have been established, causing a show of banding of ferrite-pearlite structure. The thermokinetic diagram shows an area of development of the segregation banding structure. An important role in assessing the manufacturability of steels is shown of the microhardness of individual structural components and the difference in values between them. The best results in machinability by cutting are observed when the microhardness of pearlite is not more than 350 HV, ferrite is not more than 210 HV and the difference in microhardness between these components is not more than 80 HV.
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Benkovsky, Yu V., D. M. Kroitoru, V. I. Petrenko, P. N. Stoichev, E. V. Yurchenko, and A. I. Dikusar. "Interrelation of the Composition of Steel Treated by Electrospark Alloying and the Properties of Obtained Composite Surface." Elektronnaya Obrabotka Materialov 58, no. 1 (February 2022): 1–8. http://dx.doi.org/10.52577/eom.2022.58.1.01.
Повний текст джерелаАнотація:
Basing on the study of the elemental composition of surface composites obtained on 45, 65G, and St3 steels by electrospark alloying using processing electrode from T15K6, VK8 hard alloys, as well as 45 and St3 steels (the “steel on steel” option), it was shown that the resulting surface layers are ~70% composed of the material steel substrate modified by electro-discharge treatment. The influence of the steel composition on the coefficients of the processing electrode material transfer on the substrate, on the roughness, microhardness, and wear resistance of the resulting surfaces has been studied. It is shown that the wear resistance of the resulting composites is determined mainly by the nature of the treated surface and, to a much lesser extent, by the processing electrode material, roughness, and microhardness of the surface.
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Kolařík, Ladislav, Miroslav Sahul, Marie Kolaříková, Martin Sahul, and Milan Turňa. "Resistance Spot Welding of Low Carbon Steel to Austenitic CrNi Stainless Steel." Advanced Materials Research 875-877 (February 2014): 1499–502. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.1499.
Повний текст джерелаАнотація:
The contribution deals with resistance spot welding of low carbon steel to austenitic CrNi stainless steel. The thickness of welded dissimilar steels was 2 mm. DeltaSpot welding gun with process tape was utilized for welding of the above-mentioned combination of steels. Resistance spot welds were produced under different welding currents. The welding currents used were 7 kA, 7.5 kA and 8 kA, respectively. Optical microscopy, microhardness measurement across the weld joint and EDX analysis across the weld joint interface were used to evaluate the quality of resistance spot welds of dissimilar steels.
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Hu, Min. "The Study on the Weldability of 1MnCrMoNi Alloy Steel and Q235 Carbon Steel." Key Engineering Materials 861 (September 2020): 71–76. http://dx.doi.org/10.4028/www.scientific.net/kem.861.71.
Повний текст джерелаАнотація:
In this paper, the weldability of 1mncrmoni alloy steel and Q235 carbon steel is studied. The microhardness, tensile strength, impact and other mechanical properties of the welded joint are tested by manual arc welding. The variation trend of microhardness, tensile strength and impact toughness of the welded joint under different welding methods is studied, which provides theoretical support for practical engineering application.
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Kucukomeroglu, T., and S. M. Aktarer. "Microstructure, microhardness and tensile properties of FSWed DP 800 steel." Journal of Achievements in Materials and Manufacturing Engineering 2, no. 81 (April 1, 2017): 56–60. http://dx.doi.org/10.5604/01.3001.0010.2038.
Повний текст джерелаАнотація:
Purpose: Dual phase (DP) steels are widely used in the automotive industry due to their properties of a high balance of strength and formability. However, it is known that conventional welding of high strength steel leads to some undesirable results such as hardness decrease in the heat affected zone. Friction stir welding (FSW) is a new solid state joining method, which is used to join these steels due to its advantage of low heat input. The aim of this study is to evaluate the microstructural change and mechanical properties of friction stir welded DP800 steel. Design/methodology/approach: DP 800 steels with 1.5 mm thickness were subjected to friction stir welding, by using a tungsten carbide (WC) tool. The tool was tilted 2°, and downforce of the tool was kept constant at 6 kN. During processing, the tool rotation and traverse speed were fixed at 1600 rpm and 170 mm∙min-1, respectively. Findings: The friction stir welded region comprises martensite, bainite, refined ferrite. The average microhardness of stir zone has increased from 260 HV0.2 to about 450 HV0.2. The tensile sample shows a decrease in the ultimate tensile strength (σUTS) about 3%, from 827 MPa to 806 MPa for the joint. The yield strength (YS) of the joint is about 566 MPa and the value is near that of DP800. Research limitations/implications: The tungsten carbide tool used for the friction stir welding has suffered deterioration in the pin profile after 1 meter welding operation. It may be advisable to drill a pre-hole in the specimens for a longer tool life. Practical implications: Tool wear for industrial applications will be a major problem. Therefore, the use of tools with high wear resistance such as polycrystalline cubic boron nitride may be recommended. Originality/value: Works on friction stir welding of dual phase steels are limited and they mostly focus on spot welding. Also, this study systematically investigates the microstructure and mechanical properties of dual-phase 800 steels after the friction stir welding.
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Ye, Jin Ling, and Feng Ye. "Effects of Strong Carbide-Forming Elements on Low Temperature Salt-Bath Chromizing." Advanced Materials Research 214 (February 2011): 646–50. http://dx.doi.org/10.4028/www.scientific.net/amr.214.646.
Повний текст джерелаАнотація:
The microstructure, phase structure, white layer thickness and chromium concentration, microhardness of the chromized layer of T10 steel and 3Cr2W8V steel by low temperature salt-bath chromizing with plasma nitriding are contrasted. The chromizing process is investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD). Results show that the strong carbide-forming elements (Cr, W, V) obstruct the diffusion of chromium and carbon, the white layer thickness and microhardness, surface chromium concentration of the chromized layer are reduced. A chromized layer of T10 steel with average 7.3μm in thickness, 84.47% in surface chromium concentration and 1300HV-1400HV in microhardness is formed on the substrate by chromizing at 610°C for 6h, as compared to the chromized layer of 3Cr2W8V steel with average 3.3μm in thickness, 74.27% in surface chromium concentration and 1200HV-1300HV in microhardness.
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Ji, Huiling, Yiwei Zhang, Wenzhao Lu, Bang Wei, and Xiaomin Yuan. "Effect of Hot Working Processes on Microstructure and Mechanical Properties of Pipeline Steel." Crystals 11, no. 8 (July 24, 2021): 860. http://dx.doi.org/10.3390/cryst11080860.
Повний текст джерелаАнотація:
The microstructure and microhardness of X70 pipeline steel were investigated after conducting different processing routes. The microstructure was characterized using optical and electron microscopy. Scanning electron microscopy equipped with electron backscattered diffraction (EBSD) and transmission electron microscopy techniques were applied for investigation of different thermal processing treatment conditions. Mechanical properties were characterized by a microhardness tester. The results show that the microstructure mainly consists of granular bainite, acicular ferrite and a small amount of M/A constituents under hot rolling states. There are many dislocations inside the acicular ferrite. The thermal simulation experiments show that the microstructure becomes homogeneous with the increase in cooling rate. The acicular ferrite morphology becomes fine and uniform, and the content of M/A constituents increases at the same compression amount. The compression gives rise to the accumulated strain and stored energy, which accelerate the transformation of acicular ferrite and refine the microstructure of the pipeline steel. The microhardness rises with the increase in deformation ratio and cooling rate. The microstructure of the pipeline steel subjected to the isothermal quenching process is ultrafine ferrite and M/A islands. When the isothermal quenching temperature reaches 550 °C, a small amount of upper bainite appears in the microstructure. With the increase in isothermal quenching temperature, the microhardness decreases. Acicular ferrite is a better candidate microstructure than ultrafine ferrite for the pipeline steels.
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Skakov, Mazhyn, Lyaila Bayatanova, and Michael Sheffler. "Changes of Structural-Phase Condition in 18CrNi3MoA-SH Steel After Elektrolyte-Plasma Processing." Advanced Materials Research 601 (December 2012): 74–78. http://dx.doi.org/10.4028/www.scientific.net/amr.601.74.
Повний текст джерелаАнотація:
The research shows the results of electrolyte-plasma treatment influence on structure-phase state, mechanical properties and wear-resistance of drilling tool steel samples. The comparative analysis of microstructure, microhardness and wear-resistance of the samples in initial state and after electrolyte-plasma treatment is represented. It was found out that 18CrNi3MoA-Sh steel microstructure has fine-grained martensite-bainite structure after the treatment. It was determined that 18CrNi3MoA-Sh steel possesses high wear-resistance after electrolyte-plasma treatment, so that technology is characterized by low power consumption and cost price. The initial state microhardness is 2800 MPa on the average. Microhardness on the bearing lane surface after electrolyte-plasma processing is 7500 MPa on the average. Microhardness increases in 2-2.5 times more before treatment that indicates the technology efficiency.
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Kurc-Lisiecka, A., and A. Lisiecki. "Laser welding of stainless steel." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 98 (January 1, 2020): 32–40. http://dx.doi.org/10.5604/01.3001.0014.0815.
Повний текст джерелаАнотація:
Purpose: of this paper was to analyze the influence of the basic parameters of laser welding (i.e. laser beam power and welding speed, as well as energy input) of butt joints of the 2.0 mm thick stainless steel AISI 304 sheets on the weld shape and joint quality. Design/methodology/approach: The preliminary trials of simulated laser welding by melting the austenitic stainless steel sheets (the so called bead-on-plate welding), as well as the welding of the test butt joints, were carried out using the high-power diode laser (HPDL) ROFIN DL 020, without the additional material (the technique of autogenous welding). A crucial parameter that determines both the mechanical properties and the corrosive resistance of a joint (the region of a weld and HAZ - heat affected zone) in the case of stainless steels with austenitic structure is energy input, which should be kept at a minimum, and at the same time full penetration and a proper shape of the fusion zone should be ensured. The investigations included the macrostructure and microstructure observations by light microscopy, researches of mechanical properties in a static tensile test and also microhardness measurements made by Vickers method. Findings: The results have shown that it is possible to provide a proper shape of the weld of fine-grained structure and narrow heat affected zone, but it requires careful selection of the welding parameters, especially a low energy input. The microhardness measurements showed that the in case of welding the butt joints using the high-power diode laser in HAZ area a slight increase in microhardness to approx. 185HV0.2 compared to base material (160-169HV0.2) and a decrease in microhardness in the fusion zone (FZ) to approx. 140- 150HV0.2 have been observed. All welded sample broke from the joint during the testing at tensile stress between 585 MPa and 605 MPa with corresponding percentage elongation in the range of 45-57%. It can be found that the joints strength is not less than the strength of the base metal of 2.0 mm thick AISI 304 austenitic stainless steel sheet. Research limitations/implications: Studies of the weldability of stainless steels indicate that the basic influence on the quality of welded joints and reduction of thermal distortions has the heat input of welding, moreover the highest quality of welded joints of austenitic stainless steel sheets are ensured only by laser welding. Practical implications: The laser welding technology can be directly applied for welding of austenitic steel AISI 304 sheets 2.0 mm thick. Originality/value: Application of high power diode laser for welding of austenitic stainless steel AISI 304.
Дисертації з теми "Microhardness of steel"
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Rose, Scott Anthony. "The Effect of Cooling Rate of Friction Stir Welded High Strength Low Alloy Steel." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4181.
Повний текст джерелаАнотація:
The friction stir welding of steel has produced a hard zone in several different alloys. Despite its detrimental effects on weld toughness, the reasons behind neither its formation nor a method of reducing its size or effects have been explored. Recent advances in process control allow for direct heat input control, which combined with the use of backing plates of different thermal conductivity allows for an expansion of the process window. These control methods also affect the HAZ cooling rate by providing greater range (a 60% increase compared to a fixed backing plate) and control (five welds within 16 °C/s). This increased range produced microstructures consisting of various forms of ferrite at lower cooling rates and bainite at higher cooling rates. The hard zone was determined to be the result of the formation of the bainite at higher cooling rates and was avoided by keeping the cooling rate below 20 °C/s in HSLA-65.
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Mecelis, Guilherme Rosati. "Caracterização mecânica e microestrutural de aços microligados processados industrialmente /." Ilha Solteira, 2017. http://hdl.handle.net/11449/151453.
Повний текст джерелаАнотація:
Orientador: Juno GallegoResumo: Os aços microligados são materiais já tradicionais e muito versáteis por suas propriedades mecânicas superiores, sendo sua evolução diretamente ligada com a otimização da composição química e do processamento termomecânico. É um tipo de aço que apresenta uma microestrutura refinada, alta resistência mecânica, boa usinabilidade e soldabilidade e tem substituído aços comuns por atingir essas propriedades mecânicas a partir de processos de fabricação mais baratos. Os aços estudados são comerciais, apresentam limite de escoamento entre 419 MPa e 646 MPa e grãos ferríticos finos com tamanhos inferiores a 3,70 μm. Neste trabalho são investigadas chapas industriais produzidas por laminação controlada, visando analisar a correlação entre a microestrutura ferrítico-perlítica e as propriedades mecânicas encontradas nas diferentes secções longitudinal, transversal e normal da chapa laminada. As diferenças entre as diferentes secções não são bem exploradas atualmente, então este estudo contribui para uma melhor compreensão da anisotropia introduzida pelo processamento termomecânico industrial. Foram feitas correlações entre as propriedades, confirmando a existência de diferenças estatisticamente significativas entre as secções, constatando que esses aços podem apresentar variações em suas propriedades de acordo com a secção de análise adotada. Foi confirmada a correlação de Hall-Petch nos aços estudados, e a influência dos mecanismos de endurecimento foi avaliada para estes materiais.
Abstract: Microalloyed steels are traditional materials and very versatile due to their superior mechanical properties, being its evolution directly linked with an optimization of the chemical composition and the thermomechanical processing. It is a type of steel that has a fine microstructure, high mechanical strength, good machinability and weldability, and has substituted common steels for achieving these mechanical properties with a cheaper manufacturing process. The studied steels are commercial and have yield strength between 419 MPa and 646 MPa and fine ferritic grains with size smaller than 3.70 μm. In this work are investigated industrial plates produced by controlled lamination, aiming to analyze the correlations between ferrit-perlitic microstructure and the mechanical properties found in the different sections of the hot rolled plate (longitudinal, transverse and normal). The differences between the different sections are not well explored, so this study contributes to a better understanding of the anisotropy introduced by industrial thermomechanical processing. Correlations were made between the properties, confirming the existence of significant differences between the different sections, finding that these steels may show different properties according to the section of analysis adopted. The Hall-Petch correlation was confirmed in the studied steels, and the influence of the hardening mechanisms was also evaluated.
Mestre
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Pessoa, AntÃnio Rodolfo Paulino. "Welding on UNS S32750 superduplex stainless steel plates employed FCAW process." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14415.
Повний текст джерелаАнотація:
AgÃncia Nacional do PetrÃleoSuperduplex stainless steels (SDSS) may be defined as a family of steels having a two-phase ferritic-austenitic microstructure and the good mechanical properties and high corrosion resistance of this alloy are attributed to this microestrutural balance. These excellent qualities attribute to SDSS great employability in the oil sector, where manufacturing and equipment maintenance are performed by welding, which if not executed properly, can have a negative effect on the metallurgical properties and this problem becomes more critical in multipass welding due to repeated thermal cycles. Among the several welding processes employed in the welding of SDSS, fell to this work was to evaluate the FCAW process in multipass welding joints of SDSS UNS S32750, regarding the selection of appropriate welding parameters and the influence of these parameters on microstructural transformations, mechanical properties and corrosion resistance of welded joints. Then, this work was divided into three steps: Stage 1 was the characterization of the base metal in as-received condition. In Stage 2, weldings were accomplished using a bead on plate (BOP) technique to determine the control factors and their levels to be used in the subsequent stage, in which an experimental design was conducted by Taguchi method with Alloy, Stick out, Shielding gas, welding gun orientation, Arc oscillation, Energy technique and Heat input used as control factors and quality characteristics were evaluated the ratio R/L, bead penetration, ferrite content and inclusions content and microhardness. Finally, in Stage 3 were performed multipass welding in joints and afterwards was executed: A microstructural characterization in three regions of Fusion Zone (Root, Filler and Cap) and Heat Affected Zone by Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) and were also performed a measurement of the ferrite content; measurement of inclusions content; microhardness tests and Critical Temperature Pitting (CPT) tests according to ASTM G150. The results showed, ferrite contents ranging from 44% and 54.9% and their highest values were observed when employed the alloy 2507, heat input of 1.6 kJ/mm and pulsed current. The lowest inclusions contents were obtained by using of shielding gas with the mixture of 96%Ar + 4%CO2 (Stage 2) and heat input of 1,6kJ/mm (Stage 3). The microhardness values in FZ of joints were not affected significantly by any of the control factors. Already, the results of CPT tests showed that pits nucleated preferentially within α, at α/γ grain boundaries and at interfaces areas between large diameter inclusions and the metallic matrix and propagated predominantly into α phase. The CPT values ranging from 47 ÂC to 78 ÂC, with highest were obtained for the alloy 2507, heat input of 1.6 kJ/mm and continuous current into Root region and for the alloy 2507, heat input of 1.6 kJ/mm and the pulsed current in Filler and Cap regions. From the three regions of FZs, the Root showed the best results with no defects, satisfactory ferrite contents, lowest inclusions contents and highest CPT values.
Os aÃos inoxidÃveis superduplex (AISDs) possuem uma microestrutura bifÃsica constituÃda por ferrita (α) e austenita (γ) e quando devidamente balanceadas conferem ao material, boas propriedades mecÃnicas e elevada resistÃncia à corrosÃo. Qualidades que atribuem aos AISDs grande empregabilidade no setor petrolÃfero, onde a fabricaÃÃo e manutenÃÃo de equipamentos sÃo realizadas por soldagem e se executada inadequadamente, pode afetar negativamente as propriedades destes aÃos, o que se torna mais crÃtico quando hà a imposiÃÃo de inÃmeros ciclos tÃrmicos durante uma soldagem multipasse. Dentre os inÃmeros processos de soldagem utilizados na soldagem dos AISDS, coube a este trabalho avaliar o processo arame tubular na soldagem multipasse em juntas do AISD UNS S32750, levando em consideraÃÃo a seleÃÃo dos parÃmetros de soldagem adequados, bem como a influÃncia destes parÃmetros nas alteraÃÃes microestruturais, microdureza e resistÃncia à corrosÃo das juntas soldadas. Desta forma, dividiu-se este trabalho em trÃs etapas: A Etapa 1 consistiu na caracterizaÃÃo do metal de base na condiÃÃo como recebido. Jà na Etapa 2 foram realizadas soldagens por simples deposiÃÃo para selecionar os fatores de controle e seus nÃveis a serem utilizados na etapa posterior, e o planejamento experimental foi realizado pelo mÃtodo Taguchi com a Liga, GÃs, DBCP, TÃcnica da Tocha, Tecimento, TÃcnica de Energia e Energia foram utilizados como fatores de controle e como variÃveis de resposta escolheu-se a razÃo R/L, a penetraÃÃo, a fraÃÃo de ferrita, a fraÃÃo das inclusÃes e a microdureza. E por fim, na Etapa 3 foram realizadas soldagens multipasse em juntas e posteriormente efetuou-se: uma caracterizaÃÃo microestrutural em trÃs regiÃes da Zona Fundida (Raiz, Enchimento e Acabamento) e Zona Afetada pelo Calor atravÃs de Microscopia Ãtica (MO) e Microscopia EletrÃnica de Varredura (MEV) e Espectroscopia de Energia Dispersiva de Raios X (EDS); quantificaÃÃo da fraÃÃo de ferrita; quantificaÃÃo da fraÃÃo das inclusÃes; ensaios de microdureza e uma avaliaÃÃo da resistÃncia à corrosÃo por pites atravÃs dos ensaios de temperatura crÃtica de pite (CPT) seguindo a norma ASTM G150. Como resultados, obteve-se fraÃÃes de ferrita entre 44% e 54,9% com seus maiores valores observados quando utilizou-se a liga 2507, a energia de 1,6 kJ/mm e a corrente contÃnua pulsada. As menores fraÃÃes das inclusÃes foram obtidas pela utilizaÃÃo do gÃs de proteÃÃo com 96%Ar + 4%CO2 (Etapa 2) e da energia de 1,6kJ/mm (Etapa 3). As microdurezas na ZF das juntas nÃo apresentaram diferenÃas significativas. Jà os ensaios de CPT revelaram que os pites nuclearam preferencialmente no interior da α, nos contornos α/γ e nas interfaces entre inclusÃes de grande diÃmetro e a matriz metÃlica, propagando-se exclusivamente atravÃs da α. Os valores de CPT apresentaram uma faixa de 47ÂC à 78ÂC, com os maiores valores obtidos para a liga 2507, a energia de 1,6 kJ/mm e a corrente contÃnua constante na regiÃo da Raiz e nas regiÃes do Enchimento e Acabamento ao utilizar-se a liga 2507, a energia de 1,6 kJ/mm e a corrente contÃnua pulsada. Dentre as trÃs regiÃes das ZFs, a Raiz apresentou os melhores resultados com ausÃncia de defeitos, fraÃÃes de ferrita satisfatÃrias, menores fraÃÃes das inclusÃes e maiores valores de CPT.
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Kivisäkk, Ulf. "Influence of hydrogen on corrosion and stress induced cracking of stainless steel." Doctoral thesis, KTH, Korrosionslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12436.
Повний текст джерелаАнотація:
Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. Some aspects of the effect of hydrogen on corrosion and hydrogen-induced stress cracking, HISC, of stainless steels were studied in this work. These aspects relate to activation of test specimens for uniform corrosion testing, modification of a test cell for dewpoint corrosion testing and the mechanism of hydrogen-induced stress cracking. The results from uniform corrosion testing of superduplex stainless steels indicated that there is a large difference between passive and activated surfaces in hydrochloric acid and in lower concentrations of sulphuric acid. Hence, initial activation of the test specimen until hydrogen evolution can have a large influence on the results. This may provide another explanation for the differences in iso-corrosion curves for superduplex stainless steels that have previously been attributed to alloying with copper and/or tungsten. In concentrated sulphuric acid, potential oscillations were observed; these oscillations activated the specimen spontaneously. Due to these potential oscillations the influence of activation was negligible in this acid. An experimental set-up was developed for testing dewpoint corrosion of stainless steels in a condensate containing 1 % hydrochloric acid. There was an existing experimental set-up that had to be modified in order to avoid azeotroping of the water and hydrogen chloride system. A separate flask with hydro chloric acid was included in the experimental set-up. The final set-up provided reasonably good agreement with field exposures in contrary to much higher corrosion rates in the original set-up. Relaxation and low temperature creep experiments have been performed with several stainless steels in this work. The aim was to understand how creep and relaxation relates to material properties and the relative ranking between the tested materials. For low temperature creep with a load generating stresses below the yield strength, as well relaxation at stress levels above and below the yield strength, the same ranking with respect to changes in mechanical properties of the steel grades was found. For low temperature creep with a load level above the yield strength, the same ranking was not obtained. This effect can most probably be explained by annihilation and generation of dislocations. During low temperature creep above the yield strength, dislocations were generated. In addition, low temperature creep experiments were performed forone superduplex stainless steel in two different product forms with differentaustenite spacing in the microstructure. The superduplex material experienced low temperature creep at a lower load level for the material with large austenite spacing compared to the one with smaller austenite spacing. Also this differenceis influenced by dislocations. In a material with small austenite spacing the dislocations have more obstacles that they can be locked up against. Studies of the fracture surfaces of hydrogen induced stress cracking, HISC, tested duplex stainless steels showed that HISC is a hydrogen-enhanced localised plasticity, HELP, mechanism. Here a mechanism that takes into account the inhomogeneous deformation of duplex stainless steels was proposed. This mechanism involves an interaction between hydrogen diffusion and plastic straining. Due to the different mechanical properties of the phases in a superduplex stainless steel, plastic straining due to low temperature creep can occur in the softer ferrite phase. A comparison between low temperature creep data showed that for the coarser grained material, HISC occurs at the load levelwhen creep starts. However, in the sample with small austenite spacing, HISC did not occur at this load level. Microhardness measurements indicated that the hydrogen level in the ferrite was not high enough to initiate cracking in the coarser material. The proposed mechanism shows that occurrence of HISC is an interaction between local plasticity and hydrogen diffusion.QC20100618
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Balogun, Nurudeen. "The Microstructure, Tensile Deformation, Cyclic Fatigue and Final Fracture Behavior of Alloy Steel 4140 for use in CNG (Compressed Natural Gas) and Hydrogen Pressure Vessels." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1290227797.
Повний текст джерела
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Bertilsson, Anders. "Alternative welding methods for nitrogen alloyed steel." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-62142.
Повний текст джерелаАнотація:
This project explores the feasibility of the solid-state welding method direct-drive friction welding to be used as a joining method for the nitrogen alloyed steel Uddeholm Vanax SuperClean, produced via processes based on powder metallurgy. Vanax SuperClean cannot be welded using fusion welding methods where the base material melts, due to nitrogen escaping the material, resulting in inferior quality welds. The cost of the material motivates the use of Vanax SuperClean for critical parts in applications, combined with a less costly material for the remaining parts, causing alternative joining methods to be examined. Vanax SuperClean is friction welded to itself and to Uddeholm steel types Stavax ESR and UHB 11. Samples are prepared for a number of examinations. Microstructures of the samples are examined using microscopy, microhardness testing is carried out per the Vickers principle, retained austenite is measured using X-ray diffraction and tensile testing of the welded samples is performed. Defect-free welds are produced in all examined samples, showing that the method is suitable for Vanax SuperClean and that no preheating or slow cooling of workpieces are necessary. The possibility of using friction stir welding as a joining method for Vanax SuperClean is discussed.Detta projekt undersöker möjligheten att använda trycksvetsningsmetoden friktionssvetsning som sammanfogningsmetod för det kvävelegerade pulvermetallurgiskt framställda stålet Uddeholm Vanax SuperClean. Vanax SuperClean kan inte svetsas med smältsvetsmetoder där grundmaterialet smälter, på grund av kvävgasbildning som resulterar i undermåliga svetsfogar. Kostnaden för materialet motiverar användandet av Vanax SuperClean för kritiska delar i applikationer, kombinerat med ett mindre kostsamt material till övriga delar, vilket föranleder undersökning av alternativa sammanfogningsmetoder. Vanax SuperClean friktionssvetsas mot sig själv, såväl som mot Uddeholmsstålen Stavax ESR och UHB 11. Prov tas fram för ett antal undersökningar. Mikrostruktur undersöks med mikroskopi, mikrohårdhetsprovning utförs enligt Vickersprincipen, restaustenitnivåer mäts med röntgendiffraktion och dragprovning utförs. Lyckade svetsfogar fås i alla undersökta prover, vilket visar att svetsmetoden är lämplig för Vanax SuperClean och att varken förvärmning eller långsamt svalnande av arbetsstycken krävs. Möjligheten att använda friktionsomrörningssvetsning som sammanfogningsmetod för Vanax SuperClean diskuteras.
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Nunes, Everton Barbosa. "âPROPRIEDADES MECÃNICAS E CARACTERIZAÃÃO MICROESTRUTURAL NA SOLDAGEM DO AÃO INOXIDÃVEL DUPLEX UNS S31803 (SAF 2205)â." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=3918.
Повний текст джерелаАнотація:
AgÃncia Nacional do PetrÃleoFundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico
Os aÃos inoxidÃveis duplex possuem boas propriedades mecÃnicas e excelente resistÃncia à corrosÃo, aumentando seu uso em ambientes agressivos. Estas caracterÃsticas os fazem muito utilizados principalmente na indÃstria quÃmica e petroquÃmica. Geralmente, a fabricaÃÃo e reparo destes equipamentos envolvem operaÃÃes de soldagem, sendo que à muito importante avaliar a influÃncia dos parÃmetros de soldagem multipasse no balanceamento de fases, na microestrutura e microdureza. Primeiramente, foram realizadas soldagens em aÃo ASTM A516 Gr. 60 com eletrodo revestido AWS 2209-17, empregando diversas energias, variando a velocidade e corrente de soldagem. Foi feita a caracterizaÃÃo microestrutural atravÃs de microscopia Ãptica, quantificaÃÃo do teor de ferrita utilizando ferritoscÃpio e ensaio de microdureza para avaliar o metal de solda. Posteriormente, foram selecionadas as melhores condiÃÃes da etapa anterior para soldagem do aÃo inoxidÃvel duplex UNS S31803 para avaliar o efeito da energia de soldagem no balanceamento de fases, na microestrutura e microdureza no metal de solda e ZAC. Na Ãltima etapa foram realizadas soldagens em juntas de aÃo duplex, de modo a avaliar o efeito da energia de soldagem e restriÃÃo da junta no balanceamento de fases, microestrutura, microdureza e tenacidade do metal de solda e da ZAC. Foi verificada a influÃncia da energia de soldagem no teor de ferrita, possuindo comportamentos diferentes de acordo com os parÃmetros de soldagem. As microestruturas bÃsicas da austenita formada foram alotrimÃrfica, WidmanstÃtten e intragranular. Nas regiÃes com sobreposiÃÃo de passe houve maior quantidade de austenita no metal de solda e microestrutura mais refinada na ZAC. Foi observado que quanto maior a velocidade de soldagem, maior a quantidade de WidmanstÃtten. De forma geral, foi observado menor nÃvel de microdureza no metal de solda, principalmente nas condiÃÃes com maior quantidade de austenita WidmanstÃtten. A restriÃÃo da junta soldada influenciou no balanceamento de fases e na tenacidade da ZAC. NÃo houve efeito da energia de soldagem na tenacidade do metal de solda, possuindo nÃveis menores em relaÃÃo ao material como recebido
Duplex stainless steels show good mechanical properties and excellent corrosion resistance. These qualities are increasing their use in aggressive environments. Thus, these characteristics make them very used in chemical and petrochemical, mainly. Generally, the manufacture and repair of any industrial equipment involve welding operations, even though it is very important to evaluate the influence of multipass welding parameters in phase balances, microstructure and microhardness. Firstly, the shielded metal arc welding in steel ASTN A516 Gr. 60 with electrode AWS 2209-17 had been carried through with many energies, varying welding speed and current. Microstructural characterization by optic microscopy, quantification of ferrite content using ferritscope and microhardness test has being performed to evaluate the weld metal. After that, the best conditions of the last stage for welding of duplex stainless steel UNS S31803 had been chosen to evaluate the effect of the welding energy in phase balances, microstructure, and microhardness in the weld metal and HAZ. In the last stage, the weldings in joint of duplex steel had been carried through, in order to evaluate the effect of the welding energy and restriction of joint in phase balances, microstructure, microhardness and toughness of the weld metal and HAZ. The influence of the welding energy in the ferrite content was checked, although the behavior was different according to variation of the welding parameters. The basic microstructures of formed austenitic were allotriomoph, WidmanstÃtten and intragranular. Regions with pass overlapping presented greater amount of austenite in the weld metal and microstructure more refined in the HAZ. It was observed that increasing welding speed, greater is the amount of WidmanstÃtten austenite. In general, the increase of the amount of WidmanstÃtten austenite decreases level of microhardness in the weld metal. The restriction of the welded joint influenced in phase balances and toughness of the HAZ. There was not effect of the welding energy on toughness of the weld metal and this region occurred higher levels in relation to material as received
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Kaijalainen, A. (Antti). "Effect of microstructure on the mechanical properties and bendability of direct-quenched ultrahigh-strength steels." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526213491.
Повний текст джерелаАнотація:
Abstract The effect of austenite pancaking in the non-recrystallisation regime on microstructure and mechanical properties, especially bendability, was investigated in direct-quenched ultrahigh-strength strip steels with martensitic-bainitic microstructures. Lowering the finishing rolling temperature (FRT) increased total reduction in the non-recrystallisation region (R tot). Niobium microalloying increased Rtot while variations in C, Mn and Mo did not affect Rtot to the same extent as Nb. A decrease in the FRT increased the incidence of softer microstructures such as ferrite and granular bainite in the subsurface layers. The microstructures at the centreline were comprised of auto-tempered martensite with some bainite. An increase in Rtot strengthens the intensities of the ~{554}<225>α and ~{112}<110>α texture components at the centreline and the components ~{112}<111>α and ~{110}<112>α - {110}<111>α at the strip subsurface. Bendability is poorer with the bend axis perpendicular rather than parallel to the rolling direction (RD) and is further impaired with increasing hardness below the sheet surface. An intense ~{112}<111>α shear texture combined with upper bainite containing MA islands in the subsurface region is shown to be detrimental to bendability when the bend axis is perpendicular to the RD. This anisotropy of bendability can be explained by the appearance of geometric softening in grain clusters belonging to this texture component when the bend axis is perpendicular to the RD. Shear localisation is prevented, however, by the presence of a sufficiently thick subsurface microstructure having adequate work hardening capacity, i.e., ferrite + granular bainite rather than ferrite + upper bainite. The strain required to initiate strain localisation can be increased and good bendability thereby achieved—even in the presence of detrimental texture components—by ensuring the presence of a sufficiently soft subsurface layer extending to a depth of approximately 5% of the total sheet thickness. The above beneficial microstructures can be obtained and good bendability ensured in direct-quenched strip steel with a yield stress above 900 MPa together with good impact toughness, provided a suitable combination of chemical composition and processing parameters is selected and sufficient attention is paid to steelmaking operations to obtain a proper inclusion structureTiivistelmä Austeniitin muokkauksen vaikutusta mikrorakenteeseen ja mekaanisiin ominaisuuksiin, erityisesti särmättävyyteen, tutkittiin suorasammutetuilla martensiittis-bainiittisilla suurlujuusnauhateräksillä. Kuumavalssauksen lopetuslämpötilan lasku kasvatti austeniitin kokonaisreduktiota ei-rekristallisaatioalueella. Mikroseostus niobilla kasvatti myös kokonaisreduktiota, kun taasen muutokset C-, Mn- ja Mo -pitoisuuksissa eivät vaikuttaneet yhtä voimakkaasti. Valssauksen lopetuslämpötilan lasku kasvatti pehmeämpien mikrorakenteiden, kuten ferriitin ja granulaarisen bainiitin, määrää nauhan pintakerroksessa. Terästen keskilinjan mikrorakenteet koostuivat pääasiassa itsepäässeestä martensiitista sekä pienestä määrästä bainiittia. Kokonaisreduktion kasvu voimisti ~{554}<225>α - ja ~{112}<110>α -tekstuurikomponentteja keskilinjalla sekä ~{112}<111>α- ja ~{110}<112>α - {110}<111>α -komponentteja nauhan pintakerroksessa. Särmättävyys oli huonompi särmän ollessa poikittain valssaussuuntaan nähden kuin pitkittäin. Pintakerroksen kovuuden kasvu heikensi särmättävyyttä. Pintakerroksen voimakas ~{112}<111>α -leikkaustekstuuri, yläbainiitin ja MA-saarekkeiden läsnä ollessa, osoittautui haitalliseksi särmän ollessa poikittain valssaussuuntaan nähden. Särmättävyyden anisotrooppisuus voidaan selittää geometrisella pehmenemisellä rakeissa, joissa kyseinen tekstuurikomponentti on voimakas. Leikkausmyötymän paikallistuminen estyy, kun pinnassa on riittävän paksu hyvän muokkauslujittumiskyvyn omaava kerros, mikä sisältää esim. ferriittiä ja granulaarista bainiittia, mutta ei ferriittiä ja yläbainiittia. Särmättävyys osoittautui pysyvän hyvänä huolimatta haitallisesta tekstuurikomponentista, kun pehmeä pintakerros ulottui noin 5 % syvyydelle levyn paksuudesta. Edellä mainitut mikrorakenteet ja hyvä särmättävyys voidaan saavuttaa suorasammutetuilla yli 900 MPa myötölujuuden nauhateräksillä yhdessä hyvän iskusitkeyden kanssa, kunhan valitaan sopiva kemiallisen koostumuksen ja valmistusparametrien yhdistelmä sekä kiinnitetään huomiota teräksen sulkeumapuhtauteen
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Rozum, Jakub. "Chemicko-tepelné zpracování ocelí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417098.
Повний текст джерелаАнотація:
This thesis deals with study of surface layers of low-carbon steels formed by chemical-heat treatment. The first three chapters consist of theoretical part of the thesis, there are explained basic physical principles of these technologies and described individual types, the third chapter deals with the application of chemical-heat treated low-carbon steels in mechanical engineering. The experimental part of thesis deals with analysis of surface layers of two low-carbon steels formed using plasma nitrocarburizing and gas nitrocarburizing. The properties of these layers are evaluated based on the results of mechanical tests (hardness tests) and observation of microstructure. The thesis is completed by discussion, where the achieved results are evaluated.
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Silva, Gustavo Rodrigues da. "Caracterização magnética de aço com a superfície endurecida." reponame:Repositório Institucional da UCS, 2010. https://repositorio.ucs.br/handle/11338/569.
Повний текст джерелаАнотація:
Neste trabalho foram investigadas as propriedades magnéticas (curva de histerese e ruído Barkhausen) de alguns aços (ABNT 1045, 1050 e 1548) cujas superfícies foram endurecidas por indução. O objetivo era de desenvolver um ensaio não-destrutivo para determinar a espessura da camada endurecida, assim evitando a necessidade de realizar medidas (destrutivas) de microdureza. Medidas da susceptibilidade magnética mostraram um pico (ferrita) em torno de 800 A/m e outro (martensita) em torno de 3500 A/m. Assim procuramos correlacionar a amplitude do pico de ferrita com a espessura da camada dura na superfície. Para esta finalidade foram desenvolvidos sensores para medir ruído Barkhausen e um filtro para o processamento do sinal. Foi possível correlacionar medidas de microdureza com algumas características observadas nas medições magnéticas, como, por exemplo, a amplitude do sinal de ruído Barkhausen e o campo magnético do pico do sinal Barkhausen. Deste modo, encontrou-se uma relação entre a amplitude do ruído Barkhausen e a espessura da camada superficial. Seria desejável complementar essas medidas com outras e sugestões para uma continuação do trabalho são detalhadas.Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-03T20:29:34Z No. of bitstreams: 1 Dissertacao Gustavo Rodrigues da Silva.pdf: 8142476 bytes, checksum: 29c4748e15d0fbcc852d788b9f1fa011 (MD5)
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This work investigates the magnetic properties (hysteresis loop and Barkhausen noise) in some steels (ABNT 1045, 1050 and 1548) whose surfaces had been hardened by induction. The goal was to develop a non-destructive test procedure to determine the thickness of the hardened layer, thus avoiding the need to perform (destructive) measurements of the microhardness. Measurements of the magnetic susceptibility showed a peak (ferrite) around 800 A / m and other (martensite) at around 3500 A / m. Therefore, a correlation was sought between the peak amplitude of ferrite with the thickness of hard layer on the surface. For this purpose sensors were developed to measure Barkhausen noise as well as a filter for signal processing. It was possible to correlate measurements of microhardness with some features observed in magnetic measurements, for example, the amplitude of the Barkhausen noise and magnetic field of peak Barkhausen signal. Thus, a relationship was found between the amplitude of the Barkhausen noise and the thickness of the surface layer. It would be desirable to supplement these with other measurements and suggestions for further work are detailed.
Частини книг з теми "Microhardness of steel"
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Rizlan, Muhamad Zulkhairi, Ahmad Baharuddin Abdullah, and Zuhailawati Hussain. "Microstructure Observation and Microhardness Study of Friction Stir Welded Blank of Aluminum to Steel." In Advanced Structured Materials, 157–67. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92964-0_16.
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Kumar, Anjani, Rana Kumar Singh, Rahul Rathore, and Anil Kumar Das. "Microstructure and Microhardness Characteristics of TiC–TiN Ceramics Coating by TIG Process on Mild Steel." In Advances in Mechanical Engineering, 467–74. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-0124-1_42.
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Ma, Guohong, Xiaokang Yu, Jian Li, and Yinshui He. "Effect of Transverse Ultrasonic Vibration on MIG Welded Joint Microstructure and Microhardness of Galvanized Steel Sheet." In Transactions on Intelligent Welding Manufacturing, 109–18. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-7418-0_7.
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Wang, Xiaonan, Xiaming Chen, Wenping Weng, Hiromi Nagaumi, and Jingzhe Zhou. "Effect of Nickel Foil Thickness on Microstructure and Microhardness of Steel/Aluminium Alloy Dissimilar Laser Welding Joints." In Light Metals 2019, 385–93. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05864-7_49.
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Ali, Sadaqat, Ahmad Majdi Abdul Rani, Khurram Altaf, Patthi Hussain, Chander Prakash, Sri Hastuty, Tadimalla Varaha Venkata Lakshmi Na Rao, Abdul’Azeez Abdu Aliyu, and Krishnan Subramaniam. "Investigation of Alloy Composition and Sintering Parameters on the Corrosion Resistance and Microhardness of 316L Stainless Steel Alloy." In Lecture Notes in Mechanical Engineering, 532–41. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-16943-5_45.
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Mane, Sandip, and Sanjay Kumar. "Effect of Cutting Parameters on Microhardness in Turning of AISI 52100 Hardened Alloy Steel with Multilayer Coated Carbide Insert." In Proceedings of International Conference on Intelligent Manufacturing and Automation, 177–86. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4485-9_19.
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Ali, Sadaqat, Ahmad Majdi Abdul Rani, Muhammad Al’Hapis Abdul Razak, Abdul Azeez Abdu Aliyu, and Krishnan Subramaniam. "The Impact of Sintering Dwell Time on Nitrogen Absorption, Densification and Microhardness of 316L Stainless Steel Using Powder Metallurgy." In Advanced Structured Materials, 235–42. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-46036-5_22.
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Kumar, Anjani, Neeraj Singh, Sonu Nagar, and Anil Kumar Das. "Microstructural and Microhardness Analysis of Nickel-Based Ceramic Composite Coating on AISI 304 Stainless Steel by TIG Coating Method." In Proceedings of International Conference in Mechanical and Energy Technology, 111–19. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2647-3_11.
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Tayier, Walisijiang, Shamini Janasekaran, and Abdullah Hussein Ali Alzubydi. "The Influence of Welding Parameters on the Microhardness of Zincalume Steel Welded Joint Using Taguchi Technique in Metal Inert Gas (MIG)." In Lecture Notes in Mechanical Engineering, 315–21. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5753-8_29.
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Poelt, P., and A. Fian. "Steels, Carbon Concentration, and Microhardness." In Modern Developments and Applications in Microbeam Analysis, 201–5. Vienna: Springer Vienna, 1998. http://dx.doi.org/10.1007/978-3-7091-7506-4_28.
Повний текст джерелаТези доповідей конференцій з теми "Microhardness of steel"
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Santos, Rogério Felício dos, Ernane Rodrigues da Silva, André Rezende Figueiredo Oliveira, Henara Lillian Costa, and Alberto Arnaldo Raslan. "SURFACE MICROHARDNESS OF AISI 4140 STEEL NITRIDED DURING ELECTRIC DISCHARGE MACHINING." In 2nd International Brazilian Conference on Tribology. São Paulo: Editora Blucher, 2014. http://dx.doi.org/10.5151/1472-5836-25756.
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Kishawy, Hossam A., and Mohamed A. Elbestawi. "Effect of Process Parameters on Chip Morphology When Machining Hardened Steel." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-1130.
Повний текст джерелаАнотація:
Abstract This paper presents an experimental study of the effect of process parameters on chip morphology when machining hardened steel. Cutting tests are performed using ceramic inserts at (90–200) m/min cutting speed, (0.01–0.2) mm feed and (0.2–4) mm depth of cut. The chips obtained are examined using SEM and optical microscope. The effect of tool wear and different combinations of cutting speed and feed on chip morphology are studied. In addition, the effects of cutting conditions on chip segmentation frequency are investigated. Microhardness tests are also performed on the chips collected at different cutting conditions. The results obtained show that the cutting process parameters alter significantly the chips microhardness distribution.
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Gourlaouen, V., E. Verna, and P. Beaubien. "Influence of Flame Parameters on Stainless Steel Coatings Properties." In ITSC 2000, edited by Christopher C. Berndt. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.itsc2000p0487.
Повний текст джерелаАнотація:
Abstract Owing to high particle velocity upon impact, and consequently low porosity and high bond strength of so-obtained coatings, HVOF spraying process is widely used to improve components life in service. However, many parameters can affect metallic coatings properties, especially un-melted particles and oxidation level. Flame parameters, such as calorific power, combustion ratio and temperature, are of prime importance. The aim of this work was focused on the influence of these parameters on stainless steel coatings characteristics. For different substrate temperatures, maintained through CO2 cooling nozzles, those parameters varied independently. Flame characteristics were computed using a simple model for propylene as fuel gas. Microstructure investigation as well as oxide content measurements and microhardness were obtained. It appeared that combustion temperature, in the range studied (2600-2750K) was not a critical factor. However, combustion ratio and calorific power greatly influenced coating properties: an increase of oxide content, and consequently a higher microhardness, was observed when combustion ratio decreased as well as when calorific power increased.
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Melnikova, E. A., and A. A. Son. "Investigation of Microhardness and Strength Characteristics of Steel 16Cr12V2FTaR Subjected to Ultrasound Treatment." In 2005 International Conference Modern Technique and Technologies (MTT 2005). IEEE, 2005. http://dx.doi.org/10.1109/spcmtt.2005.4493223.
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Bogdanov, A. V., N. V. Grezev, S. A. Shmelev, M. A. Murzakov, and Yu V. Markushov. "Increasing microhardness and hardening depth of grade 2 wheel steel using fiber lasers." In XLIII ACADEMIC SPACE CONFERENCE: dedicated to the memory of academician S.P. Korolev and other outstanding Russian scientists – Pioneers of space exploration. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5133362.
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Li, HongLiang, Duo Liu, Zhi Wang, Ning Guo, and JiCai Feng. "An Analysis of Microstructure and Microhardness Distribution in Underwater Wet Welding of 304L Austenitic Stainless Steel to Low Alloy Steel 16Mn." In ASME 2018 13th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/msec2018-6434.
Повний текст джерелаАнотація:
In this study, underwater wet welding of 304L austenitic stainless steel to 16Mn low alloy steel was carried out using self-shielded flux-cored wires at a water depth of 0.3 m. The welds were produced using commercially obtained ER308 filler and specially developed nickel-based tubular wire. Microstructure and microhardness of wet welded joints have been particularly analyzed. The interface between austenitic weld metal and ferritic base metal was also discussed in detail. A robust weld of 304L/16Mn joint could be achieved by FCAW process using nickel-based tubular wire. Commercially obtained ER308 consumables failed to acquire sound welded joints due to large amount of slag remained in the groove. Ni-based weld metal was fully austenitic with well-developed columnar sub-grains while ER308 weld metal consisted of d-ferrite with different morphologies in the austenitic matrix. Type II boundary existed between austenitic weld metal and ferritic base metal. Compared to ER308 weld metal, Ni-based weld metal possessed the ability to be diluted by 16Mn base metal. Maximum hardness values in wet welding appeared in coarse-grained heat affected zone instead of transition zone for both consumables. Austenitic stainless steel welded joints exhibited high microhardness in the transition zone of 16Mn side, which was strongly diluted by ferritic base metal.
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Wei, Shaopeng, Gang Wang, Zilin Huang, Peng Wen, and Yiming Rong. "Effect of Multi-Layer Laser Heating on the Microstructure and Microhardness of Laser Hot-Wire Deposited FV520B Steel." In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8580.
Повний текст джерелаАнотація:
The mechanical and microstructural properties of FV520B martensitic stainless steel fabricated by laser hot-wire deposition are presented. An investigation based on experimental method was conducted to analyze the development of microstructure and microhardness under multiple laser heating. Multiple layers were cladded on the surface of martensitic stainless steel FV520B by fiber laser. A defect-free and high forming quality coatings were obtained. The microstructure of clad layer and heat affected zone was characterized using an optical microscope, SEM and EBSD. The gradient microhardness from the cladding layer to the substrate was tested. Subsequently, the effect of thermal history under multi-layer laser heating on the microstructure and microhardness was analyzed. Results indicate that the hardening trend in the coating/substrate interface and softening trend in the heat affected zone under laser heating. The tempering effect of the following-layer laser heating facilitates the reprecipitation of the hardening phases in heat affected zone.
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Maier, Galina, Elena Astafurova, Eugene Melnikov, Valentina Moskvina, Nina Galchenko, Alexander Smirnov, and Vladimir Bataev. "Microhardness homogeneity and microstructure of high-nitrogen austenitic steel processed by high-pressure torsion." In PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2017 (AMHS’17). Author(s), 2017. http://dx.doi.org/10.1063/1.5013810.
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Vorontsov, A. V., T. A. Kalashnikova, and A. N. Ivanov. "Laser-arc hybrid welding of 321 stainless steel: Structure and microhardness of weld metal." In PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5132253.
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Murzin, S. P., A. A. Melnikov, M. V. Blokhin, V. M. Reshetov, and I. A. Dyagovtsov. "Use of diffractive optics for structures formation in dual-phase steel with reduced microhardness." In 2021 International Conference on Information Technology and Nanotechnology (ITNT). IEEE, 2021. http://dx.doi.org/10.1109/itnt52450.2021.9649397.
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