The Experts below are selected from a list of 59655 Experts worldwide ranked by ideXlab platform
Huazhong Zhao - One of the best experts on this subject based on the ideXlab platform.
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Effect of high magnetic field on the pearlite transformation of Al-containing steel
Materials Science and Technology, 2017Co-Authors: Rui Xin, Wu Kaiming, Zhang Guohong, T. P. Hou, Wenwei Qiao, Huazhong ZhaoAbstract:ABSTRACTComparative studies were carried out on the effect of high magnetic field on the pearlite transformation of Al-containing high carbon Steels under the furnace slow cooling condition. For 1.37Al-bearing high carbon steel, the amount of pearlite was only 6 ± 3 vol.-% without magnetic field, whereas full pearlite was obtained under a 12-T high magnetic field. For free-Al high carbon steel, no pearlite transformation occurred, whereas lots of bainite were formed under a 12-T high magnetic field. In addition, the interlamellar spacing of pearlite increased from 100 ± 7 to 112 ± 18 nm by the application of a 12-T magnetic field. It has been proved that the pearlite transformation of high carbon steel was promoted by high magnetic field and by the addition of aluminium.
P E J Riveradiazdelcastillo - One of the best experts on this subject based on the ideXlab platform.
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stability of retained austenite in martensitic high carbon Steels part i thermal stability
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Wen Cui, D Sanmartin, P E J RiveradiazdelcastilloAbstract:Abstract Thermal stability of retained austenite in 1C-1.5Cr Steels with two Si and Mn contents is studied. Time-resolved high resolution synchrotron X-ray radiation and dilatometry are employed. The threshold transformation temperatures, decomposition kinetics, associated transformation strain, as well as the influence of Si and Mn were investigated. The coefficients of linear thermal expansion for both the bulk materials and individual phases are also obtained. The results indicate that an increase in the Mn and Si contents show little influence on the onset of retained austenite decomposition, but result in more thermally stable austenite. The decomposition is accompanied by a simultaneous increase in ferrite content which causes an expansive strain in the order of 10 − 4 , and subsequent cementite development from 300 to 350 °C which causes a contraction that helps to neutralise the expansive strain. During decomposition, a continuous increase in the carbon content of austenite, and a reduction in that of the tempered-martensite/ferrite phase was observed. This process continued at elevated temperatures until full decomposition was reached, which could take less than an hour at a heating rate of 0.05 ° C /s. Additionally, the observation of austenite peak splitting on samples with high Mn and Si contents suggests the existence of austenite of different stabilities in such matrix.
Veena Sahajwalla - One of the best experts on this subject based on the ideXlab platform.
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Effect of austenitisation temperature on corrosion resistance properties of dual-phase High-Carbon steel
Journal of Materials Science, 2019Co-Authors: Wilson Handoko, Farshid Pahlevani, Veena SahajwallaAbstract:Austenitisation is one of the most important factors in heat treatment process of dual-phase High-Carbon steel, as it can affect the grain size, production of secondary phase precipitation, size of martensite laths and distribution of the phases. Despite the importance of this heat treatment on mechanical behaviour, its correlation on corrosion behaviour and electrochemical properties of High-Carbon steel required in-depth investigation. The aim of this study is to investigate the effect of different austenitising temperatures on microstructure and corrosion behaviour of dual-phase High-Carbon steel. Microstructural evolution was observed in situ using ultra-high-temperature laser microscope, and the Steels have been characterised further using optical microscope, electron backscatter diffraction, 3D laser scanning confocal microscope, scanning electron microscope and energy energy-dispersive spectroscope and electron probe microanalysis. The powerful electrochemical corrosion test was employed by using Tafel polarisation method to measure its corrosion rate. Results have indicated that higher austenitising temperature increased grain size of retained austenite and martensite, which reduced the grain boundary length, but at the same time increased the size and amount of carbide precipitations. As the main corrosion mechanisms in dual-phase High-Carbon steel were pitting corrosion and intergranular corrosion, effect of generated precipitations has overcome grain boundary corrosion caused by influence of size and shape of microstructures and, thus, reduced the corrosion resistance around 9.68% as temperature increased. These findings are crucial for designing new applications from High-Carbon Steels for mining and automotive industries.
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effect of small addition of cr on stability of retained austenite in high carbon steel
Materials Characterization, 2017Co-Authors: Rumana Hossain, Farshid Pahlevani, Veena SahajwallaAbstract:Abstract High carbon Steels with dual phase structures of martensite and austenite have considerable potential for industrial application in high abrasion environments due to their hardness, strength and relatively low cost. To design cost effective high carbon Steels with superior properties, it is crucial to identify the effect of Chromium (Cr) on the stability of retained austenite (RA) and to fully understand its effect on solid-state phase transition. This study addresses this important knowledge gap. Using standard compression tests on bulk material, quantitative X-ray diffraction analysis, nano-indentation on individual austenitic grains, transmission electron microscopy and electron backscatter diffraction–based orientation microscopy techniques, the authors investigated the effect of Cr on the microstructure, transformation behaviour and mechanical stability of retained austenite in high carbon steel, with varying Cr contents. The results revealed that increasing the Cr %, altered the morphology of the RA and increased its stability, consequently, increasing the critical pressure for martensitic transformation. This study has critically addressed the elastoplastic behaviour of retained austenite – and provides a deep understanding of the effect of small additions of Cr on the metastable austenite of high carbon steel from the macro- to nano-level. Consequently, it paves the way for new applications for high carbon low alloy Steels.
Veronique Smanio - One of the best experts on this subject based on the ideXlab platform.
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low temperature kinetics of bainite formation in high carbon Steels
Acta Materialia, 2013Co-Authors: Thomas Sourmail, Veronique SmanioAbstract:Abstract This work is concerned with quantifying and discussing the influence of alloying elements on the kinetics of bainite formation at low temperatures (220–250 °C) in high carbon, high silicon Steels (100Cr6 and similar grades). In a first step, it is shown that the austenite carbon content is strongly influenced not only by the austenitizing temperature, but also by its duration. A method is thus proposed and validated to estimate this content and ensure that later comparisons are meaningful. In a second step, the influence of Cr, Mn, Mo and Si are evaluated. The relative effects of C, Mn, Cr and Mo are shown to be quantitatively in reasonable agreement with calculated driving forces, with C being by far the strongest retardant of bainite formation. The influences of Mn and Cr are found to be of similar order of magnitude, though with a stronger influence of Mn. Si is shown to continuously slow down bainite kinetics with increasing content, with no threshold content identified and an influence that is stronger than that of Mn or Cr. The role of Si is discussed and the current accepted mechanism is shown to be inconsistent with present and published observations. A new possibility is discussed for how Si influences kinetics in the investigated conditions (carbon content, temperature).
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tensile behaviour of a nanocrystalline bainitic steel containing 3 wt silicon
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: C Garciamateo, Thomas Sourmail, Veronique Smanio, F G Caballero, Matthias Kuntz, J Cornide, Roberto ElviraAbstract:Abstract Much recent work has been devoted to characterize the microstructure and mechanical properties bainitic nanostructured Steels. The microstructure is developed by isothermal heat treatment at temperatures as low as 125–350 °C and adapted steel grades typically contain high carbon contents to achieve sufficient depletion of the B S – M S temperature range, and above 1.5 Si wt.% to suppress carbide formation during isothermal holding. On the latter, most of the published literature agrees on a limit of around 1.2–1.5 wt.% to suppress cementite in high carbon Steels. For this reason perhaps, additions of Si significantly above this limit have not been investigated systematically in the context of nanostructured bainitic Steels. The present work is concerned with the effect of up to ∼3 Si wt.% in a steel grade adapted to low temperature bainitizing. Tensile properties as compared to similar grades, though with lower Si contents, exhibited unrivalled combinations of strength and ductility, with above 21% total elongation for a UTS above 2 GPa. An attempt is made to explain the mechanical properties of this microstructure in terms of some of its most relevant and unique morphological and microstructural features.
Hong Liang - One of the best experts on this subject based on the ideXlab platform.
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low temperature boriding of high carbon steel
Surface & Coatings Technology, 2015Co-Authors: Huaping Xiao, Fevzi M Ozaydin, K Balzuweit, Hong LiangAbstract:Abstract Boriding has attracted great interests in improving mechanical performance of materials. The high processing temperature and the relatively thin boride layer, however, have limited its applications. Here we report a method to boronize High-Carbon Steels at a relatively low temperature (780 °C). Using the arc melting process, a thick (> 400 μm) boronized coating is obtained. Two iron-boride phases (FeB and Fe2B) coexist in the borided layer. The surface hardness of the steel is increased by ~ 57%, while the friction is reduced by ~ 17% and ~ 65% under steel-steel and steel-diamond contacts, respectively. In a 40,000 cycle wear test, the wear track on the steel surface becomes invisible after the boriding treatment. The low-temperature process developed in this study is applicable to other materials and is effective in making thick boride coatings with less energy consumption.