Sigma Phase
Mostrando 1-12 de 328 artigos, teses e dissertações.
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1. Resistência à Corrosão de Juntas Dissimilares dos Aços AISI 316L e da Liga Inconel 718
Resumo A soldagem dissimilar (Dissimilar Metal Welds – DMWs), união de dois diferentes materiais metálicos, tem muitas aplicações industriais, com destaque para trocadores de calor nas usinas nucleares. Portanto, devem resistir à corrosão e a esforços mecânicos, entre outros requisitos. Neste trabalho foi abordada a susceptibilidade à corrosão d
Soldag. insp.. Publicado em: 21/10/2019
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2. Effect of Sigma Phase Precipitated at 850 °C on Corrosion Behaviour of UNS S82441 Duplex Stainless Steel
ABSTRACT Duplex stainless steels (DSS) are alloys with binary microstructure consisting of ferrite (δ) and austenite (γ), combining high mechanical properties and corrosion resistance by pitting and stress corrosion, due to the two phases austenite/ferrite. However, the formation of secondary and intermetallic phases, during solidification processes, heat
Matéria (Rio J.). Publicado em: 16/09/2019
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3. Avaliação da susceptibilidade de precipitação da fase sigma na soldagem do aço inoxidável duplex SAF2205
RESUMO A soldagem de aços inoxidáveis duplex é uma operação crítica, devido aos ciclos térmicos aos quais o material é submetido, que podem favorecer a precipitação de fases deletérias. Nesse contexto, objetivo dessa pesquisa é analisar a influência da energia de soldagem na susceptibilidade à formação de fase sigma no aço duplex SAF2205. As
Matéria (Rio J.). Publicado em: 16/09/2019
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4. Influence of the Solution-Treatment Temperature and Short Aging Times on The Electrochemical Corrosion Behaviour of Uns S32520 Super Duplex Stainless Steel
Sigma phase leads to deterioration of corrosion resistance of super duplex stainless steels (SDSS) and its volume fraction increases as the time which the materials is exposed in determined temperature increases. In the present study, the effect of the short aging time on the formation of the sigma phase and on the corrosion behavior of UNS S32520 SDSS at 3.
Mat. Res.. Publicado em: 15/08/2019
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5. A New methodology of Nondestructive Testing for Quantitative Evaluation of Sigma Phase in Duplex Stainless Steels
Duplex Stainless Steels (DSSs) are widely used in the oil and gas industry. When the steel is subjected to a thermal gradient, as in welding may occur precipitation of intermetallic phases. Among these phases, there is the sigma phase, which even in small quantities reduces drastically the mechanical and corrosion resistance properties. According to some stu
Mat. Res.. Publicado em: 13/05/2019
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6. Double Kinetics of Intermetallic Phase Precipitation in UNS S32205 Duplex Stainless Steels Submitted to Isothermal Heat Treatment
One of the most studied deleterious phases in stainless steels is the sigma phase, due to its high potential to decrease the toughness and corrosion resistance of these steels. Eight samples of as-received cold rolled UNS S32205 duplex stainless steel were submitted to isothermal heat treatments at 850 oC during 10, 15, 30, 60, 120, 180, 240, and 300 minutes
Mat. Res.. Publicado em: 26/06/2017
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7. Microstructural Transformation in a Root Pass of Superduplex Stainless Steel Multipass Welding
The microstructure of the root pass in a superduplex stainless steel multipass welding was investigated.Results showed that the welding metal has an austenite matrix with particles of sigma phase formed in the ferrite/austenite interface and intragranularly.Eventhough the filler metal is intended to keep the phase balance after welding,the welding metal pres
Mat. Res.. Publicado em: 06/02/2017
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8. Sigma Phase in Superduplex Stainless Steel: Formation, Kinetics and Microstructural Path
The superduplex stainless steels (SDSS) are widely used in chemical, oil and gas industries, to pipelines and storage material facilities. In welding process or working in temperature elevated, secondary phases may appear in the form of precipitates, as the sigma phase (σ) which is an intermetallic compound. This compound is harmful to the properties of ste
Mat. Res.. Publicado em: 09/01/2017
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9. Use of Magnetic Barkhausen Noise (MBN) to Follow Up the Formation of Sigma Phase in Saf2205 (UNS S31803) Duplex Stainless Steel
Abstract Duplex stainless steels have a structure normally composed of austenite and ferrite in approximately equal proportions. In order to attain control of its fabrication processes and performance, it is important to understand its microstructural evolution, due to the formation of intermetallic phases such as sigma (σ) and chi (χ), which may cause a s
Mat. Res.. Publicado em: 01/08/2016
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10. Effect of Cooling Rate on the Corrosion Behavior of As-Cast SAF 2205 Duplex Stainless Steel After Solution Annealing Treatment
The formation of intermetallic phases alters the properties of duplex stainless steel and is therefore a crucial factor in its performance. For example, the formation of sigma phase in duplex steel increases its brittleness and decreases its corrosion resistance because this phase consumes chromium and molybdenum in solid solution, thus leading to the deplet
Mat. Res.. Publicado em: 23/10/2015
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11. An Experimental and Numerical Approach for the Welding Effects on the Duplex Stainless Steel Microstructure
Key microstructural changes that occur when Duplex Stainless Steels (DSS) are welded could be evaluated when bead-on-plate welding was carried out on a 2205 DSS by the GMAW process. By using numerical simulations, it was possible to calculate locally the heating and cooling rates taking place during the 2205 DSS welding and discuss its correlation to the mic
Mat. Res.. Publicado em: 2015-06
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12. Effect of niobium in the phase transformation and corrosion resistance of one austenitic-ferritic stainless steel
Austenitic-ferritic stainless steels containing 0.2% and 0.5% niobium were evaluated with respect to the microstructures, microhardness, pitting potential resistance, electrochemical impedance and wearing tests. Niobium is an alphagenic element and has a great influence on phase transformation of duplex stainless steels. In the present investigation, the sam
Mat. Res.. Publicado em: 01/08/2014