Avaliação da proporção de fases em juntas soldadas de tubulações de aço inoxidável duplex mediante aplicação de ensaios não destrutivos

Souza, Guttemberg Chagas de; Pardal, Juan Manuel; Tavares, Sérgio Souto Maior; Fonseca, Maria Cindra; Martins, José Luiz; Moura, Elineudo Pinho de; Filho, Ismael Cardote

doi:10.1590/s0104-92242013000200009

Cited by 8 publications

(5 citation statements)

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“…34,35 Unfortunately, this technique has disadvantages, such as the need of a professional with high training and qualification, demanding a high time of preparation, execution and taking into account a limit of detection higher than conventional metallography. 36 An alternative, not yet mentioned, is the use of electrochemical techniques (e.g. Electrochemical Impedance Spectroscopy (EIS), Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR)).…”

mentioning

confidence: 99%

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Sampaio

Furtado

Tavares

et al. 2020

J. Electrochem. Soc.

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Linear sweep voltammetry (LSV) test parameters in alkaline medium were optimized by Doehlert matrix design in order to quantify the deleterious phases in a superduplex stainless steel UNS S32750. The microstructural analysis was performed, in several heat treated specimens, by Light Optical (LOM) and Scanning Electron (SEM) Microscopies and correlated with the electrochemical tests. In these tests, optimized parameters were obtained for tests in aqueous solutions of KOH. The concentration of 3.55 mol l −1 , scan rate of 3.42 mV s −1 and initial potential of −0.818 V, showed a good correlation between the deleterious phases precipitated and charge density values. Differently from LOM characterization, chi and sigma deleterious phases can be distinguished by LSV optimized test. Finally, this test can be a non-destructive powerful tool of quality control to detect embrittlement and corrosion resistance decay that commonly affected this stainless steel as consequence of inadequate fabrication processes.

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mentioning

confidence: 99%

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Sampaio

Furtado

Tavares

et al. 2020

J. Electrochem. Soc.

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“…This technique provides quick information about the amount of the ferritic phase, due to its magnetic property, being a technique using a portable equipment, easy to operate and non-destructive. However, it is not suitable for small areas and doesn't guarantee an exact quantification of ferrite as the processing of the analyzed steel can influence the result, since the size, shape and orientation of the resulting ferrite can significantly modify the magnetic response of this phase [6], [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Methods Analysis for Phase Measurement in Welded Sample of Superduplex Stainless Steel Uns S32750

Júnior¹,

Silvaa²,

Seixas³

et al. 2020

Blucher Engineering Proceedings

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This study presents an evaluation of two methods to measure phases in welded samples of super duplex stainless steel UNS S32750. The aim is to identify the most suitable method for characterizing the microstructure of welded joints of this steel. In the color contrast method, it was found that there was no great variation in the results due to the low value of the standard deviation. While for the ASTM E 652 standard point counting method, the percentage values of ferrite found were slightly higher than the previous method. However, these two methods produced low standard deviations and, since the method described by the standard is possible to differentiate deleterious phases, this technique is the most suitable for the microstructure characterization for welded samples of super duplex stainless steel.

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“…Dentre esses aços AILD, o mais comumente utilizado é o UNS S32304. Diversas aplicações dos AILD foram reportadas na literatura [2], tais como, em tanques de estocagem na indústria de papel e celulose,na indústria offshoree também em tanques de armazenamento de alimentos. Os aços inoxidáveis duplex têm sido recentemente atraídos pelo grande interesse devido a sua combinação de economia de custos e propriedades desejadas para este aço tais como alta resistência mecânica, à corrosão localizada, à abrasão e ao desgaste.…”

Section: Introductionunclassified

Análise Microestrutural De Um Aço Inoxidável Duplex Uns S32304 Submetido Ao Processo De Soldagem Gmaw

Grilo¹,

Siqueira²,

Arruda³

et al. 2017

Anais Do Congresso Anual Da ABM

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ResumoO presente trabalho teve como objetivo analisar as diferentes microestruturas do aço inoxidável duplex UNS S32304 obtidas pelo processo de soldagem Gas Metal Arc Welding (GMAW). As regiões do metal base, zona fundida e zona afetada pelo calor foram investigadas nos corpos de prova com diferentes aportes térmicos. As microestruturas obtidas foram caracterizadas utilizando-se a microscopia óptica (MO). As imagens de Mo obtidas na zona afetada pelo calor mostram que a fração de austenita aumentou com o aumento do aporte térmico. Este aumento está relacionado ao alto teor de cromo e molibdênio presentes no metal de adição utilizado na soldagem. Na zona fundida, a fração de austenita de widmansttaten foi observada com maior frequência na microestrutura do corpo de prova soldado com o aporte térmico de 1,87KJ/mm. Essa maior fração de austenita de widmansttaten observada para o aporte térmico de 1,87KJ/mm está relacionada com o maior tempo de permanência em altas temperaturas deste corpo de prova em relação aos outros corpos de prova investigados. Vale ressaltar que a adição de nitrogênio também promove a formação desta fase. De modo geral, os resultados da metalografia quantitativa mostram que a porcentagem de ferrita foi superior a 65% nas zonas termicamente afetadas e fundidas. Palavras-chave: Aços inoxidáveis duplex; Soldagem; GMAW; Fase sigma; Microestrutura. MICROSTRUCTURAL ANALYSIS OF A DUPLEX STAINLESS STEEL UNS S32304SUBMITTED TO GMAW WELDING PROCESS. Abstract The microstructures of the duplex stainless steel obtained by the Gas Metal Arc Welding (GMAW) were evaluated. The base metal, fusion zone and the heat-affected zone were investigated in the samples with different heat inputs. The microstructures were characterized using light microscopy (LM). The LM images obtained in the heat-affected zone shows that the austenite volume fraction increased with the heat input increase. This increase is related to high contents of the chromium and molybdenum present in the filler metal used in welding. The fusion zone, the widmansttaten austenite volume fraction was observed more frequently in the microstructure with heat input of 1,87KJ/mm. This higher widmansttaten austenite volume fraction with the heat input of 1,87KJ/mm is related to the higher cooling time at high temperatures in this sample in relationship to the others investigated samples. It is noteworthy that the addition of nitrogen also promotes this phase. In general, the results of the quantitative metallography showed that the percentage of ferrite was greater than 65% in the heataffected and fusion zones. Keywords: UNS 32304; Welding microstructure; GMAW; Sigma-phase; Microestruture. UFF, Volta Redonda, RJ, Brasil. 3 Graduando em engenharia metalúrgica, UFF, Volta Redonda, RJ, Brasil. 731

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Avaliação da proporção de fases em juntas soldadas de tubulações de aço inoxidável duplex mediante aplicação de ensaios não destrutivos

Abstract: Resumo Os aços inoxidáveis Duplex (AID) aliam uma excelente resistência à corrosão com elevada resistência mecânica devido à fina microestrutura bifásica composta por quantidades similares de ferrita (d) e austenita (g).

Cited by 8 publications

References 5 publications

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Sigma and Chi Phases Analysis in UNS S32750 Superduplex Stainless Steel by Optimized Linear Sweep Voltammetry in Alkaline Medium

Methods Analysis for Phase Measurement in Welded Sample of Superduplex Stainless Steel Uns S32750

Análise Microestrutural De Um Aço Inoxidável Duplex Uns S32304 Submetido Ao Processo De Soldagem Gmaw

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