Effects of thermal aging on microstructure and mechanical properties of duplex stainless steel weldments

Koussy, M. R. El; Mahallawi, I. S. El; Khalifa, Waleed; Dawood, M. M. Al; Bueckins, M.

doi:10.1179/174328413x13789824293821

Cited by 32 publications

(22 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…No evidence of precipitation of intermetallic phases or carbides was found on the weld metal. The same occurred at the reheated areas and at the HAZ for the studied specimens, even though this phenomenon has been frequently reported in literature for more alloyed duplex stainless steels [10,11,12].…”

Section: Optical Microscopy and Sem Resultsmentioning

confidence: 80%

“…In general, most of the weldability problems on duplex steels result from the reduction of the amount of austenite, particularly in fusion zone (FZ) and at the heat-affected zone (HAZ) and from the precipitation of nitrites and intermetallic compounds [8,11,12]. Due to their chemical composition, on heating duplex stainless steels completely transform to ferrite at around 1300-1400oC and maintain this structure up to their melting temperature.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure characterization of a duplex stainless steel weld by electron backscattering diffraction and orientation imaging microscopy techniques

et al. 2015

View full text Add to dashboard Cite

This paper describes the electron backscatter diffraction (EBSD) technique used to characterize the microstructure (especially the morphology and constitution) of the base metal (BM), the heat-affected zone (HAZ) and the fusion zone (FZ) on a lean duplex stainless steel (LDX). This technique provides advantages due to its simplicity of use and greater depth of information, thereby increasing the amount of information obtained by traditional characterization techniques such as optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The use of EBSD together with orientation imaging microscopy (OIM) as a tool to understand phase transformation paths and ferrite-austenite variant selection was discussed. Vickers microhardness measurements were performed and no significance difference between the different zones was found. Orientation distribution function (ODF) results show that there are no significant changes on the crystallographic texture of the samples after welding. The advantages of using SEM together with EBSD for microstructure analyzing and texture development were also discussed.

show abstract

Section: Optical Microscopy and Sem Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Microstructure characterization of a duplex stainless steel weld by electron backscattering diffraction and orientation imaging microscopy techniques

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Com o aumento do aporte térmico, a precipitação da fase austenita mais alongada com morfologia de widmansttaten foi ainda maior, como indicado por setas na micrografia da Figura 3. Esta fase pode ser nucleada tanto na interface entre grãos ferríticos e austeníticos como também pode ser formada a partir da austenita alotriomórfica formada no contorno de grão da ferrita [8,9]. Vale ressaltar que na zona fundida, o valor percentual da fase ferrita esteja na faixa de 35 a 65%, de modo a aliar boa resistência à corrosão e boas propriedades mecânicas [13].…”

Section: * Contribuição Técnica Ao 71º Congresso Anual Da Abm -Internunclassified

“…A soldabilidade dos aços inoxidáveis duplex é considerada inferior ao dos aços inoxidáveis austeníticos. Em geral a maior parte do problema da soldabilidade dos aços duplex resultam da redução da quantidade da austenita particularmente na zona fundida, na zona afetada pelo calor e precipitação de nitretos [7,8,9]. No presente trabalho teve por objetivo analisar e quantificar as fases presentes nas amostras soldadas via GMAW com o metal de adição OK Autrod 2509 com aporte térmico dentro da faixa especificada entre 0,5 e 2,5KJ/mm.…”

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

View full text Add to dashboard Cite

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

show abstract

“…Some of these applications depend on the capability to realize welded joints. However, phase transformations occur during welding in the molten zone (MZ) and in the heat affected zone (HAZ) with detrimental effects on the physical and mechanical properties of DSS [2], in particular the precipitation of secondary phases (SPs), like σ and χ, cause a serious reduction in toughness [3][4][5][6][7][8][9][10][11][12]. This generally derives from incorrect process parameters during either welding or post-welding heat treatments.…”

Section: Introductionmentioning

confidence: 99%

Flat-Top Cylinder Indenter Examination of Duplex Stainless Steel 2205 after Different Heat Treatments

Angella

Fava

Montanari

et al. 2017

Metals

View full text Add to dashboard Cite

Abstract:The duplex stainless steel 2205 was heat treated at 750 • C, 850 • C, and 900 • C for increasing durations of up to 10 h. The samples were investigated through light microscopy (LM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to characterize the volume fraction and morphology of the precipitated secondary phases. The samples were then tested via flat-top cylinder indenter for mechanical characterization (FIMEC) testing to determine the yield stresses that were found to be significantly affected by the different heat treatments. The yield stress evolution with heat treatments resulted in being correlated to both the relative volumes of the secondary phases and the morphology of the σ phase. The FIMEC test proved to be capable of detecting the effects of small amounts of secondary phases on yield stress in DSS 2205 and seems to be a promising technique for industrial applications.

show abstract

Effects of thermal aging on microstructure and mechanical properties of duplex stainless steel weldments

Cited by 32 publications

References 5 publications

Microstructure characterization of a duplex stainless steel weld by electron backscattering diffraction and orientation imaging microscopy techniques

Microstructure characterization of a duplex stainless steel weld by electron backscattering diffraction and orientation imaging microscopy techniques

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

Flat-Top Cylinder Indenter Examination of Duplex Stainless Steel 2205 after Different Heat Treatments

Contact Info

Product

Resources

About