Phase transformation and mechanical behavior in annealed 2205 duplex stainless steel welds

Badji, Riad; Bouabdallah, M.; Bacroix, Brigitte; Kahloun, C.; Belkessa, Brahim; Maza, H.

doi:10.1016/j.matchar.2007.03.004

Cited by 227 publications

(127 citation statements)

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“…In most of these applications welding is used to join the parts, being then a crucial process in the fabrication involving LDX steels [7]. Among these steels, the most common one is the UNS S32304, table 1 [7,8] Changes in microstructure of duplex stainless steels during fabrication depends on the characteristics of the processing used (welding, cold working, heat treatments, etc.) and their variations and may have a significant impact on the final microstructure.…”

Section: Introductionmentioning

confidence: 99%

“…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%

“…Similar transformations occur in the fusion zone particularly when its composition is similar to that of the base metal. Consequently, the microstructure of these regions do not have the same balance of ferrite and austenite as the base material and tend to present a much lower amount of austenite [8]. Mechanical properties, particularly toughness, may deteriorate by the new phase fraction balance.…”

Section: Introductionmentioning

confidence: 99%

“…For lower peak temperatures, between T1 and T2 (Figure 1), the amount of austenite can still decrease. However, at these peak temperatures, a two-phase microstructure is maintained, grain growth tends to be minimal and the microstructure is quite similar to that of the base metal [5][6][7][8][9][10]. At regions that were heated to temperatures lower than 1000 °C, particularly those that are submitted to multiple thermal cycles (multipass welding), the contents of Cr and Mo of the of the higher alloyed duplex stainless steels can lead to the formation of different intermetallic compounds, especially the so-called sigma () and chi () phases.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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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.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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“…2016;21(2):165-171 conductivity and have a lower thermal expansion coefficient than austenitic steels. Further, the duplex structure assures considerably high strength levels at elevated temperature, good toughness and ductility [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Detrimental Cr-rich Phases Precipitation on SAF 2205 Duplex Stainless Steels Welds After Heat Treatment

Pérez¹,

Breda

Calliari

et al. 2016

Soldag. insp.

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Abstract:The austeno-ferritic Stainless Steels are commonly employed in various applications requiring structural performances with enhanced corrosion resistance. Their characteristics can be worsened if the material is exposed to thermal cycles, since the high-temperature decomposition of ferrite causes the formation of detrimental secondary phases. The Submerged Arc Welding (SAW) process is currently adopted for joining DSS owing to its relatively simple execution, cost savings, and using molten slag and granular flux from protecting the seam of atmospheric gases. However, since it produces high contents of δ-ferrite in the heat affected zone and low content of γ-austenite in the weld, high-Ni filler materials must be employed, to avoid excessive ferritization of the joint. The present work is aimed to study the effect of 3 and 6 hours isothermal heat treatments at 850°C and 900°C in a SAF 2205 DSS welded joint in terms of phases precipitation. The results showed the presence of σ-phase at any time-temperature combination, precipitating at the δ/γ interphases and often accompanied by the presence of χ-phase. However, certain differences in secondary phases amounts were revealed among the different zones constituting the joint, ascribable both to peculiar elements partitioning and to the different morphology pertaining to each microstructure. Key-words:Duplex Stainless Steels; SAW; Heat treatment; Sigma; Chi. Precipitação de Fases Prejudiciais Ricas em Cromo em Soldas de Aço Inoxidável Duplex SAF 2205 Após Tratamento TérmicoResumo: Os Aços Inoxidáveis austeno-ferriticos são comumente utilizados em diversas aplicações que requerem desempenho estrutural, maior resistência à corrosão. As suas características podem ser prejudicadas se o material for exposto a ciclos térmicos, uma vez que a decomposição a alta temperatura da ferrita provoca a formação de fases secundárias prejudiciais. O processo de soldagem a arco submerso (SAW) é atualmente adotado para unir DSS devido à sua execução relativamente simples, economia de custos, e utiliza escória fundida e fluxo granular para proteger a costura dos gases atmosféricos. No entanto, uma vez que são produzidos elevados teores de ferrita-δ na zona afetada pelo calor e baixo teor de austenita-γ na solda, materiais de adição de alto-Ni devem ser empregados, de modo a evitar excessiva ferritização na junta. O presente trabalho tem como objetivo estudar o efeito de 3 e 6 horas de tratamentos térmicos isotérmicos a 850°C e 900°C em uma junta soldada de DSS SAF 2205 em termos de precipitação de fases. Os resultados mostraram a presença de fase-σ em qualquer combinação de tempo-temperatura, precipitando nas interfases δ/γ e muitas vezes acompanhada pela presença de fase-χ. No entanto, algumas diferenças na quantidade de fases secundárias foram reveladas nas diferentes zonas que constituem a junta, ambas atribuídas aos elementos peculiares de partição e à morfologia diferente pertencente a cada microestrutura. Palavras-chave:Aços inoxidáveis duplex; SAW; Tratamento térmico; Sigma...

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The Effect of Cooling Intensity on the Solidification Structure and Ferrite Phase Fraction of a Duplex Stainless Steel

Zhang

et al. 2014

EPD Congress 2014

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Phase transformation and mechanical behavior in annealed 2205 duplex stainless steel welds

Cited by 227 publications

References 11 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

Detrimental Cr-rich Phases Precipitation on SAF 2205 Duplex Stainless Steels Welds After Heat Treatment

The Effect of Cooling Intensity on the Solidification Structure and Ferrite Phase Fraction of a Duplex Stainless Steel

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