Ageing of forged superaustenitic stainless steel: Precipitate phases and mechanical properties

Anburaj, J.; Nazirudeen, S.S. Mohamed; Narayanan, R.; Anandavel, B.; Chandrasekar, A.

doi:10.1016/j.msea.2011.12.048

Cited by 73 publications

(34 citation statements)

References 30 publications

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“…The U T values are calculated by the total area under the stress-strain curve and should not be confused or compared to the impact of toughness values, which have been measured in previous studies [38,39], because it includes not only the energy absorbed during fracture but also the energy absorbed during plastic deformation. The evolution of U T versus ageing time and temperature (Fig.…”

Section: Correlation Of Precipitation With Mechanical Behaviormentioning

confidence: 99%

Phase transformations and mechanical properties in heat treated superaustenitic stainless steels

Koutsoukis

Redjaïmia

Fourlaris

2013

Materials Science and Engineering: A

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Section: Correlation Of Precipitation With Mechanical Behaviormentioning

confidence: 99%

Phase transformations and mechanical properties in heat treated superaustenitic stainless steels

Koutsoukis

Redjaïmia

Fourlaris

2013

Materials Science and Engineering: A

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“…Carbides of the kind M 23 C 6 and M 6 C are formed due to the high presence of carbon, and the most common intermetallic phases are: sigma phase (), Laves and Chi phase () [3], [4], many times studied from TTT diagrams. Several works in the literature aimed to investigate the presence of such phases and their effects [5], [6], [7]. This study presents a set of complementary data to the research started at Unicamp [8], [9], [10] coordinated by Prof. Dr. Paulo R. Mei and collaborators in the ASTMA 744 Gr.…”

Section: Introductionmentioning

confidence: 99%

Mechanical, structural and tribological properties of superaustenitic stainless steel submitted at solution heat treatment

Borges¹,

Oliveira²,

Kublitski³

2015

Matéria (Rio J.)

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RESUMOO aço inoxidável superasutenítico apresenta diversas aplicações tecnológicas, principalmente em ambientes corrosivos. A precipitação de diferentes fases pode alterar algumas de suas propriedades mecânicas. Tais alterações afetam vários fatores, incluindo a vida útil do material diante de condições de trabalho adversas. Neste estudo, medidas de Indentação Instrumentada, Tribologia e Difração de Raios X (DRX) foram utilizadas para avaliar possíveis alterações em regiões próximas à superfície em amostras tratadas termicamente. Os parâmetros analisados foram: dureza e módulo de elasticidade, coeficiente de atrito e alterações estruturais na célula unitária nas fases identificadas. Os resultados foram comparados com aço austenítico comum da famí-lia AISI 304. A presença das fases  (grupo espacial P42mnm) e austenita- (grupo espacial Fm3m) foram detectadas. Os dados analisados indicaram que a presença da fase intermetálica  contribuiu para pequenas alterações na dureza em regiões próximas à superfície e no coeficiente de atrito. Para regiões mais profundas (bulk) as propriedades analisadas foram semelhantes aos aços inoxidáveis comerciais.Palavras-chave: aço austenítico, aço superaustenitico, refinamento Rietveld. ABSTRACTThe superaustenitic stainless steel presents several technological applications, mainly in corrosive environments. The different phase precipitation might alter some of its mechanical properties. Such alterations affect several factors, including the working life of the material under adverse working conditions. In this study, Instrumented Indentation techniques, Tribology and X-ray diffraction (XRD) were used to evaluate alterations in regions close to the surface. The parameters analyzed were: hardness and elastic modulus (instrumented indentation), friction coefficient (tribology) and structural alterations of the unit cell of the identified phases (XRD -Rietveld Refinement). All properties analyzed were compared with those of common austenitic steel. The presence of -phase (space group P42mnm) and -austenite (space group Fm3m) were detected. Data analyzed indicated that the presence of -phase caused small alteration in properties such as hardness in regions close to the surface. In the regions farther from the surface (material bulk) data can be compared to that of conventional austenitic steel.

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“…While intergranular fracture is quite common after long-term annealing [1,4,13] due to precipitation it is unusual to occur so quickly after short times, and the size scale of the precipitates is too small to investigate using SEM. Additionally, the observance of transgranular fracture after short annealing times is relatively new for SSSs.…”

Section: Resultsmentioning

confidence: 99%

“…A common index known as pitting resistance equivalent number (PREN 30 ) is commonly used in stainless steels to give a quantitative measure of pitting corrosion resistance. The empirical formula representing PREN 30 is given as [1] :…”

Section: Mertcan Başkan Scott L Chumbley and Yunus Eren Kalaymentioning

confidence: 99%

“…Off-shore oil wells, seawater handling, chemical and food processing equipment in addition to heat exchangers and piping in purification systems are the application areas of SSS. [2] Equation [1] clearly shows that pitting resistance can be enhanced by increasing the amount of chromium and molybdenum. However, when superaustenitic steels are exposed to high temperatures, such as 823 K to 1223 K (550°C to 950°C), the formation of intermetallic phases is almost inevitable due to the high alloying content.…”

Section: Mertcan Başkan Scott L Chumbley and Yunus Eren Kalaymentioning

confidence: 99%

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Embrittlement in CN3MN Grade Superaustenitic Stainless Steels

Baskan

Chumbley

Kalay

2014

Metall Mater Trans A

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Superaustenitic stainless steels (SSS) are widely used in extreme environments such as off-shore oil wells, chemical and food processing equipment, and seawater systems due to their excellent corrosion resistance and superior toughness. The design of the corresponding heat treatment process is crucial to create better mechanical properties. In this respect, the short-term annealing behavior of CN3MN grade SSS was investigated by a combined study of Charpy impact tests, hardness measurements, scanning and transmission electron microscopy. Specimens were heat treated at 1200 K (927 °C) for up to 16 minutes annealing time and their impact strengths and hardnesses were tested. The impact toughness was found to decrease to less than the half of the initial values while hardness stayed the same. Detailed fracture surface analyses revealed a ductile to brittle failure transition for relatively short annealing times. Brittle fracture occurred in both intergranular and transgranular modes. SEM and TEM indicated precipitation of nano-sized intermetallics, accounting for the intergranular embrittlement, along the grain boundaries with respect to annealing time. The transgranular fracture originated from linear defects seen to exist within the grains. Close observation of such defects revealed stacking-fault type imperfections, which lead to step-like cracking observed in microlength scales. Superaustenitic stainless steels (SSS) are widely used in extreme environments such as off-shore oil wells, chemical and food processing equipment, and seawater systems due to their excellent corrosion resistance and superior toughness. The design of the corresponding heat treatment process is crucial to create better mechanical properties. In this respect, the short-term annealing behavior of CN3MN grade SSS was investigated by a combined study of Charpy impact tests, hardness measurements, scanning and transmission electron microscopy. Specimens were heat treated at 1200 K (927°C) for up to 16 minutes annealing time and their impact strengths and hardnesses were tested. The impact toughness was found to decrease to less than the half of the initial values while hardness stayed the same. Detailed fracture surface analyses revealed a ductile to brittle failure transition for relatively short annealing times. Brittle fracture occurred in both intergranular and transgranular modes. SEM and TEM indicated precipitation of nanosized intermetallics, accounting for the intergranular embrittlement, along the grain boundaries with respect to annealing time. The transgranular fracture originated from linear defects seen to exist within the grains. Close observation of such defects revealed stacking-fault type imperfections, which lead to step-like cracking observed in microlength scales. Keywords Surfaces and Interfaces, Thin Films Nanotechnology

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Ageing of forged superaustenitic stainless steel: Precipitate phases and mechanical properties

Cited by 73 publications

References 30 publications

Phase transformations and mechanical properties in heat treated superaustenitic stainless steels

Phase transformations and mechanical properties in heat treated superaustenitic stainless steels

Mechanical, structural and tribological properties of superaustenitic stainless steel submitted at solution heat treatment

Embrittlement in CN3MN Grade Superaustenitic Stainless Steels

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