Atrito interno em aços inoxidáveis austeníticos contendo cobre

Simões, Maurício Silva; Castro, Ana Luiza Resende de; Andrade, Margareth Spangler

doi:10.1590/s0370-44672010000100009

Cited by 3 publications

(2 citation statements)

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“…Previous dilatometric studies revealed e fi c reverse transformation between RT and 473 K (200°C) and a¢ fi c reverse transformation in the range of 773 K to 1073 K (500°C to 800°C). [3,20] Both (e fi c, a¢ fi c) transformations are shifted to higher temperatures with the increase of heating rate (at the heating rate higher than 0.1 K/s). [21] Tomimura et al described two types of possible reverse transformation (a¢ fi c) mechanisms: 1st diffusive by nucleation and growth of new austenite grains and 2nd diffusionless shear reversion.…”

Section: Introductionmentioning

confidence: 99%

The Investigation of Strain-Induced Martensite Reverse Transformation in AISI 304 Austenitic Stainless Steel

Cios

Tokarski

Żywczak

et al. 2017

Metall Mater Trans A

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This paper presents a comprehensive study on the strain-induced martensitic transformation and reversion transformation of the strain-induced martensite in AISI 304 stainless steel using a number of complementary techniques such as dilatometry, calorimetry, magnetometry, and in-situ X-ray diffraction, coupled with high-resolution microstructural transmission Kikuchi diffraction analysis. Tensile deformation was applied at temperatures between room temperature and 213 K (À60°C) in order to obtain a different volume fraction of strain-induced martensite (up to~70 pct). The volume fraction of the strain-induced martensite, measured by the magnetometric method, was correlated with the total elongation, hardness, and linear thermal expansion coefficient. The thermal expansion coefficient, as well as the hardness of the strain-induced martensitic phase was evaluated. The in-situ thermal treatment experiments showed unusual changes in the kinetics of the reverse transformation (a¢ fi c). The X-ray diffraction analysis revealed that the reverse transformation may be stress assisted-strains inherited from the martensitic transformation may increase its kinetics at the lower annealing temperature range. More importantly, the transmission Kikuchi diffraction measurements showed that the reverse transformation of the strain-induced martensite proceeds through a displacive, diffusionless mechanism, maintaining the Kurdjumov-Sachs crystallographic relationship between the martensite and the reverted austenite. This finding is in contradiction to the results reported by other researchers for a similar alloy composition.

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Section: Introductionmentioning

confidence: 99%

The Investigation of Strain-Induced Martensite Reverse Transformation in AISI 304 Austenitic Stainless Steel

Cios

Tokarski

Żywczak

et al. 2017

Metall Mater Trans A

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“…Resultados semelhantes observados para aços inoxidáveis do tipo 304. (8,9) No aço 304N não foi possível distinguir um terceiro pico em 140°C. Este pico, no entanto, torna-se visível por meio da decomposição da curva de atrito interno em seus componentes básicos (Figura 8b).…”

Section: ε α'unclassified

Atrito Interno Em Aços Inoxidáveis Austeníticos Abnt 304

Machado,

Castro,

Andrade

2009

ABM Proceedings

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ResumoEste trabalho teve por objetivo estudar o comportamento do amortecimento de vibrações mecânicas em um aço inoxidável austenítico tipo ABNT 304 com adição de cobre. Ensaios de tração foram realizados em corpos de prova do aço em temperaturas no intervalo de -50°C a 20ºC e quantidades de deformação verdadeira de 3% a 12%, com a finalidade de se obterem diferentes quantidades de fases martensíticas dos tipos de ε e α'. As martensitas induzidas foram investigadas por meio de ensaios de atrito interno em um pêndulo de torção invertido na faixa de temperatura de 40 a 400ºC. Ensaios dilatométricos foram realizados para apoiar a interpretação de resultados. Os ensaios de atrito interno revelaram a presença de martensita ε em quantidades crescentes com a deformação e para temperatura mais baixas. A influência de ε no atrito interno do aço ficou bem estabelecida pela ocorrência de um pico nas temperaturas de reversão desta martensita em torno de 100°C. A presença de α' foi associada a picos de atrito interno em torno de 140°C e 320ºC em amostras deformadas nas temperaturas de -30°C e -50ºC. Nas temperaturas de -10 e 20ºC, praticamente não foi observada ocorrência de α'. Palavras-chave: Aços inoxidáveis austeníticos; Dilatometria; Atrito interno.

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The Effect of Reversion of Strain-Induced Martensite (SIM) and Grain Refinement on the Intergranular Corrosion of High Mn Steel

2021

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The surface phase constituent of high-manganese austenitic stainless steel after cold work (15%, 30%, and 50%) and thermal aging at 900°C for 30 min. and 6 hrs, was characterized using X-Ray diffraction spectrum. The microstructural analysis was conducted using an optical microscope, a scanning electron microscope, and the electron back scattered diffraction technique. The double-loop electrochemical potentiokinetic reactivation test was used to measure the Intergranular corrosion resistance (degrees of sensitization). The results showed that fine-recovered grains of austenite and strain-induced martensite together formed the surface of high-manganese steel after cold work. Because of the formation of strain-induced martensite in the cold work samples, their Intergranular corrosion were much higher than that of the as-received sample. Besides, the degree of sensitization of 15% cold work was higher (i.e., more intergranular corrosion) compared to the degrees of sensitization of 30% and 50% cold work. On the contrary, the intergranular corrosion of high-manganese austenitic stainless steel sample subjected to cold work was eliminated during thermal aging at 900°C for six hours because of the reversion of strain-induced martensite and fine-reverted austenite grains. Owing to this grain refinement of austenite, faster diffusion rate of Cr at higher temperature and cold work helped healing of Cr-depletion zone in a shorter time. In other words, because the results showed that on 50% cold work and thermal aging at 900°C for six hours, the high-manganese austenitic stainless steel does not become susceptible to intergranular corrosion. Hence, it could be beneficial to investigate the intergranular corrosion of high-manganese austenitic stainless steel.

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Atrito interno em aços inoxidáveis austeníticos contendo cobre

Cited by 3 publications

References 3 publications

The Investigation of Strain-Induced Martensite Reverse Transformation in AISI 304 Austenitic Stainless Steel

The Investigation of Strain-Induced Martensite Reverse Transformation in AISI 304 Austenitic Stainless Steel

Atrito Interno Em Aços Inoxidáveis Austeníticos Abnt 304

The Effect of Reversion of Strain-Induced Martensite (SIM) and Grain Refinement on the Intergranular Corrosion of High Mn Steel

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