Sensitization Of Aisi 409 Ferritic Stainless Steel During Low Heat Input Arc Welding

Niekerk, Cornelis Janise Van; Toit, Madeleine Du; Erwee, Markus Wouter

doi:10.1007/bf03321350

Cited by 22 publications

(20 citation statements)

References 6 publications

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“…Other authors studied that welding operations decreased the pitting corrosion resistance of the AISI 409 stainless steel but the investigation was focused on intergranular corrosion rather than on the pitting corrosion mechanism. Notwithstanding, the presence of titanium-rich precipitates was confirmed and the onset of localized attack was affected by the type of precipitates formed during heating and subsequent cooling from the welding temperature 13 . Although the reports mentioned above bring useful information regarding the pitting corrosion behavior of the AISI 409 stainless steel, a systematic approach correlating microstructural features with the stability of the passive film, localized corrosion mechanism and pitting morphology of this material is not found in the literature.…”

Section: Introductionmentioning

confidence: 96%

Electrochemical Study of the AISI 409 Ferritic Stainless Steel: Passive Film Stability and Pitting Nucleation and Growth

et al. 2017

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The aim of the present work was to study the passive film stability and pitting corrosion behavior of the AISI 409 stainless steel. The electrochemical tests were carried out in 0.1 M NaCl solution at room temperature. The general electrochemical behavior was assessed using electrochemical impedance spectroscopy (EIS) measurements whereas the semiconducting properties of the passive film were evaluated by the Mott-Schottky approach. Pitting corrosion was investigated using potentiodynamic and potentiostatic polarization tests. Surface morphology was examined using confocal laser scanning microscopy and scanning electron microscopy (SEM). Energy dispersive X-ray spectroscopy (EDS) analyses were carried out to identify the composition of precipitates that could act as preferential sites for the onset of pitting corrosion. The results showed that the passive film presents n-type semiconductive behavior. Grain boundaries played an important role as pitting initiation sites for the AISI 409 stainless steel.

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Section: Introductionmentioning

confidence: 96%

Electrochemical Study of the AISI 409 Ferritic Stainless Steel: Passive Film Stability and Pitting Nucleation and Growth

et al. 2017

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“…Additionally, grain growth in the HAZ can occur due to high temperatures during welding (Katundi et al, 2010). These aspects tend to modify the mechanical properties and corrosion resistance of the welded joints (Okada et al, 1999;Bayraktar et al, 2011;Niekerk and Toit, 2011;Lakshminarayanan and Balasubramanian, 2012).…”

Section: Introductionmentioning

confidence: 99%

Heat input effect on the microstructural transformation and mechanical properties in GTAW welds of a 409L ferritic stainless steel

et al. 2016

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Welds without filler metal and welds using a conventional austenitic stainless steel filler metal (ER308L) were performed to join a ferritic stainless steel with Gas Tungsten Arc Welding process (GTAW). Welding parameters were adjusted to obtain three different heat input values. Microstructure reveals the presence of coarse ferritic matrix and martensite laths in the Heat Affected Zone (HAZ). Dilution between filler and base metal was correlated with the presence of austenite, martensite and ferrite in the weld metal. Weld thermal cycles were measured to correlate the microstructural transformation in the HAZ. Microhardness measurements (maps and profiles) allow to identify the different zones of the welded joints (weld metal, HAZ, and base metal). Comparing the base metal with the weld metal and the HAZ, a hardness increment (~172 HV 0.5 to ~350 HV 0.5 and ~310 HV 0.5 , respectively) was observed, which has been attributed to the martensite formation. Tensile strength of the welded joints without filler metal increased moderately with respect to base metal. In contrast, ductility was approximately 25% higher than base metal, which provided a toughness improvement of the welded joints. RESUMEN:Efecto del calor de aporte sobre la transformación microestructural y las propiedades mecánicas en soldadura GTAW de un acero inoxidable ferrítico 409L. Se llevaron a cabo soldaduras sin material de aporte y empleando un electrodo convencional (ER308L) para unir un acero inoxidable ferrítico, empleando el proceso de soldadura de arco con electrodo de tungsteno (GTAW). Los parámetros de soldadura fueron ajustados para obtener tres valores diferentes de calor de aporte. La microestructura revela la presencia de una matriz ferrítica gruesa y placas de martensita en la Zona Afectada por el Calor (ZAC). La dilución entre el metal base y de aporte fue correlacionada con la presencia de austenita, martensita y ferrita en el metal de soldadura. Los ciclos térmicos de la soldadura fueron medidos para correlacionar la transformación microestrutural en la ZAC. Mediciones de microdureza (mapas y perfiles), permitieron identificar las diferentes zonas de las uniones soldadas (metal base, ZAC y metal de soldadura). Se observó un incremento de dureza en el metal de soldadura (~350 HV 0,5 ) y en la ZAC (~310 HV 0,5 ), en relación al metal base (~172 HV 0,5 ), que se ha atribuido a la formación de martensita. La resistencia a la tensión de las uniones soldadas sin metal de aporte aumentó ligeramente con respecto al metal base. En cambio, la ductilidad se incrementó aproximadamente un 25% en relación al material base, lo cual mejoró la tenacidad de las uniones.

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“…Embora a liga em estudo apresente uma concentração de carbono baixa, a redução dos teores de carbono abaixo de 0,03% não previne a sensitização, visto que a precipitação de carbonetos de cromo pode ocorrer rapidamente quando estes aços se encontram dentro da faixa temperatura para precipitação [28]. Van Niekerk e colaboradores [29] verificaram a ocorrência de sensitização em um aço inoxidável ferrítico contendo 12% Cr, mesmo com uma concentração de carbono de 0,011%, dependendo da energia de soldagem aplicada. Matthews et al [30] reportam que para menores velocidades de resfriamento a transformação martensítica é precedida de uma precipitação de carbonetos nos contornos de grão da austenita em alta temperatura.…”

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Microestrutura de uma Solda Dissimilar entre o Aço Inoxidável Ferrítico AISI 410S e o Aço Inoxidável Austenítico AISI 304L Soldado pelo Processo FSW

et al. 2015

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Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution Non-Commercial, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que sem fins comerciais e que o trabalho original seja corretamente citado.Recebido: 04 Set., 2015 Aceito: 18 Dez., 2015 E-mail: cleiton@metalmat.ufc.br (CCS)Resumo: O presente trabalho visa investigar a microestrutura formada na soldagem dissimilar entre chapas de aços inoxidáveis ferríticos AISI 410S e aços inoxidáveis austeníticos AISI 304L pelo processo friction stir welding. A soldagem foi realizada com o ajuste dos seguintes parâmetros: rotação 450 rpm; velocidade de soldagem de 1,0 mm/s; e força axial 40 kN. O aço AISI 410S foi posicionado no lado de avanço enquanto que o aço AISI 304L foi posicionado no lado de retrocesso. A análise consistiu de preparação metalográfica e caracterização microestrutural por microscopia ótica e microscopia eletrônica de varredura. Para o aço AISI 410S foi observada a formação de martensita associada com ferrita na zona de mistura (ZM), zona termomecanicamente afetada (ZTMA) e na zona afetada pelo calor (ZAC). As características do processo de soldagem FSW resultaram num refino de grão para o aço inoxidável ferrítico, posicionado no lado de avanço, tanto na ZM quanto nas ZTMA e ZAC. O mesmo comportamento não foi observado para o lado austenítico.Palavras-chave: Soldagem dissimilar; Friction stir welding; Aço inoxidável; Refino de grão. Microstructure of AISI 410S Ferritic Stainless Steel and AISI 304L Austenitic Stainless Steel Dissimilar Weld Joined by FSW ProcessAbstract: This study aims to investigate the microstructure formed in dissimilar welding between AISI 410S ferritic stainless steel and AISI 304L austenitic stainless steels plates by friction stir welding process. The welding was performed setting the following parameters: rotation 450 rpm; welding speed of 1.0 mm/s; and axial force 40 kN. The AISI 410S was positioned on the advancing side while the AISI 304L steel was positioned in the retracting side. The analysis consisted of metallographic preparation and microstructural characterization by optical microscopy and scanning electron microscopy. For AISI 410S ferritic stainless steel was found martensite formation in association with ferrite in the stir zone (SZ), thermomechanically affected zone (TMAZ) and heat-affected zone (HAZ). The characteristics of the FSW welding process for the ferritic stainless steel resulted in grain refining, whether in the SZ, TMAZ and HAZ. In the austenitic stainless steel side, the same behavior was not found. Key-words: Dissimilar welding; Friction stir welding; Stainless steel; Grain refining. IntroduçãoQuando comparados aos aços inoxidáveis austeníticos, os aços inoxidáveis ferríticos fornecem aproximadamente a mesma resistência à corrosão, porém possuem mais baixa ductilidade, tenacidade e soldabilidade [1]. Podem ser usados em uma grande variedade de aplicações quando a resistência à corrosão por pites e/ou resistência à corrosão...

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Sensitization Of Aisi 409 Ferritic Stainless Steel During Low Heat Input Arc Welding

Cited by 22 publications

References 6 publications

Electrochemical Study of the AISI 409 Ferritic Stainless Steel: Passive Film Stability and Pitting Nucleation and Growth

Electrochemical Study of the AISI 409 Ferritic Stainless Steel: Passive Film Stability and Pitting Nucleation and Growth

Heat input effect on the microstructural transformation and mechanical properties in GTAW welds of a 409L ferritic stainless steel

Microestrutura de uma Solda Dissimilar entre o Aço Inoxidável Ferrítico AISI 410S e o Aço Inoxidável Austenítico AISI 304L Soldado pelo Processo FSW

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