The relationship between solidification and microstructure in austenitic and austenitic-ferritic stainless steel welds

Suutala, N.; Takalo, T.; Moisio, T.

doi:10.1007/bf02697081

Cited by 166 publications

(53 citation statements)

References 2 publications

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“…The SEM observations of various weld metal microstructure at room temperature of some selected AISI 304 samples welded with duplex 2205 are listed in Figure 11. Generally, the final microstructure of all the weldments can be standardized by the chemical composition of the parent metals and the thermal cycle of the welding process, as the stainless steel welds had four potential solidification modes namely, fully ferritic, primary ferritic, primary austenitic, and fully austenitic [65,66]. Figure 11.…”

Section: Metallography and Visual Examinationmentioning

confidence: 99%

Fiber Laser Welding of Dissimilar 2205/304 Stainless Steel Plates

Mohammed

Ishak

Ahmad

et al. 2017

Metals

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Abstract:In this study, an attempt on pulsed-fiber laser welding on an austenitic-duplex stainless steel butt joint configuration was investigated. The influence of various welding parameters, such as beam diameter, peak power, pulse repetition rate, and pulse width on the weld beads geometry was studied by checking the width and depth of the welds after each round of welding parameters combination. The weld bead dimensions and microstructural progression of the weld joints were observed microscopically. Finally, the full penetration specimens were subjected to tensile tests, which were coupled with the analysis of the fracture surfaces. From the results, combination of the selected weld parameters resulted in robust weldments with similar features to those of duplex and austenitic weld metals. The weld depth and width were found to increase proportionally to the laser power. Furthermore, the weld bead geometry was found to be positively affected by the pulse width. Microstructural studies revealed the presence of dendritic and fine grain structures within the weld zone at low peak power, while ferritic microstructures were found on the sides of the weld metal near the SS 304 and austenitic-ferritic microstructure beside the duplex 2205 boundary. Regarding the micro-hardness tests, there was an improvement when compared to the hardness of duplex and austenitic stainless steels base metals. Additionally, the tensile strength of the fiber laser welded joints was found to be higher when compared to the tensile strength of the base metals (duplex and austenitic) in all of the joints.

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Section: Metallography and Visual Examinationmentioning

confidence: 99%

Fiber Laser Welding of Dissimilar 2205/304 Stainless Steel Plates

Mohammed

Ishak

Ahmad

et al. 2017

Metals

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“…Afim de prever o modo de solidificação dos aços inoxidáveis através das expressões de cromo e niquel equivalentes propostas por O. Hammar e Svensson [6,10], Suutala e Moisio [11] rearranjaram os resultados obtidos em diversos trabalhos [5,7,[12][13][14][15][16] com diferentes velocidades de solidificação. Quando a relação Creq/Nieq <1,5 a solidificação poderá ser austenítica (modo I) ou austenítica-ferrítica (modo II).…”

Section: Efeito Dos Gases De Proteção Na Microestrutura E Nas Cinéticunclassified

Efeito Dos Gases De Proteção Na Microestrutura E Nas Cinéticas De Oxidação a Altas Temperaturas Ao Ar De Juntas Soldadas De Um Aço Inoxidável Austenítico Através Do Processo Mig/Mag

Vicente¹,

Cabral²,

Espinosa³

et al. 2017

Tecnologia Em Metalurgia Materiais E Mineração

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ResumoForam estudadas as microestruturas e as cinéticas de oxidação a altas temperaturas ao ar de quatro juntas soldadas de um aço inoxidável austenítico produzidas através do processo MIG/MAG com diferentes gases de proteção. Utilizou-se o metal de adição 22.12.HT e diferentes gases de proteção: 100% Ar, Ar + 2% CO 2 , Ar +4% CO 2 e Ar + 20% CO 2 . Para cada mistura gasosa, foi soldado um corpo de prova. Estudou-se a variação das frações volumétricas de ferrita delta em função dos diferentes gases de proteção utilizados. Observou-se aumento no teor de carbono e consequente diminuição das frações volumétricas de ferrita delta, diminuições significativas nos teores de Cr, Si e Mn em relação à composição química do consumível de soldagem e consequente diminuição da resistência à oxidação a altas temperaturas ao ar dos metais depositados com gases de proteção com maiores concentrações de CO 2 . Palavras-chave: Aços inoxidáveis; Gases de proteção; Fração volumétrica; Oxidação a altas temperaturas; MIG/MAG. EFFECT OF SHIELDING GAS IN MICROSTRUCTURE AND KINECTICS OF HIGH TEMPERATURE OXIDATION IN AIR OF WELDED JOINTS OF AN AUSTENITIC STAINLESS STEEL THROUGH THE MIG/MAG PROCESS AbstractThe microstructures and the high temperature oxidation kinectics in air of four welded joints of austenitic stainless steel produced by the MIG/MAG process with different shielding gases were studied. Were used the welding wire 22.12. HT, and different shielding gases: 100% Ar, Ar + 2% CO 2 , Ar +4% CO 2 and Ar + 20% CO 2 . For each gas mixture was welded a specimen. The variation of the volume fractions of delta ferrite according to the different shielding gases used, were studied. There was an increase in carbon content and decreasing of volume fraction of delta ferrite, a decrease in Cr, Si and Mn content when compared with the chemical composition of the welding wire decreasing the high temperature oxidation resistance in air of weld metals deposited with shielding gases with higher concentrations of CO 2 . Keywords: Stainless steels; Shielding gases; Volume fraction; High temperature oxidation; MIG/MAG. INTRODUÇÃOAlém do ferro, cromo e níquel, os aços inoxidáveis têm em sua composição outros elementos químicos que podem estabilizar a ferrita e a austenita. Levando em conta os seus efeitos ferritizantes e austenitizantes, Schaeffler [1] agrupou estes elementos em duas expressões denominadas de cromo equivalente e níquel equivalente, respectivamente e propôs um diagrama que é apresentado na Figura 1. O diagrama de Schaeffler não é um diagrama de equilíbrio. Ele foi determinado experimentalmente com o objetivo de prever-se o teor de ferrita delta em soldas de aços inoxidáveis.Além das expressões de cromo equivalente (Creq=%Cr+%Mo+1,5%Si+0,5%Nb) e de níquel

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“…In addition five different solidification modes differed depending on the fact whether the secondary phase transformed from the remaining melt or in the solid phase [23].…”

Section: Macrostructure Of the Welded Specimenmentioning

confidence: 99%

Modelling and Characterization of Laser Welded Incoloy 800 Ht Joints

Sathiya¹,

Srirangan²

2016

Adv. Sci. Technol. Res. J.

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This study aims at finding the effect of laser welding speed on incoloy 800 HT. This alloy is one of the potential materials for Generation IV nuclear plants. Laser welding has several advantages over arc welding such as low fusion zone, low heat input and concentrated heat intensity. Three different welding speeds were chosen and CO 2 laser welding was performed. 2D modeling and simulation were done using ANSYS 15 to find out the temperature distribution at different welding speeds and it was found that an increase in the welding speed decreased the temperature. Mechanical properties such as tensile strength, toughness and hardness were evaluated. The effect of welding speed on metallurgical characteristics was studied using optical microscopy (OM), Scanning Electron Microscopy (SEM) with EDS, X-Ray Diffraction (XRD) technique and fractographic analysis. From the results it was found that high welding speed (1400 mm/min) decreased the joint strength. The M23C6 and Ni3Ti carbides were formed in a discrete chain and in a globular form along the grain boundaries of the weld region which increased the strength of the grain boundaries. Fractographic evaluations of the tested specimens for welding speed (1000 and 1200) mm/min showed deep and wide dimples indicating ductile failures.

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The relationship between solidification and microstructure in austenitic and austenitic-ferritic stainless steel welds

Cited by 166 publications

References 2 publications

Fiber Laser Welding of Dissimilar 2205/304 Stainless Steel Plates

Fiber Laser Welding of Dissimilar 2205/304 Stainless Steel Plates

Efeito Dos Gases De Proteção Na Microestrutura E Nas Cinéticas De Oxidação a Altas Temperaturas Ao Ar De Juntas Soldadas De Um Aço Inoxidável Austenítico Através Do Processo Mig/Mag

Modelling and Characterization of Laser Welded Incoloy 800 Ht Joints

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