On the Nitrogen Diffusion in a Duplex Stainless Steel

Bobadilla, Margarita; Tschiptschin, André Paulo

doi:10.1590/1516-1439.337714

Cited by 33 publications

(22 citation statements)

References 20 publications

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“…A few paper reported on the plasma nitriding of austenitic stainless steels at 623 K 13) and on the nitrogen diffusion process in low temperature. 14) The nitrided layer thickness was 2.0 μm and the nitrogen diffusion coefficient was estimated to be 2.7 × 10 − 16 m 2 /s in 13).…”

Section: Discussionmentioning

confidence: 99%

Grain Size Effect on the Nitrogen Super-Saturation Process into AISI316 at 623 K

et al. 2019

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Coarse and fine grained AISI316 substrates were prepared to describe the grain size effect on the inner nitriding behavior at 623 K by using the high density plasma nitriding without precipitation of nitrides. In case of coarse grained AISI316, the nitriding process advanced homogeneously in one part of nitrided layer with high nitrogen content, and, heterogeneously in its other part. In the former, γ-α ' two-phase, fine microstructure was uniformly formed by the phase transformation and plastic straining with the nitrogen supersaturation. In the latter, the nitrogen super-saturation localized to selectively modify the coarse grains to form the transformed α '-phase zones with the plastically strained γ-phase ones, even below the nitriding front end of 30 μm. In case of fine-grained AISI316, the nitriding took place homogeneously to form fine, two-phase microstructure down to the nitriding front end of 40 μm. This difference in the inner nitriding behavior came from the synergetic relationship between the nitrogen diffusion and super-saturation processes.

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Section: Discussionmentioning

confidence: 99%

Grain Size Effect on the Nitrogen Super-Saturation Process into AISI316 at 623 K

et al. 2019

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“…It was observed that the thickness over the two phases (austenite and ferrite) is different in the case of plasma nitride specimens, whereas such a difference was not found in the plasma nitrocarburized samples. However, it was also described that treatments above 500 • C lead to similar thicknesses over both phases [57].…”

Section: Surface Modification Technologiesmentioning

confidence: 95%

“…The reason for the difference in nitrogen diffusion into the austenite and ferrite phases was discussed by Pinedo et al [49] and Bobadilla and Tschiptschin [57]. Diffusion of nitrogen not only occurs in the volume of the substrate but also through the grain boundaries.…”

Section: Surface Modification Technologiesmentioning

confidence: 99%

Duplex and Superduplex Stainless Steels: Microstructure and Property Evolution by Surface Modification Processes

Biserova-Tahchieva

Llorca-Isern

Cabrera

2019

Metals

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The paper presents an overview of diffusion surface treatments, especially nitriding processes, applied to duplex and superduplex stainless steels in the last five years. Research has been done mainly to investigate different nitriding processes in order to optimize parameters for the most appropriate procedure. The scope has been to improve mechanical and wear resistance without prejudice to the corrosion properties of the duplex and superduplex stainless steels. Our investigation also aimed to understand the effect of the nitriding layer on the precipitation of secondary phases after any heating step.

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“…Moreno et al 17 determined using electron probe microanalysis (EPMA) technique an average content of N 2 in the range 0.045% -0.070%wt in ferrite and 0.520% -0.770%wt in austenite for five different DSS alloys. The addition of C and N 2 strengthens both ferrite and austenite by dissolving at interstitial sites in the solid solution 2,16,17,18 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Nitrogen Addition to Shielding Gas on Cooling Rates and in the Microstructure of Thin Sheets of Duplex Stainless Steel Welded by Pulsed Gas Tungsten Arc Welding Process

et al. 2019

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The effect of the nitrogen content in the shielding gas and its effect on temperature distributions at the welded zone of thin sheets of duplex stainless steel have been evaluated. The duplex stainless steels have many features due to unique microstructural combination of austenite and ferrite grains. The phase balance can be easily shifted depending on the welding parameters. Two sheets were welded using pure argon and pure argon plus 2% of nitrogen as shielding gas. The thermal profile had shown that N 2-supplemented shielding gas lead to higher peaks of temperature using similar welding parameters. Microstructural examination showed that the austenite phase in the weld increased with the presence of nitrogen in the shielding gas. The added nitrogen promoted primary austenite formation and slightly increases the microhardness at the solidified zone. Microhardness mapping and metallographic imaging presented information about microstructures, confirming the formation of secondary phases during thermal cycle in the temperature range 850 °C and 950 °C. Control of ferrite amounts in the welds is essential mainly to improve mechanical properties and corrosion resistance of welding zones.

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On the Nitrogen Diffusion in a Duplex Stainless Steel

Cited by 33 publications

References 20 publications

Grain Size Effect on the Nitrogen Super-Saturation Process into AISI316 at 623 K

Grain Size Effect on the Nitrogen Super-Saturation Process into AISI316 at 623 K

Duplex and Superduplex Stainless Steels: Microstructure and Property Evolution by Surface Modification Processes

Effect of Nitrogen Addition to Shielding Gas on Cooling Rates and in the Microstructure of Thin Sheets of Duplex Stainless Steel Welded by Pulsed Gas Tungsten Arc Welding Process

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