Effects of .ALPHA./.GAMMA. phase ratio and N addition on the corrosion resistance of Si-bearing duplex stainless steel in nitric acid.

Kajimura, Haruhiko; Ogawa, Kōichi; Nagano, Hiroo

doi:10.2355/isijinternational.31.216

Cited by 16 publications

(7 citation statements)

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“…Localized uneven distribution of ferrite/austenite with 80-90% ferrite in weld is found [13]. The weldability of duplex stainless steels has been improved by the addition of nitrogen to stabilize the austenite at elevated temperatures [14], with an enhancement of mechanical and corrosion properties [15][16][17][18][19]. On the other hand, the re-precipitation of austenite from δ-ferrite is also enhanced due to a higher nitrogen content in modern duplex stainless steels [20].…”

Section: Microstructuresmentioning

confidence: 99%

Additive manufacture of superduplex stainless steel using WAAM

Eriksson

Lervåg²,

Sørensen³

et al. 2018

MATEC Web Conf.

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Superduplex stainless steels have been used in the oil and gas industry for a couple of decades due to the combination of excellent mechanical properties and corrosion resistance. The present investigation addresses the applicability of wire and arc additive manufacturing for this steel grade. Due to the inherent rapid heating and cooling, the initial base metal microstructure will be substantially altered, and complex thermal cycles may cause the formation of brittle secondary phases, among which the frequently observed intermetallic sigma phase is most harmful. However, no intermetallic phases have been observed, which is consistent with the low heat input employed, and the high Ni content in the wire. The microstructure observations in terms of ferrite volume fraction, Cr nitrides precipitation and the formation of secondary austenite are discussed together with the hardness measurements, tensile testing and notch toughness testing. It is concluded that additive manufacturing of superduplex stainless steels by wire and arc process is feasible.

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Section: Microstructuresmentioning

confidence: 99%

Additive manufacture of superduplex stainless steel using WAAM

Eriksson

Lervåg²,

Sørensen³

et al. 2018

MATEC Web Conf.

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“…[9,10,11] This chromium nitride precipitation has been shown to severely impair the corrosion resistance and the toughness of the DSSs. [10][11][12][13][14][15][16][17][18] When the material in this metastable condition is reheated, as in multipass welding, the most apparent changes in the microstructure are the dissolution of the intragranular nitrides and the precipitation of secondary austenite (␥ 2 ). [19,21] The ␥ 2 precipitation improves the toughness of the material.…”

Section: Introductionmentioning

confidence: 99%

The relationship between chromium nitride and secondary austenite precipitation in duplex stainless steels

Ramírez

Lippold

Brandi

2003

Metall Mater Trans A

299

152

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A detailed investigation of the early stages of secondary austenite precipitation in five duplex stainless steel (DSS) commercial alloys (UNS S32304, S32205, S32550, S32750, and S32760) has been conducted using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on this study, a model is proposed that describes the interaction between Cr 2 N and austenite (intergranular and intragranular) precipitation in these alloys. Depending on nitrogen availability and interface mobility, Cr 2 N precipitation along existing ferrire/austenite interfaces precedes intergranular secondary austenite growth. The low-energy interfaces formed between the Cr 2 N, the ferrite, and the austenite, along with the coupled diffusion processes, are the factors controlling this phase transformation. Finally, in the case of the intragranular nitrides, a mechanism is proposed whereby the nitrides serve as sites for heterogeneous nucleation of intragranular secondary austenite.

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“…Many research works [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] have focused on sigma phase precipitation in duplex stainless steel applicable to the heat treatment, hot work or welding process.…”

Section: Introductionmentioning

confidence: 99%