Micro-Structural Characterization and Semi Quantitative Chemical Analysis of Ferrite and Austenite Phases in Duplex Stainless Steels

11 Pages Posted: 14 Jan 2019

See all articles by André de Albuquerque Vicente

André de Albuquerque Vicente

University of São Paulo (USP)

Amilton Barbosa Botelho Junior

University of São Paulo (USP)

Joao Roberto Sartori Moreno

Universidade Tecnológica Federal do Paraná

Tiago Felipe Abreu Santos

Universidade Federal de Pernambuco (UFPE)

Denise Crocce Romano Espinosa

University of São Paulo (USP) - Escola de Engenharia de Lorena, Chemical Engineering Department

Jorge Alberto Soares Tenório

University of São Paulo (USP)

Date Written: January 3, 2019

Abstract

The PREN value of the alloy may lead to a misleading prediction of pitting corrosion resistance because in the event of an imbalance of δ ferrite and austenite volume fraction, by Quantitative metallographic analyzes. In this work three laminated duplex stainless steels with different PRENs were characterized: UNS S32304 (Lean Duplex), UNS S31803 (Duplex) and UNS S32750 (Super Duplex), where several techniques of microstructural analysis were used, such as optical emission spectrometry, optical microscopy and scanning electron microscopy/EDS. For all the alloys studied, it was observed that the δ ferrite phase presents higher Cr and Mo contents than the austenite phase, which in turn had Ni contents higher than the δ ferrite. Therefore we can observe that the PRENN values for the Super Duplex alloy were generally higher, as well as in the ferritic and austenitic phase, at a level of 12.25% in relation to Duplex, and more than 50% higher than Lean Duplex, which leads to the definition of the alloy having greater resistance to pitting corrosion.

Keywords: Lean Duplex; Duplex Stainless Steels; PREN; Volume Fraction; δ Ferrite Phase

Suggested Citation

Vicente, André de Albuquerque and Botelho Junior, Amilton Barbosa and Sartori Moreno, Joao Roberto and Abreu Santos, Tiago Felipe and Romano Espinosa, Denise Crocce and Soares Tenório, Jorge Alberto, Micro-Structural Characterization and Semi Quantitative Chemical Analysis of Ferrite and Austenite Phases in Duplex Stainless Steels (January 3, 2019). Available at SSRN: https://ssrn.com/abstract=3309760 or http://dx.doi.org/10.2139/ssrn.3309760

André de Albuquerque Vicente

University of São Paulo (USP) ( email )

Rua Luciano Gualberto, 315
São Paulo, São Paulo 14800-901
Brazil

Amilton Barbosa Botelho Junior

University of São Paulo (USP) ( email )

Rua Luciano Gualberto, 315
São Paulo, São Paulo 14800-901
Brazil

Joao Roberto Sartori Moreno (Contact Author)

Universidade Tecnológica Federal do Paraná ( email )

Via do Conhecimento, Km 01
Pato Branco, Paraná 85503-390
Brazil

Tiago Felipe Abreu Santos

Universidade Federal de Pernambuco (UFPE) ( email )

Cidade Universitária
Cidade Universitária, Pernambuco 50670-901
Brazil

Denise Crocce Romano Espinosa

University of São Paulo (USP) - Escola de Engenharia de Lorena, Chemical Engineering Department ( email )

São Paulo
Brazil

Jorge Alberto Soares Tenório

University of São Paulo (USP) ( email )

Rua Luciano Gualberto, 315
São Paulo, São Paulo 14800-901
Brazil

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