Characterization of microstructure, chemical composition, corrosion resistance and toughness of a multipass weld joint of superduplex stainless steel UNS S32750

Journal Article · Sun Jul 15 04:00:00 EDT 2007 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2006.07.006· OSTI ID:21003568

Tavares, S S.M. . ^[1]; Pardal, J M ^[1]; Lima, L D ^[1]; Bastos, I N ^[2]; Nascimento, A M ^[3]; Souza, J.A. de ^[1]

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1. Universidade Federal Fluminense, Departamento de Engenharia Mecanica/PGMEC, Rua Passo da Patria, 156, CEP 24210-240, Niteroi/RJ (Brazil)
2. Universidade do Estado do Rio de Janeiro (UERJ), Instituto Politecnico (IPRJ), Nova Friburgo/RJ (Brazil)
3. Universidade Estadual de Campinas (UNICAMP), Departamento de Engenharia Mecanica, Campinas/SP (Brazil)

The superduplex stainless steels have an austeno-ferritic microstructure with an average fraction of each phase of approximately 50%. This duplex microstructure improves simultaneously the mechanical properties and corrosion resistance. Welding of these steels is often a critical operation. In this paper we focus on characterization and analysis of a multipass weld joint of UNS S32750 steel prepared using welding conditions equal to industrial standards. The toughness and corrosion resistance properties of the base metal, root pass welded with gas tungsten arc welding, as well as the filler passes, welded with shielded metal arc welding, were evaluated. The microstructure and chemical composition of the selected areas were also determined and correlated to the corrosion and mechanical properties. The root pass was welded with low nickel filler metal and, as a consequence, presented low austenite content and significant precipitation. This precipitation is reflected in the corrosion and mechanical properties. The filler passes presented an adequate ferrite:austenite proportion but, due to their high oxygen content, the toughness was lower than that of the root pass. Corrosion properties were evaluated by cyclic polarization tests in 3.5% NaCl and H{sub 2}SO{sub 4} media.

• OSTI ID: 21003568
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 7 Vol. 58; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
CHEMICAL COMPOSITION
CORROSION
CORROSION RESISTANCE
FERRITE
FERRITES
FERRITIC STEELS
FILLER METALS
GAS TUNGSTEN-ARC WELDING
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL
POLARIZATION
SHIELDED METAL-ARC WELDING
SODIUM CHLORIDES
STAINLESS STEELS
WELDED JOINTS