Duplex stainless steel

US9637813B2 · kind B2 · utility

Assignee

• Outokumpu Oyj · FI

Inventors

• Alexander Thulin · Luleå, SE
• Jan Y. Jonsson · Avesta, SE
• Mats Liljas · Avesta, SE
• Rachel Pettersson · Norrtälje, SE
• Jan Andersson · Ystad, SE
• Staffan Hertzman · Nacka, SE

Key dates

• Filing date: Nov 1, 2012
• Grant date: May 2, 2017
• Expiry date: Sep 26, 2033

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D2211/005
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The present invention relates to duplex ferritic austenitic stainless steel for the use chemical industry for nitric acid environments wherein good uniform corrosion resistance and high strength are required. The microstructure of the stainless steel has 35-65 volume % of ferrite, preferably 45-55 volume % of ferrite, the balance being austenite. The chemical composition contains less than 0.03 weight % carbon, less than 1 weight % silicon, less than 3 weight % manganese, 26-29.5 weight % chromium, 5-8.5 weight % nickel, 1-3 weight % molybdenum, 0.25-0.35 weight % nitrogen, 1-3 weight % copper, the rest being iron and inevitable impurities occurring in stainless steels.