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Abstract

An ATEM study of the mechanisms of the secondary phase precipitation in the temperature range of 600-800 degrees Celsius was undertaken for two P/M-HIP super duplex stainless steel grades. It was shown that the main secondary phase precipitating after the aging treatment of 600 degrees Celsius for 10 h is R phase. After the treatment of 700 degrees Celsius for 2hrs, secondary austenite forms by the Widmannstatten mechanism. The major intermetallic precipitate is R phase. After the treatment of 800 degrees Celsius for 30 min, ferrite decomposes by the eutectoid reaction õÓ¾+Ò2 producing significant amounts of sigma ¾ phase and secondary austenite. The changes in morphology and composition of the secondary phases are discussed from the point of view of the precipitation mechanisms and resulting effects on mechanical and corrosion properties of the studied super duplex stainless steels. The effects of copper alloying are also discussed.

Additional information

Authors: SMUK O, Helsinki University of Technology, (FI);NENONEN P, VTT Manufacturing Technology (FI);HANNINEN H, JRC-Institute Advanced Materials, Petten (NL)
Bibliographic Reference: Oral report given at: The 6th World Conference and Expo: Duplex 2000. Organized by: Associazione Italiane Mettallurgia. Held at: Venezia (IT), 17-20 October 2000
Record Number: 200013204 / Last updated on: 2001-03-23
Category: PUBLICATION
Original language: en
Available languages: en