Effect of aging treatments on microstructure and impact properties of tungsten substituted 2205 duplex stainless steel

• Published in: Materials science and technology Vol. 16; no. 4; pp. 382 - 388
• Main Authors: Ahn, Y.S., Kang, J.P.
• Format: Journal Article
• Language: English
• Published: London, England Taylor & Francis 01.04.2000; SAGE Publications; Maney; Taylor & Francis Ltd
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fractures; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Precipitation; Solid-phase precipitation; Alloy steel; Precipitation; Dual-phase steels; Tungsten additions; Aging; Composition effect; Experimental study; Microstructure; Heat treatments; Tenacity; Stainless steels
• ISSN: 0267-0836; 1743-2847
• DOI: 10.1179/026708300101507965

The effects of partial substitution of tungsten for molybdenum on the microstructure and impact properties in 22Cr-5Ni-3Mo (wt-%) duplex stainless steel (DSS) have been investigated following aging heat treatments in the temperature range 600-1000°C. During aging the intermetallic σ and χ phases were precipitated, and the impact toughness was significantly decreased with an increase in the σ phase content. The χ phase had been precipitated on the α/γ boundary in the early stages of aging. Ferrite and χ phases in tungsten substituted duplex stainless steel contain a large amount of tungsten, and their decomposition rates are much lower compared with those in steel containing only molybdenum. Consequently, the precipitation of the σ phase is retarded in tungsten substituted DSSs, which results in high impact toughness. However, after aging for a long time, the α and χ phases transformed to the σ and austenite phases in the tungsten substituted steels, and the steels showed low impact toughness.