University of Oulu

S. Yousefian, A. Zarei-Hanzaki, A. Barabi, H.R. Abedi, M. Moallemi, P. Karjalainen, Microstructure, texture and mechanical properties of a nickel-free high nitrogen duplex stainless steel processed through friction stir spot welding, Journal of Materials Research and Technology, Volume 15, 2021, Pages 6491-6505, ISSN 2238-7854,

Microstructure, texture and mechanical properties of a nickel-free high nitrogen duplex stainless steel processed through friction stir spot welding

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Author: Yousefian, S.1; Zarei-Hanzaki, A.1; Barabi, A.1;
Organizations: 1Hot Deformation and Thermomechanical Processing Laboratory of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran
2School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran
3Centre for Advanced Steels Research, University of Oulu, Box 4200, 90014, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 8.1 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2021-12-13


A nickel-free high nitrogen duplex stainless steel holding high Mn-content was friction stir spot welded under the various rotational speeds. The microstructure/texture evolutions of the joints and the correlated mechanical properties were investigated in detail. The ferrite and austenite constituent massive phases were refined down to the mean grain size of 0.9 μm and 1.1 μm, respectively. The microstructure evolutions revealed the activation of continuous dynamic recrystallization as the main restoration mechanism. This was further verified through the formation of Β- and Α-fiber shear texture in the specimens processed under the various processing condition. Besides the activation of different restoration micro-mechanisms in both ferrite and austenite, dynamic phase transformation of ferrite to austenite was also contributed in grain refinement. The transformation was facilitated by providing more diffusional paths through substructure development and grain refinement. The local and bulk mechanical properties of the joints were also assessed. The outstanding tensile-shear peak load of 12.8 KN obtained for the sample welded at 400 rpm was discussed relying on the developed ultrafine-grained microstructure and the maximum peak extension of 1.7 mm achieved at 600 rpm was attributed to the role of ferrite phase in strain accommodation.

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Series: Journal of materials research and technology
ISSN: 2238-7854
ISSN-E: 2214-0697
ISSN-L: 2238-7854
Volume: 15
Pages: 6491 - 6505
DOI: 10.1016/j.jmrt.2021.11.040
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Copyright information: ©2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (