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Liu et al. Microstructures 2023;3:2023020 Microstructures
DOI: 10.20517/microstructures.2023.02

Review Open Access

A review on pitting corrosion and environmentally

assisted cracking on duplex stainless steel

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Menghao Liu , Cuiwei Du , Zhiyong Liu , Li Wang , Rui Zhong , Xiaojie Cheng , Jiawei Ao , Teng Duan ,
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Yuetong Zhu , Xiaogang Li 1
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Institute for Advanced Material and Technology, University of Science and Technology Beijing, Beijing 100083, China.
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Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China.
Correspondence to: Prof. Cuiwei Du, Institute for Advanced Material and Technology, University of Science and Technology
Beijing, Beijing 100083, China. E-mail: dcw@ustb.edu.cn
How to cite this article: Liu M, Du C, Liu Z, Wang L, Zhong R, Cheng X, Ao J, Duan T, Zhu Y, Li X. A review on pitting corrosion
and environmentally assisted cracking on duplex stainless steel. Microstructures 2023;3:2023020.
https://dx.doi.org/10.20517/microstructures.2023.02
Received: 16 Jan 2023 First Decision: 3 Mar 2023 Revised: 7 Mar 2023 Accepted: 28 Mar 2023 Published: 18 Apr 2023
Academic Editor: Xiaozhou Liao Copy Editor: Fangling Lan Production Editor: Fangling Lan
Abstract
Duplex stainless steel is widely used in the petrochemical, maritime, and food industries. However, duplex stainless
steel has the problem of corrosion failures during use. This topic has not been comprehensively and academically
reviewed. These factors motivate the authors to review the developments in the corrosion research of duplex
stainless steel. The review found that the primary reasons for the failure of duplex stainless steels are pitting
corrosion and chloride-induced stress corrosion cracking. After being submerged in water, the evolution of the
passive film on the duplex stainless steel can be loosely classified into three stages: nucleation, rapid growth, and
stable growth stages. Instead of dramatic rupture, the passive film rupture process is a continuous metal oxidation
process. Environmental factors scarcely affect the double-layer structure of the passive film, but they affect the
film's overall thickness, oxide ratio, and defect concentration. The six mechanisms of alloying elements on pitting
corrosion are summarized as stabilization, ineffective, soluble precipitates, soluble inclusions, insoluble inclusions,
and wrapping mechanisms. In environments containing chlorides, ferrite undergoes pitting corrosion more easily
than austenite. However, the pitting corrosion resistance reverses when sufficiently large deformation is used.
The mechanisms of pitting corrosion induced by precipitates include the Cr-depletion, microgalvanic, and high-
stress field theories. Chloride-induced cracks always initiate in the corrosion pits and blunt when encountering
austenite. Phase boundaries are both strong hydrogen traps and rapid hydrogen diffusion pathways during
hydrogen-induced stress cracking.

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