Synergistic Erosion-Corrosion Behavior of AISI 2205 Duplex Stainless Steel Elbows in Potash Brine-Sand Slurry and the As

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JMEPEG https://doi.org/10.1007/s11665-020-05195-w

Synergistic Erosion-Corrosion Behavior of AISI 2205 Duplex Stainless Steel Elbows in Potash Brine-Sand Slurry and the Associated Microstructural Changes Raheem Elemuren, Richard Evitts, Ikechukwuka N.A. Oguocha, Jerzy Szpunar, Glyn Kennell, Regan Gerspacher, A.A. Tiamiyu, and Akindele G. Odeshi (Submitted January 17, 2020; in revised form August 21, 2020; Accepted September 20, 2020) Slurry erosion-corrosion damage to materials used in mineral processing industries occurs due to the combined effects of electrochemical and mechanical processes. In this study, AISI 2205 duplex stainless steel elbows were tested in a flow loop using slurries consisting 10, 20, 30, 40 and 50 wt.% sand particles and saturated potash brine. Erosion-corrosion tests were conducted at flow velocities of 2.5 and 4.0 m/s. The results of the gravimetric analysis revealed that erosion-corrosion rates increased with increasing particle concentration at both velocities. The elbows exhibited negative synergy for all operating conditions, which is attributed to the presence of passive oxide film on the surface. Microstructural examination of the eroded surfaces showed that materials removal occurred by cutting and plastic deformation. Electron backscattered diffraction analysis suggests that plastic deformation, which occurred approximately 4 lm below the eroded surface, led to the transformation of metastable austenite phase to martensite.

Raheem Elemuren, Ikechukwuka N.A. Oguocha, Jerzy Szpunar, A.A. Tiamiyu, and Akindele G. Odeshi, Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada; and Richard Evitts, Glyn Kennell, and Regan Gerspacher, Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9, Canada. Contact e-mail: [email protected].

Journal of Materials Engineering and Performance

Keywords

duplex stainless steel, EBSD, erosion-corrosion, phase transformation, wear, XRD

1. Introduction

2. Experimental Procedures

Duplex stainless steels are used in applications where high resistance to corrosion and good mechanical strength are required. They have a dual-phase microstructure consisting of austenite (c) and ferrite (a). As the austenite phase in duplex steels are metastable, their exposure to particle impacts at high velocities during erosion-corrosion may lead to deformationinduced martensitic transformation (Ref 1), thereby altering their mechanical properties and corrosion resistance. Aribo et al. (Ref 1) investigated the erosion-corrosion performance of AISI 2101 duplex stainless steel in slurries consisting of 3.5% NaCl solution and 500 mg/l silica sand particles. They reported that some volume fraction of the austenite phase present in the duplex stainless steel were transformed to martensite due to the impingement of the high-flowing solid particles on the surface of the alloy at a velocity of 15 m/s. The resistance of duplex stainless steels to corrosion in a wide variety of environments