The Corrosion Features of Q235B Steel under Immersion Test and Electrochemical Measurements in Desulfurization Solution

Abstract

With the continuous tightening marine diesel engines emission standards, removing sulfur oxides (SOX) by sodium hydroxide solution absorption is a highly efficiency and economic method, which has been a hot area of research. The ensuing desulfurization solution is a new corrosive system, the aim of this paper is to ascertain the corrosion feature of Q235B steel in desulfurization solution, which lays a theoretical foundation for industrialization. For this purpose, mass loss, electrochemical techniques and surface analyses were applied. The results of mass loss highlight a reduction in the corrosion rate with 35 days of immersion. Higher exposure time increased the compactness of the corrosion product layer and changed phase composition. These conclusions are supported by surface analyses, such as X-ray diffraction and scanning electron microscope. However, electrochemical results showed that the polarization resistance Rp was fluctuant. Both of Rp and charge transfer resistance Rt reach a maximum after immersing 21 days. In addition, although the sediments attached to the steel surface could inhibit corrosion, pitting corrosion aggravated by hydrolyzation of FeSO4 should be given more attention.

Multiscale Statistical Analysis of Massive Corrosion Pits Based on Image Recognition of High Resolution and Large Field-of-View Images

“…The initiation and propagation mechanisms of a single pit for different structural materials, including high strength pipeline steels, have been extensively studied in the past decades. These studies typically involve electrochemical measurement [9,10], characterization of typical corrosion morphologies [11] and numerical modeling [12]. The past studies in literature reveal that the inclusions in steel play a critical role in the pitting initiation [13][14][15].…”

Special Issue: Corrosion Properties and Mechanism of Steels

“…Wang et al [ 11 ] investigated the effects of Ti and Cu addition on inclusion modification and corrosion behavior in the simulated coarse-grained heat-affected zone of low-alloy steels by using an in situ scanning vibration electrode technique, a scanning electron microscope/energy-dispersive X-ray spectroscopy and an electrochemical workstation. The corrosion feature of Q235B steel in desulfurization solution is studied by Gong et al [ 12 ]. The research results presented in the article are related to the tightening of marine diesel engine emission standards.…”