Influence of inclusion and grain boundary on corrosion behaviour of low alloy steel in cargo oil tank bottom plate environment. (October 2014)

• Record Type: Journal Article
• Authors: Liang, J. M.; Wu, H. B.; Tang, D.; Zhang, P. C.; Liu, X. T.
• Is Part Of: Corrosion engineering, science, and technology. Volume 49:Number 7(2014)
• Page Start: 633
• Page End: 642
• Publication Date: 2014-10
• Subjects: Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1179/1743278214Y.0000000161
• Languages: English
• ISSNs: 1478-422X

Abstract

<abstract> <title> <x content-type="archive" xml:space="preserve">Abstract</x> </title> <p>Corrosion behaviours of low alloy steels with various alloying element contents were studied in simulated corrosion environment (pH = 0·85, 10% NaCl solution) of cargo oil tank (COT) bottom plate corrosion environment. Corrosion rate was measured, and the surface morphology of test steels was characterised using scanning electron microscope (SEM). The electrochemical results were investigated using polarisation curves and electrochemical impedance spectroscopy (EIS). The corrosion behaviour of inclusion was investigated using <italic>in situ</italic> SEM images and energy disperse spectroscopy (EDS) analysis. The effect of misorientation distribution on corrosion resistance of steel was evaluated using electron backscattered diffraction microscopy. The results showed that MnS dissolved into the simulated COT corrosion solution before steel matrix, whereas TiO₂ would not be dissolved. A 10–20 μm area was formed as a circular cathode around inclusion centre. The corrosion was inclined to occur in the place where curvature radius of inclusion is small. An increase in the proportion of low energy grain boundaries was conducive to the improvement of corrosion resistance especially in the early stages of corrosion.</p> </abstract>