Corrosion Behaviour of Dual-Phase High Carbon Steel—Microstructure Influence

Abstract

Dual-phase high carbon steel is widely used in mining and in chemical industry applications in highly abrasive environments due to its excellent hardness and abrasion resistance. In recent years, the use of less expensive but more corrosive solutions in industrial processes has become more common. As a result, detailed understanding of the corrosion behaviour of dual-phase high carbon steel is needed; an issue that has, to date, been little-studied. This study investigates in detail the corrosion behaviour of dual-phase high carbon steel in a sodium chloride solution at different times, at the macro-and nano-scale, using various techniques. Using scanning electron microscopy (SEM) and 3D laser-scanning confocal microscopy, the corrosion behaviour of this important industrial steel was investigated at the micro-scale, then by using atomic force microscopy (AFM) it was further investigated at the nano-scale. The results reveal preferential corrosion attack on the retained austenitic phase, rather than the martensite phase, which is due to the carbon partitioning between martensite and austenite in this grade of steel.

Enhancing Corrosion Resistance of High-Carbon Steel by Formation of Surface Layers Using Wastes as Input

“…With relatively smaller grain size of both phases on HCS-B and HCS-D on interface region, it has higher potential risk of corrosion attack than HCS-C. This aspect was due to higher boundary-to-boundary contact and the difference in potential energy between phases, thus, prone to boundary and pitting corrosion [14,15]. The other aspect was because of martensite has higher carbon (C) content than retained austenite that possessed higher iron (Fe) content, resulting martensitic phase acted as cathode, whereas the austenitic phase referred as anode, hence preferential attack on retained austenite [14,15].…”

“…This aspect was due to higher boundary-to-boundary contact and the difference in potential energy between phases, thus, prone to boundary and pitting corrosion [14,15]. The other aspect was because of martensite has higher carbon (C) content than retained austenite that possessed higher iron (Fe) content, resulting martensitic phase acted as cathode, whereas the austenitic phase referred as anode, hence preferential attack on retained austenite [14,15]. As results, bulk properties remained unmodified with layers being formed in three waste-treated samples through the reduction process of the wastes [16] into substrate of the steel.…”

Stress-Induced Phase Transformation and Its Correlation with Corrosion Properties of Dual-Phase High Carbon Steel

“…However, the decrease in the hardness due to the corrosion attack was slightly different in all the samples. One of the reasons is due to less corrosion in the base material [9,10] compared to the other two samples because of the solid-state phase transformation that increased the dislocation density, plastic deformation and residual stress between the constituent phases. Another reason is that corrosion has a negative effect on surface mechanical properties, such as grain boundary corrosion between the interface of martensite and austenite phases, which weakens the overall integrity of each phase, thus reducing the surface hardness properties.…”

“…Recent studies by Handoko et al [9] on dual-phase high carbon steel revealed that a preferential attack on retained austenite was followed by martensite in the corrosion process. This phenomenon was due to the different carbon content in which the martensitic phase possessed a higher percentage as compared to the austenitic phase [9,10].…”

“…Recent studies by Handoko et al [9] on dual-phase high carbon steel revealed that a preferential attack on retained austenite was followed by martensite in the corrosion process. This phenomenon was due to the different carbon content in which the martensitic phase possessed a higher percentage as compared to the austenitic phase [9,10]. Other aspects that influenced this behaviour were the dependency of the different size, shape and volume fraction of the retained austenite, where blocky and lengthy grain size led to the decline of grain boundary density and decreased the dissolution of iron atom movement to trigger a corrosion reaction, thus a decline in grain boundary corrosion and enhanced corrosion resistance properties [10].…”