Slurry and liquid impingement erosion behavior of low-temperature plasma carburized AISI 420 martensitic stainless steel

Abstract

The impact of plasma carburizing treatment on the erosion wear resistance of AISI 420 martensitic stainless steel (MSS) was studied. Experiments were carried out varying a broad spectrum of erosion parameters, including impact velocity, impact angle, and exposure duration. Both slurry and liquid impingement erosion were employed in the experiments, with testing conducted using both distilled water and saline solutions to assess the combined effects of corrosion and erosion wear. Compared to untreated samples, a significant improvement in the erosion wear resistance of AISI 420 MSS due to low-temperature plasma carburizing treatment was observed for all tested conditions. The observed performance enhancement can be attributed to the formation of the carburized layer, constituted of the α'C and Fe3C phases. Results also highlighted that the severity of the tribosystem was significantly influenced by the test solution characteristics. A marginal increase in severity was observed upon introducing the saline solution, while a more substantial severity increase occurred with the addition of solid particles in the test fluid. The specimens' mass loss was increased by increasing impact velocity, following a simple potential relationship, and with impact angle, following a first-degree linear equation. In the case of the exposure time, the mass loss curves depended on the test environment. For solutions containing quartz particles, an additional final stabilization stage was observed in addition to the acceleration stage observed in the absence of abrasive component. This phenomenon was attributed to surface work hardening induced by the impact of solid particles. Regarding wear mechanisms, samples tested only with distilled water displayed erosion flow marks. Those containing distilled water and NaCl exhibited not only flow marks but also pits. Lastly, solutions containing solid particles additionally presented features of plastic deformation, lip formation, craters, indentations, and extruded material.