Study on the Particle Erosion Wear Behavior of TP347 Steel Under High-Temperature Conditions

To reveal the wear mechanisms of high-temperature metallic materials under particle erosion, this study investigated TP347 steel using a single-particle erosion–oxidation in situ system, off-axis digital holographic microscopy (DHM), granular erosion testing, and finite element modelling. Compared with conventional ex situ SEM or 3D profilometry, DHM provides crater-scale three-dimensional quantification of pit mouth diameter, crater depth, and crater volume. Under single-particle impact at 400 °C, the crater morphology changed from a wide and shallow profile at 30° to a deeper and more symmetric indentation at 90°, while the fitted velocity exponent increased from approximately 0.36 to 0.94 with increasing impact angle. Under normal impact, increasing the pre-oxidation temperature from 400 to 600 °C increased oxide-film thickness and crater depth and strengthened the velocity dependence of erosion. Granular erosion showed a staged process in which initial oxide-film removal was followed by a more stable substrate-involved erosion stage after the accumulated erodent mass approached 60 g. Finite element results reproduced the transition from tangential-shear-dominated damage at low angles to normal-impact-induced plastic indentation and oxide-film cracking at high angles. These results clarify the coupled role of impact angle, velocity, temperature, and oxide-film response in the high-temperature erosion behavior of TP347 steel.