Mechanism of material removal and experimental investigation on electrolyte plasma polishing of high-strength steel

Artillery barrel rifling, being a typical complex structure characterized by deep holes and non-circular cross-sections, has long suffered from limited geometric accessibility and inadequate uniformity in finishing when using traditional mechanical techniques. The present work investigates the viability of electrolyte plasma polishing (EPP) for finishing high-strength steel (the material used in artillery barrels), intending to furnish theoretical support and parametric guidance for future application to real barrel parts. On the mechanistic and modeling side, the present study developed a multi-physics simulation framework that couples gas-liquid bubbly flow, tertiary current distribution, and electromagnetic fields. This framework enabled, for the first time, quantitative description of the anodic gas-layer evolution (void fraction rising from 0.0695% to 0.439%) and the “peak-shaving” dynamics (peak displacement of 4.49 μm) during EPP. It further uncovered a three-stage removal mechanism—starting with electrochemical dissolution, followed by bubble collapse impact, and ending with plasma-assisted synergistic removal—and clarified that the dynamic oxidation-removal equilibrium serves as the key to achieving surface leveling. In terms of processing effectiveness, EPP treatment reduced the surface roughness Ra of the artillery barrel steel samples from 2.833 μm to 0.778 μm, corresponding to a 72.5% decrease. The deformed layer (approximately 2–5 μm thick) generated by prior machining was entirely eliminated, without introducing a heat-affected zone, microcracks, or grain-boundary deterioration, thereby markedly enhancing surface integrity. Overall, the developed multi-physics model exhibits excellent agreement with experimental findings, which validates the potential of EPP for finishing complex-geometry areas and offers both theoretical backing and empirical data for the adoption of non-contact precision polishing in artillery barrel production.