Experimental and numerical investigation into the stripping mechanism of Grade-A marine steel during high-pressure water jet impingement

This study investigated the removal behavior and stripping mechanisms of corrosion products during high-pressure water jet rust removal, using a two-component epoxy coating as a rust-layer substitute. Numerical simulations and impingement experiments under different jet pressures were combined to establish a water jet–Grade-A marine steel interaction model. High-speed photography, scanning electron microscopy, and confocal laser scanning microscopy were used to characterize the stripping process and surface morphology. Simulations showed that the maximum stress occurred at the edge of the liquid–solid contact region, where initial coating failure was also observed experimentally. The stripped area displayed a characteristic horseshoe-shaped morphology, mainly attributed to the horseshoe vortex formed during impingement. As the pressure increased, the removal morphology evolved from incomplete coating removal at 20–40 MPa to complete removal with substrate grooving at 60 MPa, and then to severe plastic deformation and extensive micro-pitting at 80–100 MPa. This study clarifies the failure mechanisms of high-pressure water jet rust removal, identifies the critical pressure range that balances removal efficiency and substrate integrity, and provides a theoretical basis for process optimization.