Effect of Combined Grinding-Burnishing Process on Surface Integrity, Tribological, and Corrosion Performance of Laser-Clad Stellite 21 Alloys

Herein, the influence of the grinding-burnishing on surface integrity, mechanical properties, and corrosion performance of Stellite 21 alloys coating deposited by laser cladding is investigated. The as-clad specimens are first ground followed by further modification by ball burnishing at forces of 424 N and 509 N. Results show that the grinding-burnishing enhances surface finish by lowering R-a from 2.6 to 0.73 mu m and R-z from 13 to 4.9 mu m, respectively. Surface porosity is found to decrease from 3.8% to 0.9%. Hardness is increased from 609 HV to 702 HV, with a surface alteration as deep as 250 mu m, while wear resistance increases by reducing worn volume from 4.15 to 2.95 mm(3). Because of high hardness, the grinding-burnishing increases impact resistance by lowering indent depth by 20%. Grains flatten and surface undulations are remarkably reduced due to burnishing. Finally, grinding-burnishing at 509 N improves the corrosion resistance by increasing positive corrosion potential from -0.41 to -0.14 V and lowering corrosion current density from 6.34 x 10(-4) A cm(-2) to 2.19 x 10(-5) A cm(-2), as compared to grinding. This synergistic grinding-burnishing can be a plausible post-treatment route for the laser-clad alloys.

Automated summary

In this study, the influence of grinding-burnishing on the surface integrity, mechanical properties, and corrosion performance of laser-clad Stellite 21 alloys coating was investigated. The results showed that grinding-burnishing improved surface finish, reduced surface porosity, increased hardness and wear resistance, and improved impact resistance. Burnishing also flattened grains and reduced surface undulations. Furthermore, grinding-burnishing at a force of 509 N improved corrosion resistance compared to grinding alone.