Effect of laser surface cleaning on yellow brass: Application for cartridge case maintenance

In this study, the corrosion layer on the surface of yellow brass (or cartridge brass, C26800) was removed via the laser surface cleaning (LSC) process. Laser fluences of 0.51, 1.62, and 5.07 J/cm2 with different hatch distances were employed for corrosion removal, and the optimal LSC process was identified. It was found that the LSC process with large laser energy inputs (e.g., high laser fluences with small hatch distances) causes carbonization and deformation at the surface. However, the LSC processes with low laser energy inputs (e.g., low laser fluences with large hatch distances) retain the corrosion residues. The effects of the LSC process on the microstructure and mechanical properties of yellow brass were investigated. Voids and cracks occurred at the subsurface after the LSC process with a small hatch distance and high laser fluence. This microstructural deformation deteriorated the mechanical properties of yellow brass. By contrast, the optimal cleaning process effectively removed corrosion and resulted in marginal changes in the microstructure and mechanical properties of C26800. Finally, the optimal cleaning process was applied to the in-use 76 mm medium-sized caliber cartridge case maintenance, effectively removing the corrosion layer.