Improvement of corrosion resistance of materials used in drinking water systems by laser surface melting

Abstract

Copper alloys and stainless steels are materials commonly used in drinking water systems as piping materials and accessories. To minimize contamination arising from corrosion and to prolong the service life, laser surface melting (LSM) of brass, bronze, stainless steels S304 and S316 was attempted using a 2 kW CW Nd:YAG laser. The corrosion resistance before and after LSM was determined by the polarization test. The corrosion resistance was increased by a factor ranging from 2.7 to 8.0. The microstructures of the laser-melted specimens were studied by scanning electron microscopy (SEM). The morphology of the laser-treated specimens after the polarization test was studied by SEM. The increase in corrosion resistance could be attributed to refmement in the microstructure.Copper alloys and stainless steels are materials commonly used in drinking water systems as piping materials and accessories. To minimize contamination arising from corrosion and to prolong the service life, laser surface melting (LSM) of brass, bronze, stainless steels S304 and S316 was attempted using a 2 kW CW Nd:YAG laser. The corrosion resistance before and after LSM was determined by the polarization test. The corrosion resistance was increased by a factor ranging from 2.7 to 8.0. The microstructures of the laser-melted specimens were studied by scanning electron microscopy (SEM). The morphology of the laser-treated specimens after the polarization test was studied by SEM. The increase in corrosion resistance could be attributed to refmement in the microstructure.