Corrosion and Tribological Behavior of Laser Processed 13Cr-4Ni and AISI 304 Stainless Steels
R. Singh and S.K. Tiwari
Laser cladding to improve the corrosion and cavitation resistance of stainless steels 13Cr-4Ni and AISI 304 was performed with a high power diode laser (HPDL) using Stellite powder. Dendrite and interdendrite microstructure was evolved with a significant compositional difference on the surface. In the interdendritic region, Co and Cr were found to change with increase in the HPDL energy density from 32 to 52 J/mm2. Increase in the hardness, by 2.5 to 3.0 times, was achieved after modifying the surface of 13Cr-4Ni and AISI 304. HPDL cladding could enhance the pitting resistance such that the pitting potential increased to as high as +379 mV from -41 mV and +244 mV for untreated 13Cr-4Ni and for AISI 304 stainless steel. Laser cladding reduced the mass loss due to cavitation erosion to 1 mg (at 32 J/mm2 HPDL energy density) from 79 and 136 mg for untreated 13Cr-4Ni and AISI 304 stainless steel in 3.5% NaCl solution.
Keywords: High power diode laser (HPDL), stainless steel, Stellite, laser cladding, coating, microstructure, corrosion, cavitation, microhardness surface engineering