INFLUENCE OF LASER CLADDING ON.SS3O4L PLATE USING POWDERS

Abstract

The wear resistance of engineering components encountering the attack of erosive and abrasive environment during operation can be improved by hard facing on their surface with optimum techniques of laser cladding. The microstructure, erosion, abrasion of Mo, Cr3C2 and WC coating were investigated experimentally by using X-ray diffraction, optical microscopy, scanning electron microscopy, vicker microhardness (HV.2), slurry erosion pot tester, pin-on-disc wear test. Coating were manufactured by laser cladding on an AISI 3 04L stainless steel substrate using a 10kw continues wave CO2 laser. Coatings were metallurgical bonded to the substrate. The partial dissolution of Cr3C2 particles in the melted pool leads to carbon and chromium enrichment in the matrix and hence causes the formation of much CrrC3i M23C6 in solidifying structure. The WC particle is uniformly distributed in coating; the microscopic morphology and distribution• of WC particles were characterized by scanning electron microscopy. In Mo coating hard brittle carbide M7C3 was formed due to the rapid solidification of alloy molten pool. The observed microhardness of WC coating was 850-900 HV, Mo was 1150-1200 HV and Cr3C2 was 800-850 HV. The Mo, Cr3C2 and WC coating were subjected to sliding wear against grade 400-grits SiC abrasive waterproof grinding paper counter bodies under dry environment. A pin-on-disc type apparatus was used with normal load of 20N and sliding distance 300m. It was demonstrated that the coating sample under dry condition had higher wear resistance than substrate. Several wear failure mechanisms such as local plastic deformation, cracks, pits, and debris were identifying after the test. In the erosion testing, the erosive environment was selected as quartz sand slurry. This report summarized the possible reason of the erosion. Generally, coatings such as Cr3C2and WC have improved erosion resistance but Mo coating could not improved erosion resistance.