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Laser Cladding of Nickel Based Carbide Dispersion Alloys for Hardfacing Applications
G.L. Goswami, Santosh Kumar, R. Galun and B.L. Mordike

High wear resistance from any surface generally requires a microstructure in which fine and hard particles are distributed randomly and uniformly in a ductile matrix. There can be many approaches to achieve such a microstructure, one attractive option is laser cladding of a mixture of fine and hard particles together with ductile alloy powder.

An attempt was made to develop cladding of nickel – chromium (ductile alloy powder) based WC and Cr2C3 (both of these are hard particles) dispersion alloys for hardfacing of 0.15% C-steel by blown powder laser cladding process. In these experiments Nickel-chromium alloy powders (Ni-20Cr) and carbide powders, in different proportions were mixed separately for cladding. Four compositions, (Ni-20Cr)-10Cr2C3, (Ni-20Cr)-10WC, (Ni-20Cr)-40Cr2C3 and (Ni-20Cr)-40WC have been cladded. The process parameters have been optimized to obtain defect free claddings. The cladded samples were characterized by optical microscopy, microhardness measurements across the substrate – clad layer interface and dry abrasion test by pin on disc method against 600 grit size SiC abrasive paper. Results were compared with stellite-6 hardfacing produced by same method. Nickel – Chromium alloys with 40% Cr2C3 showed slightly less hardness and much better wear resistance while that with 40% WC showed much lower hardness and still much better wear resistance when compared with stellite-6 claddings.

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