Influence of microstructure on slurry erosive wear characteristics of laser surface alloyed 13Cr-4Ni steel

The significance and effect of microstructure and hardness on the slurry erosion rates of laser surface modified 13Cr-4Ni steel are discussed in this paper. Commercial Stellite 6 and Colmonoy 88 powders were deposited on 13Cr-4Ni steel using two stage processes of laser surface alloying (LSA). Series of slurry erosive wear tests have been conducted on 13Cr-4Ni steel and LSA deposits by varying angles of impingement for a constant slurry velocity and also at different slurry velocities for two different angles of impingements. Characterization of deposits have revealed that the presence of hard complex secondary phases, which in turn have lead to 1.5-2-fold enhancement of surface hardness of LSA deposits. The erosive wear rates of LSA deposits are found to be increased linearly with angle of impingement and also showed power law character with slurry velocity. Colmonoy 88 deposits showed at least two-fold decrease in erosion rates when compared to 13Cr-4Ni steel for all test conditions. It is found that micro cutting and deep crater formation are the two main material removal mechanisms for substrate and Stellite 6 deposits, whereas progressive fracturing of secondary phases along with deep crater formation are instrumental in Colmonoy 88 deposits. (C) 2009 Elsevier B.V. All rights reserved.