Characteristics of Single-Track and Multi-track Depositions of Stellite by Micro-plasma Transferred Arc Powder Deposition Process

This paper describes the characteristics study of single-track and multi-track deposition of Stellite 6 on AISI 4130 steel substrate by indigenously developed micro-plasma transferred arc powder deposition (μ-PTAPD) process. Deposition height and width, dilution and microstructure have been used to characterize the single-track depositions by studying effects of micro-plasma power, travel speed of worktable and powder mass flow rate on energy consumption per unit traverse length and power consumption per unit powder mass flow rate. Micro-plasma power was found to be the most influential parameter that affects energy and deposition material consumption. Consequently, its influence on micro-hardness and abrasion resistance of multi-track deposition was studied. Results showed that increase in micro-plasma power decreases micro-hardness and scratch hardness number and increases mean value of friction coefficient. Comparison of microstructure and chemical composition of single-track and multi-track depositions revealed that single-track has finer dendritic microstructure than the multi-track deposition. The black colored matrix and white colored dendrites present in the multi-track deposition have higher wt.% of cobalt and less wt.% of chromium than the single-track deposition. Comparison of µ-PTAPD process capabilities with the existing processes for Stellite deposition establishes that it is an energy-efficient, cost-effective and good quality deposition yielding process.