Study of the operational parameters of plasma transferred arc melting and modelling of the process

Plasma transferred arc ( PTA) melting/ alloying technique can be successfully used in various surface modification applications and has the potential for industrial use, replacing other more expensive techniques such as laser or electron beam. Such applications require tight control of the process parameters. There is a restricted field of PTA parameter values, where PTA melting can be successfully performed with smooth and unoxidised surfaces. The heat source efficiency of PTA treatment is strongly affected by welding current, arc length and travel speed of the arc and it takes values between 0.40 and 0.55, while melting efficiency takes values between 0.05 and 0.25, affected by the same parameters as arc efficiency. The microstructure and hardness of the melting zone of a PTA pass is associated with heat input and arc length.