Pulsed current plasma transferred arc hardfacing

摘要

Hardfacing is used to enhance surface properties of a metallic component, as a specially designed alloy is surface welded to achieve specific wear properties. Surface properties and quality depend upon the selected alloy and welding process. Powder feeding plasma transferred arc (PTA) allows for homogeneous refined micro structure, low distortion and dilution, resulting on enhanced surface properties when compared to hardfaced deposits processed with other welding techniques. This work evaluates the effect of pulsed current on an high carbon cobalt alloy deposited by PTA on carbon and stainless steel. Results showed that the use of pulsed current leads to a finer microstructure, higher hardness and lower dilution. The role of the substrate steel depends on the set of processing parameters used but for a same set of parameters it determines microstructural features of the coatings.