Structural modification in a re-heated bead-overlapping zone of the multiple-pass plasma-transferred arc Fe-Cr-V-Mo-C coating

The structural evolution of the overlapping bead zone of Fe-Cr-V-Mo-C plasma-transferred arc (PTA) multiple-pass coating has been investigated. The overlapping bead 2-2.5 mm width zone experienced high-temperature re-heating from a successive bead deposition, which resulted in its structural evolution as compared to that of the previously deposited metal. At least three microstructurally different regions have been found inside the re-heated zone as follows: high-tempered region, eutectic carbide recrystallization region and incomplete melting region. These three structurally different regions were characterized by different microhardness and wear resistance levels. Basing upon the results of microstructural characterization, we offer schematics of the coating formation during deposition as well as discuss the role of microstructure in wear.