Sliding wear performance in molten Zn–Al bath of cobalt-based overlayers produced by plasma-transferred arc weld-surfacing

The purpose of this investigation was to improve the wear resistance of part materials (bush and sleeve in sink roll) by applying plasma transferred arc (PTA) surfacing technique in the continuous hot-dip galvanizing facilities. Candidate alloys from the preliminary investigation were cobalt-based Stellite 6 and Tribaloy 800 with WC, WC–Co, TiC, NbC, and Cr3C2. The resultant deposits were subsequently characterized using X-ray diffraction, scanning electron microscopy, and the microhardness tests. Microstructural development during the solidification of each deposit is discussed. Pin-on-disk sliding wear tests were conducted in a molten Zn–0.18%Al (wt.%) bath at 470 °C to evaluate the wear performance of the PTA weld-surfaced cobalt-based alloys. Based on microstructural observation and the microhardness measurement, sliding wear performance of the PTA weld-surfaced cobalt-based alloys in molten Zn–Al bath is reported and compared with pin and disk combination.