Microstructure and wear characteristics of high-carbon Cr-based alloy claddings formed by gas tungsten arc welding (GTAW)

High-carbon Cr-based alloy claddings with distinct carbon contents are fabricated on medium-carbon steel substrates by the GTAW process utilizing various pure Cr and CrC (Cr:C = 4:1) alloy fillers. The results show that the microstructures of hypoeutectic, near-eutectic, and hypereutectic structures with various pro-eutectic Cr–Fe phases, (Cr,Fe)23 C6 and (Cr,Fe)7 C3 carbides, form in the coated surface depending on the carbon contents. The wear resistance is determined by the type, mechanical properties, and volume fraction of pro-eutectic phases, as well as by the matrix microstructure. The cladding with 2.3%C possesses the worst wear resistance, which can be attributed to great amounts of soft pro-eutectic Cr–Fe phases. The cladding with 5.9%C has the best wear resistance. The improvement of wear resistance results from the high volume fraction of hard and wear-resistant pro-eutectic (Cr,Fe)7 C3 carbides, which are distributed homogeneously in the fine and strong [α + (Cr,Fe)7 C3] eutectic colonies.