Sustainable hardfacing via gtaw powder pre-placement: in situ synthesis of multi-carbides from recycled WC/TIC inserts cermets

Abstract This study investigates a sustainable and cost-effective route for producing high performance hardfacing via Gas Tungsten Arc Welding (GTAW) using recycled cermet insert powders (WC/TiC). The primary objective was to conduct an exploratory feasibility analysis on the metallurgical transition of recycled feedstock into wear resistant coatings. The filler was deposited on a low carbon steel substrate, resulting in a high dilution rate of approximately 63%. Despite the dilution from the substrate, the weld metal exhibited superior mechanical performance with average hardness exceeding 1000 HV. This is attributed to the absence of iron in the recycled feedstock, unlike conventional filler metals that typically contain high iron concentrations, allowing the carbide forming elements to maintain a dominant reinforcement effect. This outcome is attributed to the strong reinforcement effect promoted by carbide forming elements, which effectively compensate for the substrate dilution. Microstructural analysis confirmed a complex multi carbide composite, including partially dissolved WC, stable TiC, and newly synthesized iron tungsten carbon ternary carbides (M6C and M3C). These findings validate the technical viability of upcycling discarded inserts into high performance feedstock, demonstrating their potential as versatile fluxes for hardfacing across others welding processes. This establishes a sustainable and effective route for producing durable overlays tailored for severe abrasive applications.