Abstract
<jats:p>Introduction. The surface properties of machine parts and tools play a significant role in their performance when the interactive mechanical action on the metal surface leads to wear. Modifying the surface properties of components is essential, particularly in critical industrial applications. Surface properties such as hardness and wear resistance of a metallic material can be primarily enhanced either by introducing a new phase or element into the surface layer, or by surface treatment (e.g., laser, plasma, or electron beam) of the base material to develop the desired phases within the matrix. Gas tungsten arc welding (GTAW) offers several advantages over other methods, primarily in terms of precision, speed, and versatility at a relatively low cost. Technically, it is capable of alloying the metal surface more quickly and uniformly compared to conventional carburizing and nitriding processes. During arc heating, the surface is modified by melting a paste or coating pre-applied to the substrate through the rapid application of intense arc heat. This results in a steep thermal gradient accompanied by high heating and cooling rates, similar to the principles of laser and electron beam cladding. The objective of the present study is to evaluate the feasibility of surface alloying of low-carbon steel with the Fe–C–Cr system using gas tungsten arc welding (GTAW). Methods. The paper examines low-carbon steels using St3 steel as an example. The steel served as the substrate and was coated with a layer (≤1 mm thick) in experiments employing the Fe–C–Cr surface alloying method via GTAW. A powder mixture of Fe and Cr₂O₃ was used as the coating alloy, with a particle size of 45 μm. The samples were examined using optical and electron microscopy, as well as X-ray diffraction. Abrasion resistance tests were also conducted. Results and discussion. Our research has shown that during gas tungsten arc welding (GTAW), when melting a Fe–C–Cr paste, the shape and size of the fusion zone (FZ) on the steel surface are determined by arc parameters such as current, voltage, and travel speed, while the molten metal pool is protected from atmospheric contamination by an inert argon shielding gas. Adding carbon dioxide to the shielding gas increases the arc's heat input. To produce a series of hypereutectic hardfaced surface layers using the Fe–C–Cr system, paste variants with varying carbon and chromium contents were developed to study their microstructure, wear resistance, and wear mechanism. Positive results were obtained, demonstrating a two- to three-fold increase in abrasive wear resistance.</jats:p>