Effect of alloying elements on microstructure, wear, and corrosion behavior of Fe-based hardfacing

Iron-based hardfacing alloys are commonly used to combat severe wear in steel, mining, and mineral industries. However, these are often subjected to a moist and corrosive environment along with a high degree of wear and abrasion. This paper presents a systematic study on the effect of composition on microstructure, wear resistance, and corrosion resistance of four iron-based hardfacings of systematically designed alloy compositions. It is shown that during the hardfacing process, alloy composition dictates the constituent phases as well as the extent of microstructural refinement. It is observed that the addition of secondary carbide-forming elements like Nb and Mo can enhance both wear and corrosion resistance. Furthermore, an iron-based hardfacing comprising of 36 Cr-4.3 Nb-1.5 Mo-0.3 N-4.1 C exhibited the best combination of hardness, wear, and corrosion resistance due to the synergistic effect of primary carbide, secondary carbides, and carbo-nitrides of sub-micron size rendering the matrix richer in Cr and inherent effect of molybdenum and nitrogen for corrosion protection in Cr rich alloys. This hardfacing alloy is expected to enhance the service life of critical components in process industries exposed to wear and corrosion and can pave way for new alloy designs for Fe-based hardfacings.