Abrasive wear characteristics and microstructure of Fe-based overlaid ploughshares in different field conditions

Abstract In the present research, two different Fe-based claddings, namely SZ (Fe–Cr, Fe–33.37Cr–3.83C) and ZK (Fe–Mo, Fe–8.18Mo–4.5Cr–0.65C) were overlaid on EN-42 steel substrate by Manual Metal Arc Welding (MMAW) process with an aim to enhance the abrasive wear characteristics of the steel. The microstructural and abrasive wear behavior of overlaid samples was investigated in comparison with bare steel (EN-42) in actual field conditions at two different moisture levels (0–3% and 14–17%). Optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD), and hardness testing were performed to characterize the microstructural and mechanical properties of bare and overlaid steel samples. The effect of moisture content on abrasive wear resistance of tillage tools and tillage quality has also been evaluated. The results revealed that the variables such as carbide shape, size, distribution, and matrix structure of hardfacing influence the wear resistance of hardfacings. The SZ alloy showed higher abrasive wear resistance than ZK alloy due to the formation of M23C6 and M7C3 carbides in the hardfaced layer. The moisture content of the soil also affected the abrasive wear resistance of the substrate and different hardfacings materials, which in turn influence the tillage efficiency of the tool. The wear rate of bare and overlaid ploughshares is almost 3 times higher in dry field conditions (0-3% moisture) as compared to moist conditions (14–17%). The wear resistance indices (WRI) for SZ and ZK overlaying were found to be 1.85 and 1.48 respectively for low moisture conditions, and 1.9 and 1.54 for the moist condition.