Wear performance and microstructures of Fe-Cr-C alloy cladding on heterogeneous welded joints of NM450/ER70-G/ZG30SiMn

This work employed Fe-Cr-C alloy as the cladding material to fabricate wear-resistant coatings on dissimilar steel welded joints composed of NM450 wear-resistant steel and ZG30SiMn cast steel with ER70-G welding wire. The investigation focused on elucidating the effect of dilution ratio levels on microstructural distribution and wear behavior within this heterogeneous multi-material system. Owing to its inherently higher chromium (Cr) content, the NM450 region demonstrated more pronounced carbide formation compared to the ER70-G and ZG30SiMn regions. Microstructural analysis revealed that Cr7C3 carbides predominantly formed along grain boundaries, whereas Cr23C6 carbides mainly precipitated within grains. After cladding, the wear resistance of the NM450/ER70-G/ZG30SiMn welded joint was markedly improved, with the high-dilution coating exhibiting superior performance. This enhancement was attributed to favorable thermal conditions in the high-dilution scenario, promoting a more homogeneous precipitation of Cr23C6. Although significant elemental mixing occurred at the interfacial zones, the top region of the cladding layer remained minimally affected by dilution-induced drawbacks. Accordingly, the high-dilution sample demonstrated better wear resistance than its low-dilution counterpart due to optimized carbide precipitation characteristics. These findings provide basic insights for designing effective cladding strategies for complex multi-material components in demanding industrial applications.