Impact-abrasive wear of martensitic steels and complex iron-based hardfacing alloys

Abstract

Highly loaded wear components in manifold applications such as sieves, crushers, etc. suffer from combined impact and abrasive wear. To gain deeper understanding of different ongoing mechanisms, four different Fe-based materials, two martensitic steels Hardox 450 and Hardox 600, and two gas metal arc welded (GMAW) hardfacings - a Fe–Cr–C based hardfacing and a complex-alloyed Fe–Cr–Nb–C–B alloy were investigated with a novel modification of a cyclic impact and abrasion test. This test rig uses quartz sand as abrasive and a plunger simulating industrial sieving applications. Pre- and post-test materials analyses were performed utilising 3D microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD), microhardness and nanoindentation tests for a thorough materials analysis and the clarification of the main occurring damaging mechanisms.Results indicate a very beneficial performance of a complex-alloyed Fe–Cr–Nb–C–B alloy due to its fine-dispersed hard phases and their homogenous distribution throughout the material, which does not change much with varying deposition parameters. In comparison, higher wear rates of a hypereutectic Fe–Cr–C alloy are attributed to coarse precipitated Cr-carbides within the microstructure. At martensitic steels, mechanically mixed layer were formed in the impact-abrasion region, which decreases the wear attack to a certain extent. However, massive materials displacement and abrasive wear occurs due to the lack of hard phases and high ductility, which obstruct increased abrasive attack.