Erosion behaviour of Fe-Cr-C alloys: Cast alloy versus coating

Abstract

This research focuses on the erosion wear behaviour of two Fe-Cr-C alloys with similar chemical compositions obtained using different production methods. The first alloy belongs to the high chromium cast irons (HCCI). It was made by casting, after which the samples were heat treated by annealing. The second alloy in the form of the coating was applied by the plasma transferred arc (PTA) surface welding process at the substrate material (structural carbon steel). Damage to the components of industrial plants due to erosive and/or abrasive wear is a frequent cause of failure and outages of such systems. For this reason, and to bring the experimental research closer to real service conditions, an erosion test was performed at a gas blast sand facility with a high erodent speed of 90 m/s and a higher feed rate than standard erosion testing parameters recommended in ASTM G76 standard. Microstructural characterisation of all samples was done using a scanning electron microscope (SEM). The X-ray diffraction analysis (XRD) was used to identify the phases present. Similar erosion mechanisms were observed on all tested specimens, but coated samples (PTA alloy) had a lower mass loss during the erosion test compared to cast samples (HCCI alloy), i.e. they showed better erosion resistance.