Effect of Filter Coating on the Quasi‐ S tatic and Cyclic Mechanical Properties of a G42 C r M o4 Casting

In this paper, the effect of a mullite coating on a carbon‐bonded alumina filter used in steel melt filtration on the mechanical properties of the cast steel G42CrMo4 (1.7231) at both quasi‐static and cyclic loading is presented. The investigations cover quasi‐static tensile tests at different temperatures. Additionally, cyclic tests in high‐cycle fatigue (HCF) and very high‐cycle fatigue (VHCF) regimes were performed. Fracture surfaces as well as cross‐sections are examined by scanning electron microscopy and light microscopy to determine the non‐metallic inclusions responsible for failure. In comparison to the uncoated filter, a mullite coating on the filter leads to a deterioration of deformation characteristics and fatigue lifetime of the cast steel. This effect is attributed to a higher amount of large non‐metallic inclusions, which were not retained by the coated metal melt filter.