Surface Alloying of Internal Surfaces of Low‐Carbon Steel Castings through Incorporation of Nickel, Nickel and Chromium, and 316L Stainless Steel Powders to Mold and Core Surfaces

A surface alloying technique is developed to enrich the internal surfaces of low‐carbon steel casting with nickel or and chromium. This unique involves incorporation (Ni), chromium (Ni + Cr), stainless (SS) powders into a slurry, then applying slurry onto cores used in sand molds which comes contact molten metal during casting. Various properties, including coating thickness, composition, microstructural phases, hardness, corrosion resistance surface‐alloyed layer, are studied. The substrate enriched chromium, up 16.32 wt% Ni 7.79 15.85 Cr. Optical microscopy shows that surface‐enriched layer continuous over entire ranges thickness from 229 1342 μm. When alloyed SS powders, layers demonstrate dendritic solidification microstructure, suggesting complete dissolution followed by solidification. While primarily displays pearlitic ferritic structures, simulation X‐ray diffraction confirm presence austenite ferrite when Cr used. Microhardness testing studies show significant improvement after alloying.