Blast furnace blow moulds - having a nickel based and ceramic layered coating to improve lifetime

摘要

The mould is first shot blasted for a height of 250 mm externally and 150 mm internally from the lip, both to clean and provide a roughened surface. A nickel bearing alloy such as Ni 20% Al; Ni 20% Cr; Ni 15% Cr 20% Fe, is then flame sprayed in thin layers to a depth of about 0.35 mm, while maintaining the preheated mould temp. to below 120 degrees C. Layers of a high m.pt. ceramic, e.g. Zr, Hf, Th, Mg oxides, Ti or W carbides, W or Mo silicides is then plasma sprayed to a depth of 0.7 mm again maintaining the mould temp to 100 degrees C.