Effect of Siliceous Monel VKM1 Crystallization Conditions on Extruded Semi-Finished Product Structure

The effect of crystallization conditions (during casting in a copper chill mold, cast iron mold, and with ingot preparation by high-gradient directional crystallization) of high-strength deformable wear- and corrosionresistant alloy based on nickel-copper grade VKM1 (NMKZhMts-30-4-2-1-VI) on grain size in final semifinished product is studied, i.e., extruded bar with an identical heat treatment regime. It is shown that ingot casting in a cast iron mold provides preparation of a dense original ingot with coarse eutectic fragment precipitates that do not dissolve entirely on heating for extrusion, they initiate development of a considerable amount of slip planes during extrusion, and on quenching delay grain growth. This provides formation of a more fine-grained structure compared with metal cast in a copper chill mold and that obtained by high-gradient directional crystallization.