Nitriding of Molten Chromium-Manganese Steels

Resumo

Theoretical and experimental studies are conducted in the field of nitriding high strength nonmagnetic steels. Temperature-time correlation of the degree nitrogen assimilation and nitrogen content in steel 04Cr20Ni6Mn11Mo2NVNb in the case of alloying with nitrogencontaining manganese and chromium ferroalloys in air and during purging with nitrogen are determined by experiment. Gas phase nitriding of this steel is possible at 1450 °C during 30 min reaching a nitrogen content of 0.42%. A twostage process for lowcost nitriding is developed. In the first stage melts are purged with highpurity nitrogen to reach a nitrogen content of 0.25–0.30%. In the second stage powder alloying additions are injected into a stream of nitrogen with a melt temperature as low as possible.