Mechanical properties of iron and steel with dispersed vanadium and niobium nitrides

Abstract

1. The addition of nitrogen, niobium, and vanadium to iron increased the strength and raised the ductilebrittle temperature. Precipitation of nitride phases during aging leads to further increase of the strength, but far greater embrittlement. 2. With a ferritic-pearlitic structure (Fe-C-MN system) the addition of nitrides also leads to an increase in strength and of the ductile-brittle temperature, but considerably less than in the Fe-MN system, which is explained by grain refining. 3. With a structure of temper martensite (Fe-C-Si-Mn-MN system) the increase in the strength is still smaller, and the ductile-brittle temperature decreases due to grain refining. 4. In both cases — the strength and the ductile-brittle temperature — the addition of vanadium nitride is more effective than niobium nitride at the same volume percentage.