A new processing technique produces high carbon-high nitrogen iron alloys by melting iron-carbon steels in a hot isostatic pressing (HIP) furnace with nitrogen as the pressurizing gas. Furnace cooling O-1 tool steel with enhanced nitrogen concentrations resulted in the retention of the austenite phase without formation of carbide and nitride precipitates. The duplex austenite/ferrite structure has enhanced hardness, strength, and wear resistance.