The Nb-V-Ti-N-C System Microelements Coupling Precipitation Behavior and Its Effects on Properties in High Strength Naval Steel

The Nb-V-Ti-N-C system microelements coupling precipitation behavior in high strength naval steel was thermodynamically analyzed. effects of micron/nano particles on the microstructure, mechanical properties, and corrosion resistance were also studied by an situ scanning electron microscopy (SEM) tensile test, transmission (TEM) analysis, electrochemical polarization measurements. results show that solid solution amount Nb, V, Ti, N, or C decreases steels as temperature decreases. Carbonitrides begin to precipitate at 1506.39 °C N1 steel, carbonitrides are nano-scale. Meanwhile, 1628.74 N2 which is 116.69 higher than corresponding liquidus 1512.05 °C; with micron scale formed metal melt. test revealed increase titanium content from 0.05% 0.1%, increases while elongation SEM indicated lower plasticity associated micron-scale, micro crack sources under stress. Polarization pitting may easily occur abnormally large-sized (Nb, Ti)(C, N) carbonitrides.