The phase diagram of an Nb-and V-containing 18Mn18Cr0.5N steel was investigated using thermodynamic calculation.The compositions and characteristics of precipitates were investigated by scanning electron microscopy,energy dispersive spectrometry,X-ray diffraction,and differential scanning calorimetry.Under equilibrium conditions,MX precipitates at 1 350℃.MX is a substitutional solid solution of Nb4N3.38,and its composition(at.%)is approximately:Nb 40,N 40,V 8,and Fe,Cr,and Mn balance.The precipitates,with shapes including irregular bulk,rod,and ellipsoid,are primarily distributed at grain boundaries and triple junctions,and their size is approximately 5-10μm.Finally,the microalloying of high nitrogen CrMn austenite steels,control of precipitate size,and the effect of precipitate on hot forming were discussed. The phase diagram of an Nb-and V-containing 18Mn18Cr0.5N steel was investigated using thermodynamic calculation. Compositions and characteristics of precipitates were investigated by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and differential scanning calorimetry. Bunder equilibrium conditions, MX precipitates at 1 350 ° C.MX is a substitutional solid solution of Nb4N3.38, and its composition (at.%) is approximately: Nb 40, N 40, V 8, and Fe, Cr, and Mn balance. precipitates, with shapes including irregular bulk, rod, and ellipsoid, are distributed at grain boundaries and triple junctions, and their size is approximately 5-10 μm. Finaally, the microalloying of high nitrogen CrMn austenite steels, control of precipitate size, and the effect of precipitate on hot forming were discussed.