The precipitation behavior of nitro-carbides in 18Mn-4Cr-0.4C-0.1N non-magnetic steel during isothermal ageing with a range of 800~950 ℃ was investigated by metallography,X-ray diffractometry(XRD) and electron probe microanalyzer(EPMA),and the isothermal precipitation-dissolution kinetic curves of nitro-carbides were established.The results show that the M23(C,N)6 and M7(C,N)3 phases of nitro-carbides are precipitated along austenitic grain boundary.With increasing the holding time,the amount of precipitate...