【摘要】 采用金相组织分析、X射线衍射、电子探针显微分析等方法,研究了18Mn-4Cr-0.4C-0.1N无磁钢在800~950℃区间等温时效过程中氮碳化物的析出行为,并建立了氮碳化物的等温析出-溶解动力学曲线。结果表明,氮碳化物析出相M23(C,N)6和M7(C,N)3在奥氏体晶界析出,随着等温时间增加,析出数量增多,由粒状向链状聚集;进一步延长等温时间,两种析出相均发生分解,回溶到奥氏体中。M23(C,N)6和M7(C,N)3等温析出和分解的临界温度均为900℃,控制析出的临界冷却速度为25℃/m in。更多还原

【Abstract】 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 precipitated nitro-carbides increases and the carbides are congregated from discontinuous granular to chain.The two precipitation nitro-carbides are dissolved into austenite with further increasing the holding time.The critical temperature of isothermal precipitation and dissolution of M23(C,N)6 and M7(C,N)3 phases are 900 ℃,and their critical cooling rate of disprecipitation is 25 ℃/min.更多还原