高温时效对铁素体不锈钢组织和性能的影响

通过金相、SEM和EDS等技术，研究了900 ℃下不同时效时间对超纯铁素体不锈钢组织和性能的影响。结果表明，439钢种高温时效对Ti(C,N)析出作用较小，晶界析出相TiN较少，晶粒粗化严重，塑性较低；441钢种高温时效会沿着晶界析出Fe2Nb(Laves)相，析出数量较多，晶粒较细小，但由于Fe2Nb(Laves)相沿晶界呈网状分布，对材料塑性影响较大；444钢种高温时效会在晶界和晶内析出Fe3(Nb,Mo)3C，析出数量较少，第二相钉扎作用较弱，部分晶粒出现异常长大，由于Fe3(Nb,Mo)3C析出相未呈网状分布，断后伸长率高于441钢种。

Effect of high temperature aging on microstructure and properties of ferritic stainless steel

The effect of aging time on the microstructure and properties of ultra pure ferritic stainless steel at 900 ℃ was discussed by using metallographic, SEM and EDS. The results showed that 439 high temperature aging had little effect on the Ti(C,N) precipitation and the TiN phase precipitated at grain boundary was less, which caused serious grain coarsening and lower ductility. For 441 high temperature aging, Fe2Nb (Laves) phase was precipitated along the grain boundary. And the precipitation quantity was large, the grain size was small. The network Fe2Nb(Laves) distribution had a significant impact on the ductility. For 444 high temperature aging, Fe3(Nb,Mo)3C was precipitated in grain boundary and crystal. The little amount of precipitation caused the weaker second phase pinning effect and some grains grew abnormally. As a result of the precipitation Fe3(Nb,Mo)3C without mesh distribution, the ductility was higher than that of 441.