P92钢高温持久强度试验后组织变化对性能的影响

采用扫描电镜和透射电镜对国产P92钢在600℃下经持久强度试验后的显微组织进行了观察，并研究了组织变化对性能的影响．结果表明：试验1429h前硬度下降主要是由于M23C6的粗化，而后由于大量Laves相析出产生的强化作用使硬度重新上升．当试验6063h后，Laves相粗化使强化效果减弱，硬度再次下降，此时MX仍然保持细小的尺寸，具有较好的强化效果．在整个持久试验过程中，板条马氏体的回复、再结晶导致的位错强化减弱，W、Mo从基体的脱溶导致的固溶强化减弱都对硬度下降起一定作用．

Effect of Microstructure Evolution on Property of P92 Steel During High-temperature Creep-Rupture Tests

The microstructure of domestic P92 steel was investigated by SEM and TEM during creep rup ture tests at 600 ~C, while the effect of microstructure evolution on its mechanical property analyzed. Re sults show that during the creeprupture tests, the hardness of P92 steel reduces before 1 429 h due to the coarsening of M23 C6, and increases later on resulting from the precipitation of a large amount of Laves phase. With the coarsening of Laves phase, the hardness reduces again after test duration of 6 063 h, when MX still keeps fine and has excellent precipitation strengthening effect. During the whole process of creep rupture test, the strengthening of dislocation and solid solution weakens due to both the recovery and re crystallization of lath martensite and the precipitation of Mo and W from the matrix.