国产T23钢高温组织演变及其对性能的影响

 通过对国产T23钢550 ℃、600 ℃和650 ℃的持久试样显微组织的分析，研究了T23钢高温蠕变过程中的组织演变及其对性能的影响。结果表明，在高温蠕变过程中，T23钢贝氏体铁素体基体和小岛中的马氏体将发生回复和再结晶，位错密度下降，M23C6碳化物不断粗化，并且有少量M23C6转变为M6C。蠕变断裂时间较短时，M23C6碳化物粗化对性能下降起主要作用，随蠕变断裂时间延长，贝氏体铁素体基体和小岛中马氏体的回复、再结晶对性能下降的影响增大。温度较高时，回复及再结晶开始较早，对性能下降的影响提前。650 ℃时，T23钢的组织演变和性能下降过快，应尽量避免在此温度下使用。

Effect of Microstructure Evolution During Creep on Properties of Domestic-Made T23 Steel

Creep rupture specimens were chosen to study the effect of microstructural evolution at 550 ℃, 600 ℃ and 650 ℃ on the properties of domestic made T23 steel. During creep, dislocation density decreases due to the recovery and recrystallization of the bainitic ferrite matrix and the martensite in the prior austenite small island, and M23C6 carbides coarsen gradually, even a few M23C6 carbides are transformed to M6C. For the short creep rupture time, the coarsening of M23C6 type carbide plays a main role in property degradation. As the long creep rupture time, the effect of recovery and recrystallization of the bainitic ferrite matrix and martensite in the small island increases. At higher temperature, the earlier recovery and recrystallization begin, and their effect on property degradation will be produced in advance. It is suggested that domestic made T23 steel should be avoided to use at 650 ℃, since the microstructural evolution and property degradation are too fast.