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用金相、扫描和透射电镜研究了690合金经1450-1550℃,5 min熔本过热处理对合金再结晶组织和显微硬度的影响。结果表明,690合金中凝固析出的TiN的体积分数和平均尺寸随着熔体过热温度的升高而降低,其形态由规则的块状转变为颗粒状。经均匀化退火后,TiN的体积分数有所增加,而平均尺寸却有所降低。再结晶退火的过程中有大量亚微米尺度的Ti(C,N)弥散析出,其析出量随着熔体过热温度的升高而增加,这些细小的Ti(C,N)粒子可以起到沉淀强化的作用,提高690合金的显微硬度。
The effects of overheating the 690 alloy on the recrystallization microstructure and the microhardness of the alloy by 1450-1550 ℃ and 5 min were investigated by metallography, scanning and transmission electron microscopy. The results show that the volume fraction and the average size of TiN precipitated in 690 alloy decrease with the increase of the melt overheat temperature, and the morphology changes from regular bulk to granular. After homogenization annealing, TiN volume fraction increased, while the average size has decreased. In the process of recrystallization annealing, a large number of Ti (C, N) in the submicron scale are dispersed precipitously, and the amount of Ti (C, N) precipitates increases with the increase of the melt overheat temperature. These tiny Ti (C, N) Strengthen the role of improving the microhardness of 690 alloy.