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运用TEM和EDS等测试方法，对高铌X80管线钢连铸过程微合金元素的析出行为进行研究。结果表明：铸坯凝固冷却至1100℃时，存在片层状以及棒状析出物，此类析出物为Nb（C，N）碳氮化物，同时存在一些TiN析出物。当铸坯冷却至900℃时，开始出现中心富钛、边部富铌的（Nb，Ti）（C，N）星形和枝晶形碳氮化物。当铸坯冷却至750℃时，枝晶状析出物增多，同时也存在部分富铌的枝晶状Nb（C，N）碳氮化物。冷却至室温的铸坯晶界上存在大量的枝晶状析出物。由热力学计算和试验结果得出，对于高铌X80管线钢，枝晶状复合析出物开始析出温度介于1000~1100℃之间。

The precipitation behaviors of microalloy elements in high niobium X80 pipeline steels during continuous casting were investigated by using TEM and EDS. The results show that: when the casting slab steel cooling down to 1100℃, the morphology of Nb(C,N) carbonitrides in the slab steel are lamellar structure and rodlike, and the TiN precipitates also exist in the slab steel. When the casting slab steel cooling down to 900℃, the (Nb,Ti)(C,N) carbonitrides with have morphology of starlike and dendritic in the slab steel begin to appear, these carbonitrides are Tirich in the central and Nbrich in the caps. When the casting slab steel cooling down to 750℃, the dendritic precipitates begin to increase, and there are also have some dendritic Nbrich Nb(C,N) carbonitrides in the slab steel. There have a lot of dendritic carbonitrides in the grain boundaries when the casting slab steel cooling down to the room temperature. According to the thermodynamic calculation and experimental results, as for the high niobium X80 pipeline steel, the dendritics carbonitrides will be appeared when the casting slab steel cooling down to the temperature of 10001100℃.