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用扫描电镜(SEM)、背散射电子显微镜(EBSD)及X射线衍射(XRD)等方法对不同运行阶段的T91钢管受热面析出碳化物颗粒度、亚结构及位错密度进行了定量测试分析。研究结果表明,在运行前期,随着组织老化程度的增加,T91钢析出碳化物颗粒的数量呈现出明显的上升趋势,运行后期到寿命末期(爆管失效),碳化物颗粒出现明显的聚集长大;T91钢运行前期位错密度下降明显,伴随着前期位错运动的结果是亚结构出现初期兼并,促成亚结构略有粗化;运行后期到失效阶段,T91钢位错密度基本上趋于稳定,亚结构快速兼并,亚晶界密度显著减少。
The grain size, substructure and dislocation density of carbide precipitated on the heating surface of T91 steel tube in different operation stages were quantitatively analyzed by SEM, EBSD and XRD. The results show that in the early stage of operation, the amount of carbide particles precipitated in T91 steel shows a clear upward trend with the increase of the aging degree. During the later period of operation to the end of life (tube explosion failure), the carbide particles show obvious aggregation length The dislocation density of T91 steel decreased obviously at the early stage of operation, with the result of the early dislocation movement, the sub-structure was initially merged, which resulted in a slight coarsening of the sub-structure. During the later stage of operation to the failure stage, the dislocation density of T91 steel tended to be basically Stable, rapid sub-structure merger, subgrain density significantly reduced.