国产T91钢管蠕变脆性倾向的微观结构

Tendency of Creep Bittless of Domestic T91 Steel Tube From its Microstructure

业已证实，国产T91钢管存在着蠕变脆性倾向，采用TEM和SEM观察方法，对蠕变断裂后的残样进行了微观结构分析，研究成果表明．国产T91钢管的蠕变脆性倾向和可动位错密度的降低，碳化物的祖化和Sb、Bi等有害元素在晶界上偏聚有关。低应力长期蠕变破坏是晶界上的空洞串和微裂纹为主引致的晶间断裂。

It has been already verified that the dcmestic T91 stedl tube is subject oreep bittleness tendency. This paper rpplies tho TEM rnd SEM observation methods to make a microstructural analysis of the residual sample. The research results indicate that the creep bittleness tendency of dsmestic T91 steel tube is related to the reduction of slioing dislocrtion density, ccrrsening of carbide, and biased accumulation of etrimental elements such Sb, Bi, etc.on the grain mark, Long-term low-stress creep damage is intercrystalliee rupture mainly resulted from cavity sering and micoro-crack on the grain mark.