【摘要】 采用金相显微镜、扫描电镜、透射电镜等手段考察了不同运行阶段12%Cr钢高温螺栓的微观组织变化。经与新螺栓对比,结果表明受检螺栓的组织中,局部区域δ铁素体含量超过10%。螺栓运行6万h后,其金相组织逐渐老化,碳化物沿δ铁素体边界析出,合金元素开始向碳化物迁移,材料进入老化初期;运行35万h后,碳化物颗粒粗化更加明显,沿δ铁素体边界已形成粗大的碳化物链,合金元素向碳化物中迁移严重,材料进入老化后期。更多还原

【Abstract】 By adopting means,such as metallographic microscope,scanning electron microscope,and transmitting electron microscope etc.,the microstructure variation of high-temperature bolts made from 12%Cr steel has been investigated.Through comparison with that of the new bolts,the results show that the δferrite content in some localities of structure for the investigated bolts has been over 10%.After the bolt being in operation for 60-thousand hours,its metallographic structure has gradually aged,the carbides being separated out along the boundaries of δ ferrite,the alloy elements start migrating to the carbides,the material entered into initial period of aging;after being in operation for 350-thousand hours,the coarsening of carbide particles being more remarkable,chains of rough and large carbides have been formed along the boundaries of δ ferrite,the material has already entered into the final stage of aging.更多还原