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通过对材料性能、金相、扫描电镜(scanning electronmicroscope,SEM)、能谱(energy disperse spectrum,EDS)、氧化皮、碳化物萃取、透射电镜(transmission electronmicroscope,TEM)等的分析,对在超超临界机组运行5 400和25000h的新型奥氏体耐热钢HR3C进行老化研究,经研究表明HR3C运行25000h后性能的变化主要表现为向火侧室温抗拉强度上升4%,屈服强度下降10%;650℃拉伸性能略有下降;压扁时有脆化,硬度明显提高,表明已发生时效强化;内外壁氧化皮形成致密的Cr2O3层;组织无明显老化,析出物主要为Z相、M23C6和M6C型,碳化物沿晶界较明显析出;运行25000h后析出的碳化物中M6C和M23C6含量明显高于运行5 400 h后析出的含量,表明已有M23C6型碳化物向M6C型碳化物过渡。
Through the analysis of material properties, metallographic, scanning electron microscopy (SEM), energy disperse spectrum (EDS), scale, carbide extraction, transmission electron microscopy (TEM) The results show that the HR3C performance of HR3C after 25000h operation is mainly increased by 4% tensile strength and 10% lower yield strength at room temperature. Tensile properties at 650 ℃ slightly decreased; when crushed, there was embrittlement and the hardness increased obviously, indicating that the aging strengthened; the Cr2O3 layer formed on the inner and outer walls of the skin; There was no obvious aging of the tissue, the precipitates were mainly Z phase, M23C6 and M6C and carbides are obviously precipitated along the grain boundaries. The contents of M6C and M23C6 in carbides precipitated after 25000h operation are obviously higher than those precipitated after 5 400 h operation, indicating that M23C6 carbides have transitioned to M6C carbides.