18Cr-9Ni-3Cu钢长期服役后σ相析出行为研究  

Analysis on σ Phase Precipitation of 18Cr-9Ni-3Cu after Long-term Services

作　　者：刘立民[1] 魏力民[1,2] LIU Limin;WEI Limin(Material Research Institute of Harbin Boiler Co.,Ltd.,Harbin 150046,China;State Key Laboratory of Efficient and Clean Coal-fired Utility Boilers,Harbin 150046,China)

机构地区：[1]哈尔滨锅炉厂有限责任公司,哈尔滨150046 [2]高效清洁燃煤电站锅炉国家重点实验室,哈尔滨150046

出　　处：《机械工程师》2019年第10期84-88,共5页Mechanical Engineer

摘　　要：利用光学显微镜、扫描电子显微镜、能谱检测和透射电子显微镜研究了18Cr-9Ni-3Cu钢在超超临界机组服役5×104h后σ相析出行为,理论方法探究了σ相析出与服役时间的关系、影响σ相析出的因素,并评估了σ相演化对蠕变强度的影响。结果表明:服役后18Cr-9Ni-3Cu钢主要析出物为MC、σ相及富Cu相,其中MC在晶界呈颗粒状析出,σ相在晶界呈不规则块状析出;服役后晶界上析出MC相会使其附近区域值升高,当≥0.900后σ相易于形核并长大,同时抑制MC生长;σ相析出主要受温度控制影响并满足JMA动力学关系,随服役时间延长,σ相析出量逐渐增加,析出速率逐渐降低;σ相在服役初期较强的强化效果随服役时间延长逐渐减弱。OM,SEM and TEM are used to study the precipitation ofσphase in 18Cr-9Ni-3Cu steel after serving in a power plant for 5×104 h.Furthermore,the influencing factors forσphase are discussed.The influence ofσphase evolution on the creep rupture strength is estimated from the change of Orowan stress during serving.The results indicate that MC,σphase and Cu-rich particle are the main precipitates after serving.Amounts of continuous chain-like MC precipitates along grain boundary,irregular massσphase also precipitates on the grain boundary.The rises with the precipitating of MC,σphase precipitates when≥0.900,meanwhile the growth of MC is inhibited.The growth ofσphase obeys to the JMA model.The volume fraction ofσphase increases with time,while the growth rate decreases.There are some factors governing the rate of precipitation ofσphase,and the temperature is the most important one in this work.The contribution ofσphase to creep strength decreases with serving time.

关 键 词：耐热不锈钢 长期服役 Σ相 d电子合金理论 JMA动力学关系 

分 类 号：TG113.12[金属学及工艺—物理冶金]