P91钢在高温蠕变过程中的组织及硬度演化  

Microstructure and Hardness Evolution of P91 Steel during High Temperature Creep

作　　者：张开 王学[1] 倪满生 刘俊建 杜成超 ZHANG Kai;WANG Xue;NI Mansheng;LIU Junjian;DU Chengchao(School of Power and Machinery,Wuhan University,Wuhan 430072,China;Datang Boiler Pressure Vessel Inspection Center Co.,Ltd.,Hefei 230088,China;School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]武汉大学动力与机械学院,湖北武汉430072 [2]大唐锅炉压力容器检验中心有限公司,安徽合肥230088 [3]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《热加工工艺》2023年第8期21-25,共5页Hot Working Technology

基　　金：国家自然科学基金项目(52174370)。

摘　　要：进行了P91钢在650℃/70 MPa下的加速蠕变试验,利用布氏硬度计、SEM、TEM和EDS表征了其在蠕变过程中的组织及硬度变化,分析了组织演化对硬度降低的影响。结果表明:P91钢硬度在蠕变前期(小于40%蠕变寿命)下降较为缓慢,在蠕变中后期的下降幅度明显增大,蠕变2935 h后的硬度由222 HB下降至175 HB。蠕变过程中的组织退化机制为位错密度显著降低,晶粒尺寸明显增加,M23C6聚集长大,逐渐丧失马氏体板条形貌。位错强化的降低是P91钢硬度下降的主要原因。The accelerated creep tests of P91 steel at 650℃/70 MPa were carried out.The microstructure and hardness changes during creep were characterized by Brinell hardness tester,SEM,TEM and EDS.The effects mechanism of microstructure evolution on the hardness reduction were analyzed.The results show that the hardness of P91 steel decreases slowly in the early stage of creep(less than 40%creep life),and the decreasing range increases significantly in the middle and late stage of creep.The hardness decreases from 222 HB to 175 HB after creep for 2935 h.The mechanism of microstructure degradation during creep is that the dislocation density decreases significantly,the grain size increases obviously,M23C6 aggregates and grows,and the lath morphology of martensite gradually loses.The decrease of dislocation strengthening is the main reason for the hardness decrease of P91 steel.

关 键 词：P91钢 高温蠕变 组织 硬度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]