摘要
文中在600℃试验条件下对P92钢焊条熔敷金属进行持久测试和组织演变研究。利用等温线法和Larson-Miller法外推10万h的持久强度分别为136 MPa和128 MPa。持久断裂试样抛光腐蚀后发现,其显微组织均保持回火马氏体形态。利用SEM对持久断裂试样的组织演变进行定性分析,持久试样主要的析出相为分布于板条马氏体晶界和大角度亚晶界的M23C6和Laves相;随高温持久时长的延长,Laves相发生聚集粗化,M23C6相发生Ostwald熟化。蠕变孔洞依附Laves相形核;随持久时间的延长,其数量密度呈下降趋势,当量直径有增大趋势;蠕变孔洞也最终导致了试样的断裂。
Creep-rupture tests and microstructure evolution of P92 steel electrode deposited metal at 600 ℃ were carried out in this paper. By using isothermal curve method and Larson-Miller method to extrapolate creep-rupture strength of P92 steel electrode deposited metal after 105 h service, the creep-rupture strength was 136 MPa and 128 MPa respectively. The microstructure of creep-ruptured test specimen was found to be tempered martensite after polished and etched. The microstructure evolution of creep-ruptured test specimen was analyzed by SEM. The main precipitates of specimens were M23 C6 and Laves phases which distributed on grain and sub-grain boundaries in lath martensite. The Laves phase accumulated with the time extension of creep-rupture test and the M23 C6 phases accrued Ostwald ripening.Creep cavities nucleated on Laves phase. With the extension of time, cavities number density decreased and the equivalent diameter increased. Creep cavities leaded to fracture of the specimens.
作者
林永祥
LIN Yong-xiang(POWERCHINA Shanghai Power Equipment and Manufacturing Co.,Ltd.,Shanghai 201316,China)
出处
《焊接技术》
2021年第2期13-17,I0013,I0014,共7页
Welding Technology
关键词
P92钢
熔敷金属
持久测试
组织演变
P92 steel
deposited metal
creep-rupture test
microstructure evolution
