9%～12%Cr马氏体钢蠕变疲劳寿命的影响因素研究

Study on the Influence Factors of Creep-fatigue Life of 9%～12%Cr Steel

根据P92钢在600℃下、X12CrMoWVNbN10-1-1钢在620℃下以及P91钢在575℃下应力控制加载蠕变-疲劳交互作用试验数据,研究了9%~12%Cr马氏体钢蠕变-疲劳寿命的影响因素。研究发现,当保载时间较短时,保载时间越长,疲劳寿命越短,但当保载时间较长时,保载时间对疲劳寿命的影响可以忽略不计;保载时间较短时,疲劳寿命均与应力比成反比,但应力比对于疲劳寿命所产生的影响不大,且随着保载时间的增加而逐渐减弱。通过对比X12CrMoWVNbN10-1-1钢在620℃时的疲劳寿命与P92钢在600℃时的疲劳寿命发现,P92钢的疲劳寿命更长;当温度和应力比相同,最大应力为250 MPa的P91钢的疲劳寿命比最大应力为260 MPa的P91钢的疲劳寿命相对更短,因此温度和最大应力是影响9%~12%Cr马氏体钢蠕变-疲劳寿命的最主要因素。

According to the experimental data of the interaction of load controlled creep-fatigue on P92 at 600 ℃ and X12CrMoWVNbN10-1-1 at 620 ℃ and P91 at 575℃, the effect on the creep-fatigue life of 9% ～ 12% martensitic steels is investigated. The results show that when the hold time is relatively short, the fatigue life decreases with the increase of the loading time. Howev-er, when the hold time is as long as a certain value, the load time and the stress ratio have almost no effect on the fatigue life. The fatigue life of X12CrMoWVNbN10-1-1 steel at 620 ℃ is much less than that of P92 steel at 600 ℃. When at the same temperature and with the same stress ratio, the P91 steel with the maximum stress of 250 MPa is relatively less than the life of the P91 steel with the maximum stress of 260 MPa. Therefore, the temperature and the maximum stress are the most important factors that affect the creep-fatigue life of 9% ～ 12% Cr martensitic steel.