国产A508-3钢在模拟AP1000一回路水环境下的疲劳性能研究

Fatigue Behavior of Domestic A508-3 Steel under Simulated AP1000 Primary Coolant Environment

反应堆压力容器(RPV)钢在一回路水环境下的疲劳性能是评价其设计寿命的重要参数。本文针对国产A508-3钢开展了模拟AP1000一回路水环境的低周疲劳性能试验研究,获得了321℃、15.5 MPa及0.1 ppm溶解氧水环境下的疲劳行为数据和断裂机理。研究结果表明,国产A508-3钢峰值应力随应变幅的增大而逐渐增大,疲劳试验过程中试样表现出循环硬化、循环软化和饱和3个阶段;在应变幅由0.2%逐渐增加至0.6%的过程中,疲劳周次从10~5逐渐降低至10~2;疲劳断口具有疲劳和腐蚀特征,属于典型的腐蚀疲劳断裂。

Fatigue property of RPV steel is one of the most key parameters in the RPV design life evaluation.The fatigue tests of domestic A508-3 steel under the simulated AP1000 primary coolant environment were carried out,the fatigue data of 0.04%/s strain rate,321℃,15.5 MPa and 0.1 ppm dissolved oxygen were obtained.The results show that the peak stress increases as the strain amplitude.During the fatigue test,the specimens show three stages:Cyclic hardening,cyclic softening and saturation.Fatigue life decreases from 10~5 to 10~2,as the strain amplitude increases from 0.2%to 0.6%.The fatigue fracture surface morphology has the characteristics of fatigue and corrosion,which indicates the typical corrosion fatigue fracture.