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目的：研究Q345角钢构件的疲劳性能随腐蚀损伤发展的变化规律，为分析“腐蚀-疲劳”交替循环工况下试件疲劳性能变化情况奠定基础。方法首先通过连续疲劳振动和间隔疲劳振动两种疲劳试验，测试分析了疲劳荷载施加方式对试件疲劳性能的影响，其中，试件间隔振动分三次完成，每次振动次数为连续疲劳振动次数的1/3。然后，根据不同“浸泡-晾置”次数，给出了三种腐蚀方式，并在pH值为2的酸性溶液中对试件进行加速腐蚀损伤试验。采取“腐蚀-疲劳”交替循环加载方式对3组39根Q345角钢构件进行腐蚀疲劳试验，由试件腐蚀疲劳破坏的试验现象及测试结果，分析试件疲劳性能随腐蚀疲劳损伤的变化规律，并研究Q345角钢试件的风致振动疲劳性能因大气环境中腐蚀损伤发生及发展的退化规律。结果疲劳荷载为221.43 MPa时，三种“腐蚀-疲劳”工况下，CF1、CF2与CF3相比，试件的疲劳寿命分别退化了5.1%和2.7%。疲劳荷载为308 MPa和221.43 MPa时，单点试验结果未随腐蚀方式变化而发生明显变化，但是当疲劳荷载减小到156.22 MPa时，CF1、CF2与CF3相比，试件的疲劳寿命分别退化了6.3%和4.5%。结论腐蚀损伤试验中“浸泡-晾置”交替循环次数越多，损伤越大，试件疲劳寿命退化，反映Q345角钢构件的疲劳性能受大气环境干湿交替腐蚀损伤影响明显。同一腐蚀方式中，疲劳荷载越小，腐蚀的影响越显著，脆性破坏特征越明显。

ABSTRACT:Objective To study the effect of corrosion on the fatigue properties of Q345 equilateral angle steel, which lays foundation for the analysis of fatigue performance variation of specimens under condition of alternating cycles of "corro-sion-fatigue".Methods Firstly, based on the test results of continuous fatigue vibration and interval fatigue vibration, the effect of fatigue loading modes on the fatigue performance of the specimens was analyzed. The interval vibration of the specimens was completed in three steps, and the vibration times of each step was 1/3 of that of continuous fatigue vibration. Then, three kinds of etching methods were adopted according to the different times of "immersion-drying", and accelerated corrosion damage test was conducted in acid solution with a pH value of 2. With different corrosion, 3 groups 39 Q345 equilateral angle steel was stu-died on by the fatigue cyclic loading test. Corrosion fatigue test was carried out on 3 groups of 39 Q345 angle steel parts using "corrosion-fatigue" alternate cycling loading. Based on the phenomena and results of the corrosion fatigue tests, the changing law of fatigue performance with corrosion fatigue damage was analyzed, and the degeneration law of wind-induced vibration fa-tigue properties of Q345 angle steel with the occurrence and development of corrosion damage in atmospheric environment was investigated. ResultsWhenSmax was 221.43 MPa, the average fatigue life in corrosion modes CF2 and CF2 of the 8 specimens was decreased by 5.1% and 2.7% as compared with CF3, whereas the fatigue life was not changed significantly whenSmax was 308.39 MPa or 221.43 MPa, but whenSmax decreased to 156.22 MPa, the fatigue life of CF1 and CF2 was decreased by 6.3% and 4.5% as compared with that of CF3, respectively.ConclusionWith increasing times of “Immersion-drying” alternating cycles, the damage increased, and the fatigue life of specimens decreased, showing that the corrosion fatigue life of specimens was obviously affected by the atmospheric environmental dry-wet alternate corrosion. In the same type of corrosion, the smaller the fatigue load, the more significant the influence of corrosion, and the more obvious the brittle failure characteristics.