闪光对焊连接HRB400级钢筋疲劳试验与试验影响因素研究

Study on influence factors of fatigue performance test of HRB400 steel bars connected by flash butt welding

基于闪光对焊连接的HRB400级高强钢筋,开展一系列疲劳性能试验,得到多组双对数双折线S-N曲线和疲劳应力幅;基于此对影响疲劳试验结果的试验频率、试验应力比、试验钢筋种类、焊接残余应力四个因素进行研究。研究结果表明:高、低频试验得到的疲劳应力幅有一定的差距,低频试验得到的疲劳应力幅比高频试验低约20MPa;应力比0.4时的疲劳应力幅比应力比0.2时的疲劳应力幅低,大直径的钢筋试件的疲劳应力幅较低,32mm直径的钢筋试件在应力比0.4时的疲劳应力幅与应力比0.2时的疲劳应力幅相差不大;闪光对焊连接HRB400高强钢筋试件的疲劳应力幅比HRBF400高强钢筋试件的疲劳应力幅高约10MPa^20MPa,且大直径钢筋试件的应力幅值差异较小。

In order to study the influences of the test frequency, stress ratio, type of steel bars, welding residual stress on fatigue test results, a series of fatigue test are carried out based on the HRB400 high-strength steel bars connected by flash butt welding. Results obtained show that there is a certain gap between the fatigue stress amplitudes of the high and low frequency test, the low frequency test results are smaller than the high frequency test results about 20 MPa. Influence of high and low frequency test can be modified in the practical engineering application. The fatigue stress amplitudes of the stress ratio of 0.4 are lower than those of the stress ratio of 0.2, while the fatigue stress amplitudes of the large diameter steel bars specimens are low, and the fatigue stress amplitude of 32 mm diameter of the steel bars is basically equivalent. The fatigue stress amplitude of HRB400 high strength steel bars connected by flash butt welding are larger than that of HRBF400 about 10MPa^20MPa, and the differences of the fatigue stress amplitude of large diameter steel bars are small. In order to reduce the residual stress of the steel bars, a long static time is recommended in the engineering application, and special attention should be paid to the large diameter steel bars connected by flash butt welding.