S135钻杆钢的单轴疲劳性能对比

摘要

The fatigue life of S135 drill pipe steel was tested by tension-compression loading and torsion loading under uniaxial loading during the fatigue test.The quantitative formulas of uniaxial fatigue life were obtained by regression analysis method,and the fatigue fracture mechanism was analyzed.The results show that a linear correlation was found between fatigue life and effective stress in the double logarithmic plots.The ratio of torsion fatigue limit to tension-compression fatigue limit was 0.682.Cracks initiated from the samples surface under tension-compression loading as well as torsion loading.For the tension-compression fatigue and the torsion fatigue samples,the main characteristics for cracks propagation were fatigue striations and sheared ripple marks,respectively.%通过疲劳试验测定了S135钻杆钢在单轴对称拉-压和扭-转加载条件下的疲劳寿命,应用回归分析方法得到了单轴疲劳寿命的定量公式,并对疲劳断裂的机制进行了分析。结果表明：在双对数坐标中,疲劳寿命与有效应力幅呈良好的直线关系;扭-转疲劳极限与拉压疲劳极限之比为0.682;拉-压加载和扭-转加载下的裂纹均萌生于试样表面;拉-压疲劳试样的裂纹扩展以疲劳条带为主要特征;扭-转疲劳试样的裂纹扩展以剪切型涟波花样为主要特征。