论文部分内容阅读
为了研究中碳钢在悬臂弯扭载荷下的超低周次疲劳断裂适宜参数及断裂机理,采用SEM技术分析断口形貌,应用自制悬臂弯扭夹具和新型电液伺服高频疲劳试验机测试试样的疲劳寿命。结果表明,悬臂弯扭疲劳载荷能够达到低能耗、断面高质量、超低周次高效率的断裂设计要求,适宜的切口参数为:切口尖端半径r=0.06~0.4 mm,切口深度t/b≈0.075。悬臂弯扭载荷下中碳钢断口的疲劳源呈多源性,存在二次裂纹和撕裂棱,对裂纹扩展起主要作用的是Ⅰ型成分。
In order to study the suitable parameters and fracture mechanism of medium low carbon cycle fatigue fracture under the bending and torsional load of cantilever, the fracture morphology of the medium carbon steel was analyzed by SEM and the self-made cantilever bending fixture and the new electro-hydraulic servo high-frequency fatigue testing machine Kind of fatigue life. The results show that the fatigue load of cantilever bending and torsion can meet the design requirements of low energy consumption, high quality and low cycle and high efficiency fracture. The suitable cutting parameters are: cutting tip radius r = 0.06-0.4 mm, cutting depth t / b≈ 0.075. The fatigue source of medium carbon steel fracture under cantilever torsional load is multi-source, with secondary cracks and tearing edges, and type I component which plays a major role in crack propagation.