10CrNiMo高强钢的低周疲劳特性

Low cycle fatigue characteristic of 10CrNiMo high-strength steel

采用圆形横截面光滑试样,通过轴向不同应变幅控制的低周疲劳试验,研究了10CrNiMo高强钢的低周疲劳特性,包括循环应力-应变行为、应变-寿命特点、循环应力响应及其力学滞后现象,给出了相应的疲劳参数、循环软硬化特性及应变滞后规律.对裂纹扩展方向及试样疲劳断口的观察表明:裂纹扩展面与轴向力呈现多角度关系,裂纹萌生于试样表面,沿断口周边分布,且具有多源性;疲劳裂纹主要以锐化--钝化机制扩展.

Low cycle fatigue characteristics of 10CrNiMo high-strength steel were investigated with smooth rotundity-section specimens through low cycle fatigue testing under axial loading controlled by different strain amplitudes, including cyclic stress-strain behavior, strain-life feature, cyclic stress response and mechanical hysteresis. The relevant fatigue parameters, cyclic softening/hardening property and strain hysteretic rule were given on the basis of experimental data. Observations of crack propagation orientation and frac- ture surfaces show that fatigue cracks initiate with multi-initiation sites from the specimen surface, distribute along the fracture border, and propagate along planes with different angles to axial force. Fatigue crack propagation is mainly in the blunting-resharpening mechanism.