Effect of torsional prestrain on low cycle fatigue behavior of 35CrMo steel

摘要

设计了疲劳和扭转两用的试样,通过预扭转不同的角度系统研究35CrMo钢在扭转预应变下的低周疲劳性能,分析了扭转预应变后35CrMo钢的循环硬化软化特性、滞后回线、塑性应变能及循环弹性模量的变化规律,并对疲劳断口进行扫描电镜分析.结果表明:4种预扭转处理后试件均表现为明显的循环软化行为且循环软化规律及衰减的程度基本相同;循环应力范围及疲劳寿命随着预扭转角的增大而降低;应力应变滞后回线中加卸载曲线间的宽度随着预扭转角的增大而减小;塑性应变能都随着循环次数的增大而增加,且随着预扭转角的增大其增大速率下降;循环弹性模量都随着循环次数的增加而逐渐降低,且随着预扭转角的增大其衰减趋势减缓.%The dual-used samples of the fatigue and torsion was designed,and the low cycle fatigue behavior of 35CrMo steel after torsional prestrain through the different of pretorsional angles were studied.The regularity of cycle hardening-softening properties,hysteresis loop,plastic strain energy,cycle elastic modulus and the fatigue fracture of 35CrMo steel after torsional prestrain were analyzed.The results show that the four kind specimens of the pretorsional angle showed cycle softening phenomenon and the basic same level of cycle softening regularity and attenuation; the cyclic stress range and fatigue life were reduced with the pretorsional angle increased; the breadth of the curve was reduced with the pretorsional angle increased in the hysteresis loop; the plastic strain energy was increased with the fatigue cycle number increased,and the increased rate was descended with the pretorsional angle increased; the cycle elastic modulus were gradually reduced with the fatigue life cycles increased,and the attenuation of trend get lower with the pretorsional angle increased.