两种高强度轴承钢的动态硬化现象及其循环应力—应变滞后回线的特性

The Dynamic Hardening and the Characters of Cyclic Stress-Strain Hysteresis Loop in Two High Strength Bearing Steels

对两种美国高强度轴承钢进行了高频脉动扭转疲劳试验,所得结果与常规的单向扭转试验差异较大。轴承钢在循环应力作用下出现硬化现象.屈服点明显提高。通过系列试验建立了相应的循环应力(?)应变滞后回线,提出并测定了一些能代表该材料动态性能的新指标:塑性模数 M、动态屈服强度(?)等。同时对循环周次、塑性应变量、寿命、试样表面光洁度及其形状等因素的影响进行了考查,找出了规律。这些指标及其影响因素的提出对更科学地评定轴承材料性能提供了有用的数据。

In this paper,the high frequency cyclic torsion fatigue tests have been done for two American high strength bearing steels.All the results are compared with those from monotonic torsion tests.It is found that they are quite different.Under cyclic stress, the dynamic hardening can be Observed in bearing steels and the yield strength is raised evidently.Some eyelie stress-strain hysteresis loops are established after a series of tests and some parameters:plastic modulus,dynamic yield strensth,and so on are prposed to difine the dynamic characters of bearing steels.The authors explore the effects of the cycles,plastic strain range,life,roughness and the shape of specimen and find out some rules.All of these are beneficial for the scientific valuation of bearing steels.