应力比对过共析钢轨疲劳裂纹扩展行为的影响  

Effects of Stress Ratio on Fatigue Crack Growth Behavior of Hypereutectoid Rail

作　　者：戴宇恒 陈林[1] 崔健伟 DAI Yuheng;CHEN Lin;CUI Jianwei(School of Material and Metallurgy,Inner Mongolia University of Science&Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《热加工工艺》2022年第22期15-18,共4页Hot Working Technology

基　　金：国家自然科学基金项目(51361021);内蒙古自治区科技重大专项项目(ZDZX2018024)。

摘　　要：通过对不同应力比下过共析钢轨进行疲劳裂纹扩展实验,研究了应力比对过共析钢轨裂纹扩展速率的影响,对比8℃/s冷速与轧态过共析钢在应力比增大时疲劳循环次数的变化,分析热处理对过共析钢轨应力比敏感度的影响。结果表明:应力比是影响过共析钢轨疲劳性能的主要外部因素,热处理能在一定程度上降低应力比的变化对其疲劳裂纹扩展的影响及敏感度。随应力比的增加,疲劳循环次数增加,轧态过共析钢轨疲劳循环次数增加5.31万次,8℃/s冷速淬火工艺过共析钢轨疲劳循环次数增加14.64万次;在相同ΔK下,随应力比的增加,疲劳裂纹扩展速率增加。应力比R由0.1增加到0.3时,8℃/s冷速淬火工艺过共析钢轨相较轧态过共析钢轨的循环次数提升了9.33万次。Based on the fatigue crack growth experiments of hypereutectoid rail under different stress ratios, the effects of stress ratio on the crack growth rate of hypereutectoid rail were studied. The fatigue cycles of 8 ℃/s and rolled hypereutectoid steel were compared when the stress ratio increases. The influence of thermal treatment on the sensitivity of hypereutectoid rail to stress ratio was analyzed. The results show that the stress ratio is the main external factor affecting the fatigue performance of hypereutectoid rail, and the heat treatment can reduce the influence and sensitivity of the change of stress ratio on fatigue crack growth to a certain extent. The fatigue cycle number of rolled hypereutectoid rail increases by 53,100 cycles,and the fatigue cycle number of hypereutectoid rail by 8 ℃/s cold quenching process increases by 146,400 cycles;at the sameΔK, with the increase of stress ratio, the fatigue crack growth rate increases. When the stress ratio R increases from 0.1 to 0.3,the cycle times of the hypereutectoid steel rail in 8 ℃/s cold quenching process increase by 93,300 cycles compared with that of the rolled hypereutectoid rail.

关 键 词：应力比 过共析钢轨 热处理 裂纹扩展 

分 类 号：TG142.1[一般工业技术—材料科学与工程]