摘要
锻件截面尺寸变化及表面加工缺陷所引起的应力集中往往会导致其早期疲劳失效,因而要求钢材具有高的缺口疲劳性能和低的疲劳缺口敏感度。为了明确非调质钢的缺口疲劳破坏行为,采用旋转弯曲疲劳试验机研究了一种锻造用中碳非调质钢38MnVS在不同应力集中系数Kt(1、2、4)下的高周疲劳破坏行为。结果表明,试验料的光滑和缺口疲劳S-N曲线均存在明显的疲劳极限,Kt对试验料的疲劳极限和疲劳缺口敏感度qf具有显著的影响,当Kt从1(光滑试样)提高到2和4时,疲劳极限分别降低了48%和67%,qf值分别为0.93、0.68,呈现出较高的疲劳缺口敏感性。试验结果及文献数据的拟合分析表明,可采用Kt的幂函数来表征试验料的缺口疲劳极限,并提出了预测铁素体+珠光体型非调质钢在不同Kt下疲劳极限的一种简便高效方法。
Many actual forging components contain inevitable geometrical discontinuities or machining notches which may cause local stress concentration and thus induce early fatigue failure when it is subjected to cyclic loading.Therefore,high notch fatigue properties are also required to forging steels.In order to explore the notch fatigue behavior of microalloyed medium carbon forging steels,the high-cycle fatigue behaviour of a commercially used medium-carbon forging steel 38 MnVS under different stress concentration factors(Kt=1,2,4)was studies by using rotating bending fatigue testing.The results show that there are notable fatigue limits in the S-N curves for both the smooth and notch specimens of the as-forged tested steel.There are significant influences of Kton the notch fatigue limit and fatigue notch sensitivity(qf).When Ktwas increased from 1 to 2 and 4,the fatigue limit decreased by 48%and 67%,respectively,and the qfvalue was 0.93 and 0.68,respectively,which reveals that the as-forged tested steel has high fatigue notch sensitivity.It is found that fatigue limit is a power function of Ktwith its coefficient equals to smooth fatigue limit based on the results of this study and those in the literature.Finally,a simple and efficient method of estimating the notch fatigue limit of ferritic-pearlitic medium-carbon forging steel under different Ktis proposed.
作者
刘湘江
陈桢
惠卫军
LIU Xiang-jiang;CHEN Zhen;HUI Wei-jun(Central Research Institute,Baoshan Iron and Steel Co.,Ltd.,Shanghai 201999,China;School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《钢铁》
CAS
CSCD
北大核心
2020年第7期106-112,共7页
Iron and Steel
基金
国家重点研发计划资助项目(2016YFB0300100)。
