中国铁道科学2018，Vol.39Issue(1)：100-107,8.DOI:10.3969/j.issn.1001-4632.2018.01.14
转向架用SMA490BW钢焊接接头超高周疲劳性能的影响因素
Influence Factors for Very High Cycle Fatigue Performance of SMA490BW Steel Welded Joint for Bogie
摘要
Abstract
SMA490BW steel welded specimen for bogie was treated by means of ultrasonic impact,low temperature heat treatment and mechanical grinding method (smoothing weld reinforcement and grinding weld toe) under the impact current of 1.5 A,and the impact time of 5,10,15,and 20 min,respectively.The influence degree of such factors as stress concentration,grain refinement and residual stress on the very high cycle fatigue performance of welded joint was analyzed and compared respectively through residual stress measurement and ultrasonic fatigue test.The changes of crack initiation location and the failure mode of the welded joint before and after the ultrasonic impact were studied with the aid of the scanning electron microscope observation of fatigue fracture.Results show that the fatigue life of welded specimen has been improved to some extent by ultrasonic impact or mechanical grinding.The effect of smoothing weld reinforcement on increasing the fatigue life of welded joint is the most remarkable,which can be improved by about 86.4 times than that of the original welded specimen.The contribution ratio of improving the fatigue life of the welded specimen is about 59％,28％ and 13％ respectively by means of decreasing the stress concentration,refining the surface grain and introducing residual compressive stress.Most fatigue cracks initiate on the weld toe surface both for as-welded and ultrasonic treated specimens.Some cracks of ultrasonic treated specimen initiate on the surface of machining defects,a small number of cracks initiate at the defects inside the material and propagate to fracture failure.关键词
超声冲击/热处理/机械打磨/超高周疲劳/残余应力/晶粒细化/应力集中Key words
Ultrasonic impact/Heat treatment/Mechanical grinding/Very high cycle fatigue/Residual stress/Grain refinement/Stress concentration分类
交通工程引用本文复制引用
于影霞,丁江灏,谢学涛,张枝森,何柏林..转向架用SMA490BW钢焊接接头超高周疲劳性能的影响因素[J].中国铁道科学,2018,39(1):100-107,8.基金项目
国家自然科学基金资助项目(51365014) （51365014）
江西省工业支撑重点项目(20161BBE50072) （20161BBE50072）
