文献类型：期刊文献

中文题名：25Cr2Ni2MoV钢焊接接头的超高周疲劳特性

英文题名：Very High Cycle Fatigue Behavior of 25Cr2Ni2MoV Steel Welded Joint

作者：刘龙隆[1];轩福贞[1];朱明亮[1]

机构：[1]华东理工大学机械与动力工程学院,上海200237

年份：2014

卷号：50

期号：4

起止页码：25

中文期刊名：机械工程学报

外文期刊名：Journal of Mechanical Engineering

收录：CSTPCD;;EI(收录号：20141317523428);Scopus;北大核心:【北大核心2011】；CSCD:【CSCD2013_2014】；

基金：国家高技术研究发展计划(863计划;2012AA040106);国家科技支撑计划(2011BAK06B03)资助项目

语种：中文

中文关键词：焊接接头;超高周疲劳;裂纹萌生;气孔;夹杂物

外文关键词：welded joint; very high cycle fatigue; crack initiation; pore; inclusion

摘要：对25Cr2Ni2MoV钢焊接接头开展常温拉压条件下的超高周疲劳试验,并对失效试样进行断口分析,研究焊接接头的疲劳失效机理。结果表明,疲劳寿命曲线呈现阶梯状:在高应力短寿命区,疲劳断裂发生在试样母材区较多,多为表面或次表面夹杂物裂纹萌生;在低应力长寿命区,疲劳断裂发生在试样焊缝区较多,多为内部气孔裂纹萌生。断口分析发现:缺陷(裂纹源)尺寸较小或者越靠近试样内部,疲劳寿命越长,且较小缺陷同内部较大缺陷具有相似的裂纹萌生潜力。通过有限元模拟疲劳试样内部微缺陷处的应力分布得出,焊缝区气孔和夹杂物周围的应力集中程度大于母材区夹杂物。结合断口分析发现,母材区弥散分布的粒状颗粒夹杂物数量较多,并且聚集起来会形成更大的缺陷,相比焊缝区夹杂物更容易萌生疲劳裂纹。
Conventional fatigue test is conducted in 25Cr2Ni2MoV steel welded joint specimen at room temperature. The fatigue failure mechanism in welded joint is investigated by fatigue test and microscopic analyses. Results show that the stress-fatigue life relationship presented a stepwise shape. In high cycle fatigue（HCF） regime, base metal is preferential fracture sites, which are originated at surface or subsurface inclusions. Whereas in the very high cycle fatigue（VHCF） regime, fatigue cracks are always initiated at pores in the weld metal. The fatigue life will be longer in the condition of small surface defect size or interior defect as fatigue crack initiation. Small surface defect with large interior defect has similar potential for crack initiation. Stress distribution of fatigue specimen at micro-defects are performed by finite element analyses, and it shows that the stress concentration around pore and inclusion in the weld metal are larger than inclusion in base metal. It is found that large quantities of granular particles disperse inclusions in base metal will form bigger defects and these defects are easier to initial fatigue crack than inclusions in the weld metal.