文献类型：期刊文献

中文题名：NiCrMoV钢焊接接头热影响区疲劳短裂纹扩展原位试验研究

英文题名：In-situ Observation of Short Fatigue Crack Growth in Heat-affected-zone of NiCrMoV Steel Welded Joint

作者：朱明亮[1];王德强[1];轩福贞[1]

机构：[1]华东理工大学机械与动力工程学院,上海200237

年份：2013

卷号：49

期号：14

起止页码：31

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：20133316623554);Scopus;北大核心:【北大核心2011】；CSCD:【CSCD2013_2014】；

基金：国家自然科学基金(51205131);上海市自然科学基金(12ZR1442900)资助项目

语种：中文

中文关键词：焊接接头;热影响区;疲劳裂纹扩展;短裂纹原位试验

外文关键词：Welded joint Heat-affected-zone Fatigue crack growth Short crack In-situ test

摘要：对NiCrMoV转子钢焊接接头,将初始裂纹置于热影响区的完全淬火-回火区、不完全淬火-回火区和回火区,基于扫描电镜(Scanning electron microscopy,SEM)-微拉伸试验装置,开展真空条件下疲劳短裂纹扩展行为的原位试验,研究焊接接头热处理后微区的疲劳破坏机理。结果表明,热影响区内疲劳物理短裂纹的扩展是不连续的,K仍可作为裂纹扩展的驱动参量,材料强度水平控制疲劳短裂纹扩展方向。在完全淬火-回火区,短裂纹扩展受到大尺寸晶粒和板条马氏体的影响,裂纹易偏折,疲劳抗力最好;而回火区的晶粒尺寸和强度较小,疲劳门槛值较低,裂纹抗力较弱。在不完全淬火-回火区,晶界析出碳化物较多,疲劳裂纹主要以沿晶方式扩展,裂纹扩展抗力最差。
In-situ observation of short fatigue crack growth is conducted based on scanning electron microscopy and micro-tensile module. The initial cracks are located in heat-affected-zone（HAZ） of a NiCrMoV steel welded joint, i.e., fully quenched-tempered zone, partially quenched-tempered zone and tempered zone. Results show that the physically short cracks grow discontinuously though still driven by AK in the HAZ, and the fatigue crack growth direction is influenced by the strength distribution. Fatigue crack propagation resistance in the fully quenched-tempered zone is the highest due to the barrier effects of the lathy tempered martensite and larger grain size leading to more tortuous crack propagation path. Whereas in the tempered zone the grain size and strength are relatively lower, and thus inferior fatigue behavior. Nevertheless, the lowest fatigue performance locates in the partially quenched-tempered zone, where the crack growth is tended to be intergranular due to the large amount of carbide precipitates around grain boundary.