摘要
为了研究高钢级油气管线环焊缝脆性开裂失效与微小残余塑性应变之间的关系问题,采用背散射电子衍射对不同应变下的X70管线钢进行了表征研究。通过四点弯曲试验和拉伸试验制备带有残余塑性应变的样品,表征了衍射带对比度、核平均取向差与应变的关系。结果表明:X70钢,对于10%以内的塑性变形,金相和硬度等工程手段无法识别;在X70钢管四点弯曲的梯度塑性应变预制样品和系列拉伸样品中,材料EBSD衍射带对比度与微小塑性变形相关性较差,而核平均取向差与±2%以上的塑性变形有较好正相关性,有望用于实际管线残余塑性变形的定性或半定量评估。
In order to study the relationship between brittle cracking failure and small residual plastic strain of high grade oil and gas pipeline girth weld,X70 pipeline steel under different strains was characterized by electron backscatter diffraction.Samples with residual plastic strain were prepared by four-point bending test and tensile test,and the relationship between band contrast,kernel average misorientation and strain was characterized.The results show that the metallographic structure and hardness of X70 steel can not be recognized for the plastic deformation within 10%.In the four-point bending gradient plastic strain pre-fabricated specimens and a series of tensile samples of X70 steel,the correlation between electron backscatter diffraction diffraction band contrast and microplastic deformation is relatively poor,while the kernel average misorientation has a good positive correlation with plastic deformation of above±2%,which is expected to be used for qualitative or semi-quantitative evaluation of residual plastic deformation of actual pipelines.
作者
孟彤
孙超
王汉奎
商学欣
于宇新
孟涛
帅健
宋明
MENG Tong;SUN Chao;WANG Hankui;SHANG Xuexin;YU Yuxin;MENG Tao;SHUAI Jian;SONG Ming(China Special Equipment Inspection&Research Institute,Beijing 100029,China;China University of Petroleum(Beijing),Beijing 102249,China)
出处
《流体机械》
CSCD
北大核心
2023年第2期20-27,共8页
Fluid Machinery
基金
国家重点研发计划项目(2022YFC3006304)
国家网集团联合管道有限责任公司西气东输分公司(GWHT20210040408)
“焊接与失效控制”和“材料微损评价”二级科研团队研究项目(2021XKTD023,2021XKTD021)。
关键词
X70钢
塑性变形
电子背散射衍射
核平均取向分布差
X70
plastic deformation
electron backscatter diffraction
kernel average misorientation
