摘  要：X80管线钢被广泛用于石油、天然气输运管道中，其钢材构件出现塑性损伤等缺陷后易产生较大安全隐患。为保证系统运行安全，准确检测和评估构件塑性损伤程度，该文采用金属磁记忆方法对X80钢材塑性损伤与损伤诱发磁场强度之间的关联性进行实验研究与分析。针对两种含典型缺陷的管线钢平板试件，采用实验拉伸机导入不同程度应力集中与塑性损伤，同时通过光学应变测量系统实时获取试件表面应变分布，采用自行搭建的微量磁场检测系统测量试件表面诱发磁场法向分量。结果表明：试件诱发磁场强度法向分量与塑性损伤程度之间具有良好相关性，初步建立X80钢塑性损伤与诱发磁场的非线性关系曲线与定量表达式，可为X80钢材构件塑性损伤程度与无损评价提供一定参考。
关键词：X80管线钢；金属磁记忆；塑性损伤；无损评价
文献标志码：A       文章编号：1674-5124（2016）01-0021-05
Nondestructive evaluation of magnetic field induced by plastic deformation
of X80 steel
LI Yunfei， WEI Liming， WAN Qiang
（Institute of Systems Engineering，CAEP，Mianyang 621900，China）
Abstract: X80 steel is widely used in oil and gas transport pipelines. Hidden dangers would be triggered if plastic damage and other defects appear in mechanical components. In order to detect accurately and assess the damage degree and ensure safety in system operation， the relation between plastic deformation in X80 steel and damage-induced magnetic field has been experimentally studied via metal magnetic memory （MMM）. Different levels of plastic strains have been imported into two kinds of X80 steel specimens for several times. The strain distribution has been measured through an optical measurement system and the normal components of magnetic memory signals have been obtained by a self-built micro-magnetic detection system. The experimental results have revealed that the normal components of deformation-induced magnetic field intensity are highly correlated with plastic deformation degrees. Furthermore， we have initially established a nonlinear curve and a quantitative expression for plastic deformation and damage-induced magnetic field， thus providing a basis for quantitative evaluation of plastic deformation in X80 steel components.
Keywords: X80 steel； metal magnetic memory； plastic deformation； nondestructive evaluation