中国测试李云飞， 韦利明， 万 强
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