摘  要：X80管線鋼被廣泛用于石油、天然氣輸運管道中，其鋼材構件出現塑性損傷等缺陷后易產生較大安全隱患。為保證系統運行安全，準確檢測和評估構件塑性損傷程度，該文采用金屬磁記憶方法對X80鋼材塑性損傷與損傷誘發磁場強度之間的關聯性進行實驗研究與分析。針對兩種含典型缺陷的管線鋼平板試件，采用實驗拉伸機導入不同程度應力集中與塑性損傷，同時通過光學應變測量系統實時獲取試件表面應變分布，采用自行搭建的微量磁場檢測系統測量試件表面誘發磁場法向分量。結果表明：試件誘發磁場強度法向分量與塑性損傷程度之間具有良好相關性，初步建立X80鋼塑性損傷與誘發磁場的非線性關系曲線與定量表達式，可為X80鋼材構件塑性損傷程度與無損評價提供一定參考。
關鍵詞：X80管線鋼；金屬磁記憶；塑性損傷；無損評價
文獻標志碼：A       文章編號：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