水压试验对管线内腐蚀的影响  

THE INFLUENCE OF HYDRAULIC TESTING ON CORROSION IN PIPELINE

作　　者：周吉锋 朱环环 袁海娜 Zhou Jifeng;Zhu Huanhuan;Yuan Haina(Shandong Boxing Shihua Natural Gas Co.,Ltd.,Binzhou,Shandong,256500;Shandong Binnong Technology Co.,Ltd.,Binzhou,Shandong,256600;Yanchang Petroleum Co.,Ltd.,Yan'an,Shaanxi,717600)

机构地区：[1]山东博兴实华天然气有限公司,山东滨州256500 [2]山东滨农科技有限公司,山东滨州256600 [3]延长石油股份有限公司,陕西延安717600

出　　处：《石油化工设备技术》2023年第1期35-38,44,I0002,I0003,共7页Petrochemical Equipment Technology

基　　金：国家自然科学基金项目(No.51006123),音速喷嘴中气液两相流临界分配特性及相分离控制理论资助资助。

摘　　要：为获得水压试验对管线内腐蚀的影响规律、做好腐蚀防护措施、提高水压试验安全性,对水压试验稳压失效的管材采用扫描电镜和XRD分析手段,分析研究了水压试验泄漏点附近管材表面显微组织、腐蚀产物以及局部腐蚀截面特点。结果表明:管材表面存在较严重局部腐蚀和管线轴向裂纹是造成水压试验稳压失效的双重原因;水压试验管道内壁腐蚀产物主要是较稳定的γ-Fe_(2)O_(3)、α-Fe(OH)_(2),同时还存在少量不稳定的腐蚀中间产物γ-Fe(OH)_(2),因其保护性差,导致管道底部仍处于活性腐蚀阶段;水压试验管道内壁腐蚀产物膜存在内层、中间、外层结构,外层组织松散、不稳定、保护性差,中间层多为较稳定的α-Fe(OH)_(2),内层氧含量较高,与金属基体之间结合较紧密,多为非常稳定的γ-Fe_(2)O_(3)外层、中间和内层之间存在缝隙,易产生缝隙腐蚀导致严重的局部腐蚀。In order to obtain the influence laws of hydraulic testing on the corrosion in the pipeline,take good measures for corrosion protection and improve the safety of hydraulic testing,scanning electron microscope and XRD analysis methods are adopted to analyze the tube that has failed in the hydraulic testing.The microstructure,corrosion products and local corrosion cross sections of the pipe surface near the leakage point of hydraulic testing are analyzed and studied.The results show that the existence of more serious local corrosion on the surface of the pipe and axial cracks in the pipeline are the two causes for the failure of pressure stabilizing during the hydraulic testing;the corrosion products of the inner wall of the hydraulic test pipe are mainly stable gamma-Fe_(2)O_(3),α-Fe(OH)_(2),and there is also a small amount of unstable corrosion intermediate product gamma-Fe(OH)_(2) with poor protection,causing the bottom of the pipeline to be still in active corrosion phase;the inner wall of the hydraulic testing pipeline corrodes the material film in the inner,middle,and outer layers;the outer layer is loose,unstable,and poorly protected;the middle layer is mostly a relatively stableα-Fe(OH)_(2),and the inner layer has a higher oxygen content;the binding between the metal matrix is relatively close,and it is mostly very stable gamma-Fe_(2)O_(3)there's a gap between the outer layer,the middle layer and the inner layer,which is prone to crevice corrosion and leads to severe local corrosion.

关 键 词：水压试验 局部腐蚀 轴向裂纹 腐蚀产物膜 三层结构 

分 类 号：TE988.2[石油与天然气工程—石油机械设备]