X70钢在交直流混合干扰下的腐蚀特性研究

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Corrosion Characteristics of X70 Steel Under AC-DC Mixed Interference

HE San1*，YURui1， ZHANGJianxiong²，LI Bin³，XUHuilan4

1.PetroleumEngineeringSchool，SouthwestPetroleum UniversityChengdu，Sichuan 61O5oo，China

2.SouthernSichuanGasDistrict，SouthwestOil&GasfieldCompany，PetroChina，Luzhou，Sichuan646oo，China 3.Shengli Oilfield Company，SINOPEC，Dongying，Shandong 2570oo，China

4.Sichuan West Natural Gas Explorationand Development Co.Ltd.，SNOPEC，Chengdu，Sichuan，China

Abstract：Incertainreas，tecossorpralelistalltionofoladgaspipeines，ig-voltagetransmissonlinsdelec trifiedrailwayscreates theriskofAC-DCmixed interferencecorrosioninburied pipelines.Through electrochemical tests， combined withpolarized lightmicroscopy，three-dimensionalopticalmicroscopyandXRD，theAC-DCmixed interference corosioncharacteristicsofX7stlintheintersectionareaofelectrifiedrlays，ig-voltagetransmissionlinesdnatural gas pipelines were studied.The results showthat：1）the criticalcurrent densityunderAC-DC mixed interference is 120A/m2 2）there is no positivecorrelationbetweentheradiusofcapacitive reactancearcandcurrentdensityunderAC-DCmixed interference;3）theAC-DCmixed interferenceanodeareanotonlycontinuedthecorosion intensityofDCinterference，butalso playedtheroleofACoscilltionandpiting，resulting insecondarylocaldamageinthecorrosionpit，formingalargenumber of pitingandcrevices，andgraduallyshowing thephenomenonofetchingwhichmakesthepartiallycorrdedX70stl （partially covered with acorosion product film）unsupported and exfoliated in solution; 4）at the current density of 180A/m2 ，the corrosion depth of the specimen under AC-DC mixed interference reaches 250μm ：

Keywords：straycurrent corrosion;AC-DC mixed interference;X7O steel; etching;synergistic effect 网络出版地址：http：//link.cnki.net/urlid/51.1718.TE.20250410.1525.002

引言

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