Experimental Study Of Pipeline Inner Corrosion Basing On Electrical Resistance Technique

As inner-corrosion is one of the main factors of pipeline failure, inner-corrosion monitoring increasingly become a hot issue in pipeline industry. Traditional corrosion monitoring techniques are not suitable for any condition meanwhile they has limited things to do about inner-corrosion of pipeline. The focus of the work was to understand the circumferential characteristics of.pipeline inner corrosion by a experimental platform with special ring-pair corrosion probes.Firstly the corrosion of X65 pipeline steel under seawater environment (3.5% NaCl) was studied using different monitoring methods. Utilized ER and electrochemical methods to monitor corrosion of the same special specimens, then compared the results with the weightlessness method. The corrosion rates using ER and weightlessness method had a high concordance, while the result of electrochemical method was much higher at later period. ER method is more suitable for long time corrosion monitor. The corrosion rate of X65 steel by ER method is 0.06-0.36 mma.Established an experimental platform based on ring-pair corrosion probe that overcome defects of traditional probe to study the pipeline inner-corrosion characteristics. Obtain the basic parameters of ring-pair probe for corrosion measurement.by calibration test. Finally long term experiment of was carried out based on the platform. The result shows that the inner-corrosion of pipeline exists circumferential difference, the bottom of pipeline is corroded faster due to deposit; the platform realizes the circumferential corrosion monitoring and has high sensitive for local corrosion; the effect of inhibitor for pipeline have circumferential difference.