STRESS CORROSION CRACKING OF X80 PIPELINE STEEL AT COATING DEFECT IN ACIDIC SOIL

doi:10.11900/0412.1961.2015.00641

CORC > 金属研究所 > 中国科学院金属研究所

	STRESS CORROSION CRACKING OF X80 PIPELINE STEEL AT COATING DEFECT IN ACIDIC SOIL
	Yan Maocheng; Yang Shuang; Xu Jin; Sun Cheng; Wu Tangqing; Yu Changkun; Ke Wei
刊名	ACTA METALLURGICA SINICA
	2016-09-11
卷号	52 期号:9 页码:1133-1141
关键词	soil corrosion pipeline steel disbonded 3PE coating stress corrosion cracking (SCC) cathodic protection
ISSN号	0412-1961
DOI	10.11900/0412.1961.2015.00641
通讯作者	Yan Maocheng(Yanmc@imr.ac.cn)
英文摘要	The three-layer polyethylene (3PE or 3LPE) coatings have been widely used on long-distance high pressure transmission pipelines in China. The 3PE coating tends to remain high insulating after disbonding from pipelines, and block the function of cathoidc protection (CP), similar to PE tape coatings that caused stress corrosion cracking (SCC) failure of pipeline. Disbondment 3PE coatings have been reported worldwide. Because of the high integrity and dielectric strength of 3PE coatings, SCC under disbonded 3PE coating becomes an important issue for integrity management and operation of high pressure pipelines. A great deal of researches have been conducting over the past 20 years to reproduce SCC of high strength low alloy (HSLA) pipeline in laboratory. Most of these studies were conducted in bulk solution condition. The methodology neglects particularity of the thin-layer electrolyte under disbonded coating which has been identified as one of the primary environmental factors related to SCC. In this context, a research project has been initiated on this subject. The overall goal is to systematically investigate corrosion scenarios and mechanochemical interaction of HSLA pipeline steels under disbonded 3PE coating in different soil environments, particularly to further mechanistic understanding the initiation of SCC on pipelines under disbonded coating. In this work, SCC behavior of API X80 pipeline steel under disbonded coating with defect was investigated in acidic soil solution by a crevice cell specially designed for simulating coating disbondment. The crevice cell was equipped with a multi-sample loading frame, through which multi specimens in the crevice cell can be loaded simultaneously. Electrochemical impedance spectroscopy (EIS) was applied to characterize local electrochemical process of the tensile specimens. Local environment parameters (potential and pH) were monitored by microelectrodes. Surface morphology of the corrosion specimens indicate that corrosion intensity of X80 steel decreased over the distance from the opening. Intensive anodic dissolution and microcrack initiation were preferential at the opening defect, whereas corrosion was markedly mitigated under disbonded coating. CO2 content gradient is proposed for the special corrosion scenarios under coating disbondment.
资助项目	National Natural Science Foundation of China[51131001] ; National Research and Development Infrastructure and Facility Development Program of China[2005DKA10400]
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000383635700013
资助机构	National Natural Science Foundation of China ; National Research and Development Infrastructure and Facility Development Program of China
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/122722]
专题	金属研究所_中国科学院金属研究所
通讯作者	Yan Maocheng
作者单位	Chinese Acad Sci, Inst Met Res, Environm Corros Ctr, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Yan Maocheng,Yang Shuang,Xu Jin,et al. STRESS CORROSION CRACKING OF X80 PIPELINE STEEL AT COATING DEFECT IN ACIDIC SOIL[J]. ACTA METALLURGICA SINICA,2016,52(9):1133-1141.
APA	Yan Maocheng.,Yang Shuang.,Xu Jin.,Sun Cheng.,Wu Tangqing.,...&Ke Wei.(2016).STRESS CORROSION CRACKING OF X80 PIPELINE STEEL AT COATING DEFECT IN ACIDIC SOIL.ACTA METALLURGICA SINICA,52(9),1133-1141.
MLA	Yan Maocheng,et al."STRESS CORROSION CRACKING OF X80 PIPELINE STEEL AT COATING DEFECT IN ACIDIC SOIL".ACTA METALLURGICA SINICA 52.9(2016):1133-1141.