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通过多种测试方法对东临复线输油管道阴极保护系统的检测,发现防腐层老化、漏电点多是该管线阴极保护距离缩短的主要原因.为此,提出了处理方法和预防措施,建议对管道腐蚀与防护系统的技术现状和管道整体安全性进行科学评价. 相似文献
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管线腐蚀与防护势态的灰色评估研究 总被引:3,自引:0,他引:3
分析了影响输油管线防护状态的4项因子即管地电位 、阴极保护电位、土壤中碳钢腐蚀电流密度以及防腐层电阻的统计分布特征,发现它们分别 服从正态分布或对数正态分布;且新旧两条输油管线的管地电位与防腐层绝缘电阻的均值与 方差具有显著性差异,而土壤腐蚀电流密度与阴极保护电位则不构成显著差异.应用灰色决 策(灰靶)理论对管线综合势态和运行风险进行了分级和评估,为减少管道腐蚀事故和管道 的预防性维修提供依据. 相似文献
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For the corrosion protection of natural gas transmission pipelines, two methods are used, cathodic protection and a coating
technique. In the case of cathodic protection, defects are embrittled by hydrogen occurring at crack tips or surfaces of materials.
It is, however, very important to evaluate whether cracks in the embrittled area can grow or not, especially in weld metal.
In this work, on the basis of elastic plastic fracture mechanics, we performed CTOD testing under various test conditions,
such as potential and current density. The CTOD of the base steel and weld metal showed a strong dependence on the test conditions.
The CTOD decreased with increasing cathodic potential and current density. The morphology of the fracture surface showed quasi-cleavage.
Cathodic overprotection results in hydrogen embrittlement at the crack tip. 相似文献
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深海钢铁材料的阴极保护技术研究及发展 总被引:1,自引:0,他引:1
综述深海环境中溶解氧、温度、pH值、碳酸盐及压力等对钢铁材料的阴极保护及钙质沉积层形成过程的影响。对国内外深海钢铁材料的阴极保护研究工作进行总结,介绍深海阴极保护参数的设计及应注意的因素,认为提高初始电流密度和阴极保护联合涂层是深海阴极保护的重要保护措施。最后对现阶段深海阴极保护研究中的不足及发展方向进行探讨。 相似文献
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为了研究3PE防腐蚀层服役过程中的失效问题,采用现场测试、实验室分析和模拟试验等方法对服役中3PE防腐蚀层的剥离问题进行了分析,并对其寿命进行了预测。结果表明:生产过程中表面处理、环氧粉末喷涂等工艺控制不当,服役过程中防腐蚀层破损、阴极保护电位过负等环境因素,均会导致3PE防腐蚀层的剥离;同样的电流密度下,随着时间的延长,阴极剥离距离逐渐增加,且在试验前期增加较快,在试验后期增加变缓;相同时间下,施加的电流密度越高,阴极剥离距离越大,3PE防腐蚀层的特征寿命与电流密度的倒数呈指数关系。 相似文献
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牛丽媛 《中国有色金属学会会刊》2008,18(Z1)
A technology for preparation of a cathodic phosphate coating mainly containing nano metallic zinc particles and phosphate compounds on magnesium alloy was developed.The influence of cathodic current density on the microstructure of the cathodic phosphate coating was investigated.The results show that the crystals of the coating are finer and the microstructures of the outer surface of the coatings are zigzag at the cathodic density of 0.2-0.5 A/dm~2.The content of nano metallic zinc particles in the coat... 相似文献
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J.-W. Kühn von Burgsdorff 《工业材料与腐蚀》1968,19(6):473-478
Internal cathodic protection of salt water pipelines with the aid of platinized titanium anodes In petroleum production heavy corrosion occurs in the salt water injecting or flooding pipelines. This corrosion can be eliminated either with the aid of a passive protection (protective coating) or, better, by means of an active protection, i.e. cathodic protection with impressed current. While short pipelines can be protected economically with rod anodes, a continuous, partially platinized titanium wire anode has proven must successful for long pipelines. Particular attention must be devoted to the problem of the current feed. The current density required for the protection of bare pipeline surfaces is in the order of 150 mA/sq.m. It can be considerably reduced by combining the active protection with a passive protection by a coating. In connection with the problem of a suitable reference electrode for measuring the protective potential in high pressure pipelines, experiments have been carried out to determine the protective current requirements in a stagnant and a flowing electrolyte respectively. Finally the question of the economy of the process is shortly discussed. 相似文献
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与传统的腐蚀保护方法相比,光电化学阴极保护是一种节能、环保、经济的腐蚀防护技术.该技术的关键特征是,利用光电化学阴极保护材料在光照条件下产生光生电子,而光生电子以电势差作为驱动力转移到金属上,并富集在金属表面,导致金属的电位负移,从而实现对金属的强制保护.总结了近年来国内外光电化学阴极保护材料的制备方法与性能特点,针对目前TiO2薄膜材料存在的问题,阐述了通过形貌调控、元素掺杂、半导体复合、异质结构成、材料耦合等方式,提升光电化学阴极保护性能的策略和技术.概括了非TiO2类光电化学阴极保护纳米材料的性能及应用,主要有ZnO、SrTiO3、In2O3、g-C3N4、铋基金属氧化物等半导体材料.明确了近年来光电化学阴极保护材料防腐功能化实现的途径和方法,包括光阳极法和直接涂敷法,并比较了二者之间的优缺点.最后,提出了金属光电化学阴极保护材料及防腐功能化研究的发展趋势及存在的问题. 相似文献
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采用COMSOL Multiphysics软件,对管道极化电位和管地电位进行模拟计算,从套管有涂层和无涂层的两个方面,研究了涂层孔隙率对套管处埋地管道的阴保电位影响规律。结果表明:套管内管道涂层质量越差,管道所需的极化电流就越多,管道的阴保效果就越差;加涂层套管在环形空间内的电位比无涂层套管的更正,但在地表处却稍微偏负,所以仅仅依靠管地电位来判断管道的极化电位是有误差的;当套管无涂层时,只要环形空间内有电解质,其对管道的极化电流无屏蔽作用,所以利用密间隔电位测量(CIPS)、直流电压梯度法(DCVG)和交流电压梯度法(ACVG)等地面检测方法可以判断出套管内管道防腐层的质量和阴极保护的等级状况。 相似文献