J55油管腐蚀失效分析

借助于金相显微镜、扫描电子显微镜对J55油管腐蚀失效原因进行了分析。认为，油管失效是由于微电池腐蚀造成的，腐蚀先在钢管外表面能构成电池回路的珠光体晶粒中进行，然后逐渐扩展到周围的晶粒。     

腐蚀油气管线的可靠性分析

ASME B31G是国际通用的评价腐蚀管线失效应力的标准,考虑到这种方法的保守性,以修正后的B31G模型作为研究腐蚀管线失效应力的基础,考虑管壁厚度、腐蚀速率、工作压力、缺陷深度等随机变量,构建腐蚀油气管线可靠性极限状态函数。然后,采用一次二阶矩法对腐蚀管线进行可靠性分析,得出管线的失效概率、可靠性指标以及剩余使用寿命。此外,为了更加规范的管理腐蚀管线,参照美国石油组织的相关规定,对不同失效概率的管线进行了等级划分。在最后的案例分析中,还讨论失效概率对不同变异系数对的敏感性,计算结果表明失效概率对管壁厚度的变异系数最为敏感。     

芬特过滤器失效分析

采用宏观、微观检验及化学分析等方法对芬特过滤器失效原因进行了分析。分析结果表明，芬特过滤器的衬网材质存在多种缺陷，在含有腐蚀离子的葡萄糖水溶液中，易形成电化学腐蚀，导致衬网丝腐蚀最严重，最终使过滤器因衬网丝腐蚀破坏而失效。     

湿式研磨铝矿低铬铸铁磨球的失效分析

采用扫描电镜等方法对温式研麻铝矿用低铬铸铁磨球失效进行了分析。结果表明，磨球失效原因系强碱腐蚀与冲击磨损的综合作用，而腐蚀所起的作用更为重要。     

蒸馏装置常顶换热器失效分析

采用化学成分分析、宏观和微观分析等方法对失效常顶换热器进行了分析。结果表明：换热器材质成分符合设计要求，由于常顶系统结垢，发生了严重的垢下腐蚀导致穿孔。建议加强系统缓蚀剂置换工作、增加常项注水量及加强水质管理工作，以控制并降低系统腐蚀。     

船舶冷却系统铜镍合金管腐蚀穿孔原因

采用体视显微镜、金相显微镜、电子探针等分析测试方法对腐蚀穿孔失效的BFe10-1.6-1铜镍合金管进行失效分析。结果表明：失效管的内壁存在不同程度的划痕，且腐蚀坑内壁显微组织呈现“波纹”状，符合海水冲刷腐蚀的特征；腐蚀区的显微组织呈现“冰糖块”状，符合晶间腐蚀的特征；腐蚀坑内的泥沙沉积致使管道发生点蚀。结合船用铜镍合金管的使用工况，确认该失效管腐蚀穿孔失效的主要原因是海水冲刷腐蚀、晶间腐蚀及点蚀。     

HK40高温炉管泄漏分析

对制氢炉炉管ＨＫ４０泄漏失效进行了分析，得出，该炉管的失效主要是由Ｈ２Ｓ和Ｃｌ应力腐蚀造成的，为防止这类失效提出了建议。     

压力设备腐蚀失效案例统计分析

收集整理近年来有关压力容器管道的腐蚀失效案例,并对其进行了归纳与分析.从整体的腐蚀情况来看,应力腐蚀及其它应力作用下的腐蚀失效形式是压力容器管道比较突出的腐蚀失效问题,同时奥氏体不锈钢、碳钢及低合金钢三种材料的腐蚀失效较严重.     

酸性气田钻具常见失效形式

近些年来,随着酸性气田的不断勘探开发,钻具失效事故时有发生,阻碍了天然气的安全高效开发。在全面分析了酸性气田开发中存在的各种腐蚀环境后,对酸性气田中普遍存在的氧腐蚀、二氧化碳腐蚀和硫化氢腐蚀三种腐蚀失效机理进行了分析;并通过具体的酸性气田开发中出现的钻具失效案例,分析了钻具在氧气、二氧化碳和硫化氢三种不同的酸性腐蚀环境下的裂纹萌生与扩展特点以及失效形式;最后提出了预防钻具腐蚀失效的措施,对预防和减少酸性气田开发中钻具失效事故的发生具有指导意义。     

循环水冷却器管束腐蚀穿孔失效分析

采用宏、微观分析、化学成分分析等手段，对冷却水管的腐蚀穿孔进行了失效分析。结果表明，水冷却器管束腐蚀穿孔主要是由于材料不合格造成的，冷却水在管内严重结垢给材料产生垢下腐蚀提供了条件。     

G105钻杆腐蚀失效分析

采用金相分析并结合X射线衍射、扫描电镜和电子探针能谱分析等方法，分析了某油田G105钻杆的腐蚀失效原因。结果表明，因腐蚀产物脱落造成井下堵水眼事故，而钻杆停钻后因未及时清理泥浆而造成钻杆内表面附着泥浆，含有氯离子的泥浆加速了其对钻杆的氧腐蚀。就停钻腐蚀问题提出了预防措施。     

电子显微分析技术在奥氏体合金应力腐蚀开裂研究领域中的应用

奥氏体合金广泛应用于核电领域。应力腐蚀开裂是核电材料主要的失效形式之一,奥氏体合金的应力腐蚀开裂关系到核电站的安全运行。综述了评估应力腐蚀开裂的试样方法以及运用现代电子显微分析技术表征应力腐蚀开裂的方法。对这些电子显微分析技术的优点进行了总结,并指出未来电子显微分析技术在应力腐蚀开裂研究中的发展方向。     

Microporous corrosion behavior of gold-plated printed circuit boards in an atmospheric environment with high salinity

The microporous corrosion is the main surface failure mechanism of gold-plated components. The microporous corrosion behavior of electroless nickel and immersion gold (ENIG)-plated printed circuit boards (PCBs) in Turpan area which has an atmospheric environment with high salinity was investigated via a field exposure method for 24 months, as well as 3D analysis, FIB technology, composition analysis, and electrochemical impedance spectroscopy and corrosion mechanism model. After 6 months of exposure, the corrosion products filled up the pores and clustered on the surface as mound shape, and a possible corrosion mechanism model was displayed in the study after 24 months of exposure. The results showed that PCB-ENIG mainly suffered microporous corrosion in a high salinity atmospheric environment. The pores on the gold-plated coating were location where corrosion occurred first and the corrosion products were mostly oxides, chlorides, sulfates and carbonates of copper and nickle.     

Failure analysis of the outside coating on the process roller

A failure case of the outside coating on the process roller is presented in this study. The coating consists of WC-Co, which is deposited on 45 steel by High Velocity Oxygen Fuel (HVOF) spraying. The spalling of coatings has been found in the middle of the roller. Rust was also observed on the coatings of the roller. The failure analysis of the coating was performed in terms of composition analysis, and microstructure observation etc. In addition, the effects of sandblasting post-treatments were compared on the residual sand on the interface between the coating and substrate. And the effect of substrate material is investigated on the corrosion of coatings. It was concluded that the sandblasting particles remained on the substrate surface have effects on the failure of the coating. The peeling-off coating on the roller is also related with the formation of iron oxides. Less sand can be remained on the substrate surface when air purging and brushing is used after the sand-blasting compared with only air purging or non-treatment is applied. The stainless steel shows excellent corrosion resistance than the low carbon steel when they are used as substrate for WC-Co coatings during the wet/dry cyclic corrosion tests.     

水泥窑余热锅炉管屏穿孔失效分析

某水泥窑余热锅炉投运仅两个月,其中压蒸发器最上层管屏弯头处已累计发生了3次穿孔泄漏事故。采用化学成分分析、力学性能测试、宏观分析以及扫描电镜分析等方法,对管屏穿孔失效的原因进行了分析。结果表明：造成管屏穿孔的主要原因是由于该中压蒸发器管屏局部工作介质循环不畅造成管屏弯头处发生气蚀,继而引发冲蚀以及可能伴随的氧腐蚀等一系列减薄行为,它们共同作用造成管屏壁厚不断减薄,最终发生穿孔失效。     

Water chemistry and processing effects on the corrosion degradation of copper tubing in cooling water systems

Specimens of copper tubing from an industrial scale chiller were subjected to a complete corrosion failure analysis. Nondestructive inspection of the tubing indicated substantial corrosion damage and provided the impetus for the corrosion analysis. By application of the typical methods encountered in metallurgical failure investigations, as well as additional chemical analysis techniques, the most probable cause of failure was identified to be a change in the water chemistry during the service life of the tubes. Additional items that may have contributed to the failure include the geometric design of the tube and the post-manufacture cleaning process prior to service. Recommendations were made regarding water treatment and the requirements for any replacement tubes. In addition to discussion of the specific failure(s) investigated, notes regarding the general procedures for corrosion failure analysis are also presented.     

CO2局部腐蚀测试及评价方法

局部腐蚀测试及评价一直是困扰腐蚀界的一大难题.针对CO2局部腐蚀的特征,研发了一种测量CO2局部腐蚀的测试仪.它能准确测定局部腐蚀的有关几何参数,定量评定局部腐蚀的破坏程度,并根据CO2局部腐蚀的特征,建立一种评定CO2局部腐蚀的方法.     

基于点蚀的316L不锈钢在酸性气田环境中的适应性评价

国内外酸性气田的开发使腐蚀环境越来越苛刻,为满足气液混输的工艺要求,发展了耐蚀合金/碳钢的双金属复合管技术。316L不锈钢被广泛用于双金属管的内衬,在含H_2S和CO_2环境中腐蚀速率很低,然而在高含Cl-的溶液中,316L不锈钢容易出现点蚀而诱发集输管线失效,为此,就316L不锈钢在酸性气田集输环境中的点蚀进行评述。讨论了影响316L不锈钢点蚀的材质因素,Mn和Fe的硫化物及Mg、Al、Ca的氧化物等两种夹杂物均能促进钝化膜的溶解而引起点蚀;分析了316L不锈钢点蚀的H_2S、CO_2、温度、Cl-浓度和pH值等环境的适应性条件,发现H_2S环境比CO_2环境更容易发生点蚀,H_2S和CO_2对点蚀发生存在协同机制,温度升高、Cl-浓度增加和酸性介质均会增加316L不锈钢点蚀的敏感性。为进一步优化选材原则,需重点加强环境因素的协同机制、环境适应性的边界条件、点蚀发展的动力学以及新的标准研究。     

Top of the REAC tube corrosion induced by under deposit corrosion of ammonium chloride and erosion corrosion

The crystal and deposition behavior of ammonium chloride salt (NH₄Cl) and multiphase flow simulation were investigated by using Aspen software and CFD technology. And the corrosion failure causes of inlet tube explosion of a refinery hydrocracking reactor effluent air cooler (REAC) were studied. The top of 10# carbon steel base tube corrosion is severe, and reveals an inhomogeneous thinning. The field with localized corrosion is mainly distributed in a range of approximately 1.5 m away from the liner tube. The NH₄Cl crystal temperature increases with the increase of feedstock chloride content, and the decrease of injected water volume. The NH₄Cl salt granules mainly distribute in the forepart of an inlet tube of the REAC system. The liquid phase mainly exists in the bottom of an inlet tube, and the gas phase in the top of the tube. Without the enough liquid water, the NH₄Cl in the gas phase crystallizes and deposits on the top of a pipeline, resulting in under deposit corrosion, which interacts with the flow erosive action accelerates the localized corrosion thinning at the top of forepart of an inlet tube. Outside of the range of corrosion failure, the possibility of ammonium salt crystal decreases with decreasing temperature, and the condensed water increases gradually, then the deposited ammonium salts completely dissolve, and reduces the corrosion of downstream system.