集输管内腐蚀失效原因分析

对某站原油外输管线的内腐蚀穿孔管段进行了取样分析,使用光学显微镜、X射线衍射仪、能谱分析仪等设备对管子腐蚀形貌进行观察,发现腐蚀产物中有不同类型的羟基氧化铁以及FeCO3和FeS等,分析了导致管子电化学腐蚀穿孔的主要原因,对杂散电流和氯离子加速腐蚀穿孔的机制进行了深入的探讨,并对该类腐蚀防护提出了建议。     

某油气田原油生产管汇腐蚀失效原因分析

某油气田原油生产管汇的背弯部分有明显减薄。通过对该生产管汇宏观形貌、材料成分、超声波测厚等的分析,并观察和分析了生产管汇腐蚀形貌和腐蚀产物,结合生产管汇的工况条件,对该生产管汇的失效原因进行了分析。结果表明:生产管汇腐蚀失效主要是由于冲蚀和垢下腐蚀共同作用引起的。     

铝合金木纹型材腐蚀失效原因分析

为了查明木纹型材的失效原因,利用电子探针、金相显微镜、能谱仪、直读光谱仪等对腐蚀穿孔失效的6063铝合金木纹型材进行分析。结果表明:由于木纹型材表面长时间与潮湿的砂浆接触,使得碱性溶液能够透过木纹型材带有微观缺陷的表面涂层而腐蚀铝合金基体,最终使得木纹型材发生腐蚀失效。     

喷淋式冷凝器在宝钢2RH真空系统中的应用

冷凝器是真空排气系统中一个很重要的组成部分,本文主要分析了宝钢2RH真空系统喷淋式冷凝器的结构特点和工作原理;运用数学建模的方法,建立基于液滴受力分析的数学模型,以及在生产现场使用中的一些不足和相应的改进措施.     

二氯乙烷管线腐蚀失效分析

采用宏观分析,金相分析,硬度检测,扫描电子显微镜分析,能谱分析及X射线衍射分析等多种方法对某氯碱厂二氯乙烷输送管线爆裂泄露的原因进行综合分析。结果表明：管线三通处介质流向发生突变,使管壁受到严重的冲刷腐蚀作用,是管线失效的主要原因。物料中含有水分,与二氯乙烷反应得到氯化氢,加剧管线腐蚀。钢材本身存在一定的冶金缺陷易引发局部腐蚀。Cl^-在腐蚀坑处富集可加剧局部腐蚀。     

套管腐蚀失效分析

采用能谱，电子探针及Ｘ衍射方法对文１０１－１井套管腐蚀产物进行了元素，组成与结构分析。结果表明，贯穿全井的腐蚀产物有ＣａＣＯ２，ＦｅＣＯ３，Ｆｅ９Ｓ８和ＦｅＳ且套管井深１０００ｍ以上部位的硫化物主要是Ｆｅ９Ｓ８，１０００ｍ以下部位为ＦｅＳ。为探针套管腐蚀失效“上重下轻”提供了科举依据。     

宝钢IBF循环水地下水管环境腐蚀状况分析

根据宝钢ＩＢＦ循环水地下水管的特点，结合国内外防止环境腐蚀（土壤、水介质）的方法与经验，选用土壤腐蚀多项指标综合评价法及水介质均匀腐蚀的十级标准等分析方法，通过测定地下水管周围土壤及水介质的理化性质，对宝钢ＩＢＦ循环水地下水管环境腐蚀状况进行了初步分析与评价。     

RH真空精炼吹氩喷嘴结构参数对循环流量影响的数值模拟

循环流量是判断RH真空脱气装置精炼效率的重要指标之一.本文针对某钢厂180t RH真空精炼装置,基于计算流体动力学(CFD)方法,建立了RH真空精炼过程中气泡驱动的气-液两相流动理论模型,并利用CFD商业软件FLUENT进行数值模拟,探讨了相同真空度下吹氩喷嘴分布形式、喷嘴排间距等参数对循环流量的影响.结果表明:相同真空度和吹氩流量条件下,相比于单排圆周均布形式,喷嘴双排圆周交错分布时的循环流量更大、精炼效率更高,并存在最优的排间距,可作为RH真空精炼操作参数优化及工程结构改进的参考.     

某天然气管线腐蚀穿孔失效分析

为了解决某天然气输送管线的腐蚀穿孔失效问题,确定造成输气管道腐蚀失效的主要因素,采用扫描电子显微镜、EDS、XRD等分析方法,对某天然气输送管线失效位置进行了宏观形貌、微观形貌、材质及腐蚀产物等的分析研究.结果表明:失效管段处于低洼易积水处,局部腐蚀及穿孔主要发生在6点钟方向.通过元素成分分析和力学性能分析,确定管线材...     

方坯连铸RH真空装置真空泵控制系统

介绍攀钢方坯RH精炼装置真空系统基本控制功能,侧重介绍真空泵系统的功能和其相关系统控制.     

宝钢4#RH高效水环泵-蒸汽喷射真空泵系统的应用实践

介绍了宝钢一炼钢4#RH中投入的水环泵和蒸汽喷射真空泵的组合泵形式的应用,描述了这个1500 kg/h真空泵系统的没备布置和技术参数,并给出了实际的运行模式和最终的性能测试结果.最后强调了其节能经济效益非常显著.     

Failure analysis of maraging steel fasteners used in nozzle assembly of solid propulsion system

Owing to high strength and better toughness, maraging steels are being widely used for aerospace application. In one such application, maraging steel was used to fabricate fasteners for nozzle assembly of propulsion system. Few fasteners were found broken during second stage of torque application. Failure was at head/shank junction in each of the three failed fasteners. Detailed metallurgical investigation revealed that the fasteners were under assembly load and exposure to severe corrosive environment. Crack originated from the thread root, propagated intergranular mode with tree root morphology. Considering such evidences, it was inferred that the failure occurred due to stress corrosion cracking.     

Numerical analysis of spontaneously condensing phenomena in nozzle of steam-jet vacuum pump

The primary fluid in a steam-jet vacuum pump is not assumed as a perfect gas as general research in the present study. A mathematic model based on the wet steam model for transonic flow is proposed to investigate the flow behaviours of primary fluid in the nozzle of a steam-jet vacuum pump. The simulation based on a wet steam model was carried out to predict the flow characteristics of primary fluid along the nozzle axis by a commercial computational fluid dynamics (CFD) code (FLUENT6.3). The simulation results showed that there was spontaneous condensation as the supersonic flow passing through the nozzle and the simulation results had a good agreement with the experimental data. It is found from the numerical simulation results that the steam flow characteristics in nozzle are quite different from a wet steam model and a perfect gas assumption: the outlet pressure of the nozzle predicted in the present study is higher than that as the primary fluid assumed as perfect gas, the outlet velocity is about 10% lower than that as the primary fluid assumed as a perfect gas, and the temperature at the outlet of the nozzle is much higher than that as the primary fluid assumed as a perfect gas. The simulation results demonstrate that the thermo-positive process due to steam condensation would hinder the supersonic expanding flow process in nozzle and depress the efficiency of the nozzle which would affect the pumping performance of steam-jet pump.     

可编程控制器在真空干燥与浸渍设备中的应用

本文主要介绍了可编程控制器及智能温控仪在真空干燥与浸渍设备中的应用,并介绍了应用出现的问题及解决办法。     

Residual gas analysis in the TOF vacuum system

The residual gas composition in the time-of-flight (TOF) spectrometer vacuum system has been measured with a quadrupole mass spectrometer. All residual gases except hydrogen and helium are condensed and freezed on the windows of the liquid hydrogen target. As a result it increases the background during the reaction between the cooler synchrotron (COSY) beam and the target. These condensates have to be cleaned from the target windows by fast heating the target cell from 16 K up to room temperature. The partial pressure spectrums of the condensed gases on the liquid hydrogen target are also measured. The residual gas analysis shows that the majority of the condensates on the target windows are nitrogen, oxygen and water vapor. The target area has to be in a high vacuum <1×10⁻⁶ mbar in order to minimize the condensate. The target windows have to be cleaned with the fast heating cycle every 48 h.     

Status of the cyclotron vacuum system at TRIUMF

The world's largest cyclotron was built at TRIUMF in 1972 and commissioned to full energy in 1974 [Harwood VJ, Yandon JC. TRIUMF Design Note, TRI-69-7, 1969 [1], Blakely RG, Moore RW, Harwood VJ. TRIUMF Design Note, TRI-69-9, 1969 [2]]. The cyclotron accelerates negatively charged hydrogen ions up to 500 MeV, and protons are produced by inserting a stripping foil in the beam which removes two electrons from each negatively charged hydrogen ion and allows the remaining bare protons to be channeled out of the accelerator. By making these protons strike different kinds of targets, intense beams of neutrons, pions and muons can also be created, thus making possible many different experiments. The volume of the cyclotron vacuum tank is about 100 m³ and operates at 2×10⁻⁸ Torr pressure during beam production. Most of the vacuum is achieved by cryopumping with a B-20 cryogenerator and six cryopumps. The B-20 is a Stirling cycle refrigerator, which supplies helium gas at 16 and 70 K to the cryopanels in the tank. The tank is also equipped with two turbo pumps. The vacuum system went through a few modifications during more than 30 years of operation. This paper presents the status of the cyclotron vacuum system and discusses the latest upgrades.     

The Veterans Affairs root cause analysis system in action

BACKGROUND: The patient safety program in the Department of Veterans Affairs (VA) began in 1998, when the National Center for Patient Safety (NCPS) was established to lead the effort on a day-to-day basis. NCPS provides the structure, training, and tools, and VA facilities provide front-line expertise, feedback about the process, and root cause analysis (RCA) of adverse events and close calls. MONITORING THE PROCESS: Facility patient safety managers determine the disposition of adverse events and close calls occurring at their facilities. They use a safety assessment code (SAC) to prioritize the actual and potential severity and frequency of an event. BEFORE-AND-AFTER STUDY: Before the new RCA system was implemented in 2000, the VA used another adverse event reporting system, focused review (FR). A comparison of the two processes indicates that the RCA process has shifted analyses of adverse events toward a human factors engineering approach-entailing a search for system vulnerabilities rather than human errors and other less actionable root causes. CASE EXAMPLES: Two case examples--on hazards in the magnetic resonance imaging (MRI) room and on a cardiac pacemaker malfunction--illustrate how the RCA system works in actual operation. The cases illustrate that broadly applicable, high-impact actions can result from a thorough RCA process. DISCUSSION: NCPS monitors the quality and completeness of RCAs through the immediate review and feedback process. Still to be investigated is the effectiveness of RCA actions addressing the hypothesized root causes and contributing factors of the close calls and adverse events.