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某输油管道腐蚀泄漏失效原因分析 总被引:1,自引:0,他引:1
目的分析输油管道腐蚀泄露失效的主要原因。方法对输油管道泄漏失效进行了深入调查研究,分析了输油管道失效样品,对泄漏孔形貌、几何参数、理化性能、金相组织进行了试验分析,并在泄漏穿孔处取样进行了电子显微镜扫描、微区能谱分析。结果经化学分析、力学性能和金相组织等理化检验分析,该失效输油管道的材料理化性能符合GB/T 8163—2008标准的相应要求及用户要求。从穿孔宏观形貌分析来看,腐蚀区域面积较大,管道内壁存在大量腐蚀产物,穿孔位于输送管道的下部,最大腐蚀深度达3.5 mm,且管道中存在大量临界腐蚀坑电子显微镜下放大观测,能看到表层覆盖有疏松的腐蚀产物,微区能谱分析显示腐蚀产物中含有大量的Cl、C、O和Fe等元素。结论材料性能并不是造成输油管道失效事故的主要原因,输油管道泄漏主要是由管体内壁点腐蚀穿孔造成的,引起腐蚀穿孔的主要因素为输送流体介质中的Cl-,当管材基体中的Fe不断被Cl-腐蚀溶解后随流体介质迁移,点蚀坑迅速扩展,最终导致腐蚀穿孔。 相似文献
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《热处理技术与装备》2017,(6)
某石油化工厂输油管道使用过程中发生穿孔失效现象。采用宏观、微观检验、化学成分分析及压扁试验等方法,对失效管件进行了检测。结果表明管件表面大量的非金属夹杂物与基体形成原电池,继而发生电化学腐蚀,形成显微腐蚀点。这些腐蚀点成为凹坑形成的原因,在应力作用下,这些显微腐蚀点会继续进行应力腐蚀,直至穿孔管道穿孔失效。 相似文献
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目的针对某油田316L/L360NB机械式双金属复合管的穿孔问题,开展失效行为及原因分析,为此类管道的失效控制提供理论依据。方法基于此失效管样的生产标准和服役工况,通过宏观检查、无损检测、化学成分分析、金相组织分析、硬度分析、扫描电镜及能谱分析等方法,结合焊接工艺规范,综合分析其穿孔失效原因。结果该失效管样的316L衬管和L360NB基管外径、壁厚、化学成分和硬度均符合相关标准要求,金相组织未见异常。其封焊已焊穿衬管,金相组织为马氏体,未见其他焊接缺陷。点蚀均发生在封焊,腐蚀产物的主要化学元素为C、O、Fe,并含有少量的Cl。316L衬管未见腐蚀,封焊区的耐蚀性最差。结论该双金属复合管的失效行为是局部内腐蚀穿孔,失效原因是由于不当的封焊操作致使封焊焊穿衬管,导致耐蚀性较低的封焊在高Cl-腐蚀环境中发生点蚀。封焊腐蚀穿透后,衬管与基管构成电偶腐蚀,使得耐蚀性差的碳钢基管迅速腐蚀穿孔。建议对机械式双金属复合管采用堆焊耐蚀性更好的焊材进行管端封口,以有效防止失效的再次发生。 相似文献
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铝土矿酸介质中铁的行为 总被引:4,自引:1,他引:4
研究了高温高压条件下铝土矿中铁在硫酸介质中的溶解行为,结果表明:在一定的温度条件下,铝土矿的赤褐铁矿能较好地溶于硫酸溶液中,而铝土矿中含铝矿物的性质不发生变化,从而为铝土矿的进一步加工利用提供了条件。详细讨论了反应温度、反应时间、硫酸浓度、液固比等因素对铁的溶解行为的影响,得出了在最佳工艺条件,即在反应温度160℃、反应时间3h、硫酸浓度0.7mo1/L和液固比6:1时除铁效率最高。 相似文献
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Progress in application of rare metals in superalloys 总被引:1,自引:0,他引:1
Rare metals play an important role in development of superalloys. Over the last two decades, the application of the rare metals in superalloys has achieved progress significantly. They present multi-beneficial effects for strengthening the matrix and the c0phase, increasing the lattice misfit, cleaning the grain boundary, improving the carbides and eutectics, refining the grain, stabilizing the oxidation film, etc., so that the elevated temperature rupture life and elevated temperature oxidation resistance are improved significantly, leading to a broad application in the superalloys. In order to meet the higher demand for better superalloys in the future, more intensive research is necessary on the effects of the rare metals on the superalloy, and especially on the combination effect of various rare metals and mutual influence among them. Utilization of the computational materials science and combinatorial high throughput experiment will be of importance in application of rare metals in superalloys. 相似文献
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none 《腐蚀工程科学与技术》2013,48(1):53-56
AbstractThe effect of sulphides on the corrosion of zinc in artificial sea water has been studied over the pH range 6·5 to 8·6. A comparison of the weight loss and potential values of specimens in aerated and deaerated sea water, with or without the addition of sulphide, has shown that at pH values > 7·2 the presence of sulphides increases the corrosion, while at lower pH values it is partially inhibited. This is related to changes in the concentration of S2- ions in the solution. The corrosion products formed in the more corrosive solutions were shown to consist mainly of ZnS, which is believed to cause loss of adhesion of the corrosion products on the zinc surface, and thus to accelerate the corrosion. 相似文献
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The effect of anomalies detected in x-ray diffraction and metallographic examination of welded joints on the properties of resistance butt welded joints in 1201 aluminium alloy is determined and recommendations are given for the standards for permissible defects. 相似文献
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Ag—Cu—Ti钎料中Ti元素在金刚石界面的特征 总被引:18,自引:2,他引:16
研究了金刚石钎焊接头中碳化物形成元素Ti与金刚石(或石墨)之间的相互作用行为。通过对接头界面处的成分分布和断口形貌观察,分析了Ti的作用机理、新生儿合物TiC的断口形及生长规律,结果表明:在一定的条件下,Ti元素与组成金刚石(或石墨)的碳元素发生反应形成TiC层;碳化物层使钎料与金刚石之间产生冶金结合;TiC与金刚石之间存在有明显的界面,TiC断口的微观表面形态呈韧窝状;在金刚石表面初始形成的TiC的生长方向与金刚石的晶向指数有关。 相似文献
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目的: 评价湖南省人民医院院区2016年利奈唑胺临床应用的合理性及有效安全性,为其临床应用提供参考。方法: 采用回顾性研究,利用医院信息管理系统调取2016年使用利奈唑胺患者病例资料,设计调查表,统计用药合理率,分析不合理原因;计算临床治愈率,病原菌清除率及综合治愈率;监测用药前后红细胞、血红蛋白、血小板下降程度。结果: 利奈唑胺临床应用合理率为48.1%,不合理原因主要是适应症把握不准确及疗程不合理;临床有效率为40.4%,病原菌清除率为42.3%,综合治愈率为56.4%;骨髓抑制发生率为21.2%,发生的平均年龄为(81.4±8.7)岁,平均用药时间为(13.6±5.6) d。结论: 我院区利奈唑胺临床应用合理性有待提高,正确把握适应症和疗程将很大程度提高合理率;综合疗效尚可,老年患者需特别注意骨髓抑制的发生。 相似文献
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S. J. Drew M. A. Mannan K. L. Ong B. J. Stone 《International Journal of Machine Tools and Manufacture》2001,41(4)
Most investigations of chatter have made the assumption that torsional vibration is not a significant factor. Some recent work has shown that chatter in grinding is affected by a change in the torsional stiffness of the workpiece drive. Also, a theoretical model of grinding chatter has been developed that confirmed the significance of torsional effects. However, the model for the grinding force was assumed to be a dynamic equivalent of a published steady-state model. This paper describes tests conducted to measure the variation in force caused by an oscillation in workpiece speed. The oscillating test results indicate that the torsional vibration of the workpiece may well be a significant effect on chatter in grinding. Moreover, as the grinding force changes with workpiece speed, it may be possible to use variation of workpiece speed at high frequency to reduce chatter. 相似文献
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Abstract Flash welding, through conferring a number of important advantages, such as high productivity, good-quality welds, and suitability for welding of components with large cross-sections, is extensively used for shop welding of rails, plating of hot coils, welding of wheel rims, etc.1–3 More compact welding facilities are also being sought through further exploitation of mechanical control technology for practical applications in job-site welding of rails, H-steel sections, etc.4 相似文献
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