BFe30-1-1白铜管在海洋大气环境中的腐蚀行为

采用激光拉曼光谱仪结合扫描电镜、X射线能谱仪等研究了BFe30-1-1白铜管在海洋大气环境中暴露20年的腐蚀情况,对试样去除腐蚀产物前后表面的元素分布及其存在形式进行了分析.结果表明,表面腐蚀产物是CuO、α-Fe2O3和Fe3O4;用石英玻璃刮掉表面一层腐蚀产物后检测到了NiO2并且此时氯元素的含量较高.将原始腐蚀样品酸洗后,检测到Cu2O、FeO和γ-Fe2O3,并且检测到了较高含量的碳元素.试验结果还表明,激光拉曼光谱仪和能谱仪联用可以很好地评价白铜管的大气腐蚀行为.     

渤海某油田L80油管腐蚀机理研究

目的研究渤海某油田L80油管腐蚀机理,对分析该油田油管腐蚀特点、确定油管腐蚀类型、证实井底腐蚀环境、评估油管腐蚀程度和推荐油管防腐材质具有重要意义。方法基于L80油管宏观腐蚀形貌观察做出的初步判断,首先进行材质分析,其次进行微观腐蚀形貌分析,然后进行腐蚀产物分析,再进行腐蚀程度分析,最后进行电化学试验。结果该L80油管理化性能及金相组织符合标准,其内外壁腐蚀行为不一致,外壁以均匀腐蚀为主且腐蚀轻微,内壁有一定程度局部腐蚀且腐蚀较严重。腐蚀产物主要含有Fe、S、O和C元素,主要成分为Fe1-xSx、Fe CO3和Fe_2O_3。其外壁点蚀坑深度在15~50μm之间,内壁点蚀坑深度在80~150μm之间,内壁微裂纹宽度在20~70μm之间。CO_2分压、H_2S分压、含水率和温度对L80油管腐蚀行为有重要影响。结论该油田井底CO_2和H_2S共存,L80油管发生了CO_2/H_2S共存的电化学腐蚀,但点蚀、应力腐蚀开裂(SCC)整体上比较轻微,且L80油管表现出良好的抗硫化物应力开裂(SSC)能力。根据研究结果,推荐现场可以继续使用L80油管。     

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 通过化学、金相、扫描电镜等系统检测分析,对冷凝器铜管的腐蚀情况进行研究,结果表明：冷凝管铜管穿孔是从内壁向外壁发展并沿晶界腐蚀开裂,属于沿晶界脱锌腐蚀。对冷凝器铜管进行化学清洗和缓蚀剂预膜处理,可以提高铜管耐腐蚀性能。     

铜-低碳钢钎焊接头的耐蚀性评价

通过动态挂片腐蚀实验、宏观和金相组织观察、SEM 及能谱分析等方法对采用Cu-Zn钎料、Ag-Cu钎料、Cu-P钎料钎焊的无氧纯铜-低碳钢管钎焊 接头的耐蚀性能进行了评价分析.结果表明：采用Cu-P钎料时钢和钎缝间出现裂纹，接头遭 受腐蚀后铜管内壁普遍腐蚀，同时钎缝因腐蚀而开裂；Cu-Zn钎缝成型好，但钎缝 本身出现由于金相组织发生选择性腐蚀而引起的局部蚀坑，铜管对应处也出现明显减薄性腐 蚀；Ag-Cu钎料所焊接头成型好，接头各处腐蚀轻微.建议采用Ag-Cu钎料进行铜-低碳钢的 钎焊.     

锅炉水冷壁管内壁腐蚀泄漏原因分析及处理

对某锅炉水冷壁管内壁腐蚀原因进行分析。根据对水冷壁内壁腐蚀产物进行化学元素分析、金相检测、SEM扫描电镜及EDS能谱分析和XRD衍射分析结果,认为腐蚀原因是凝汽器铜管发生腐蚀泄漏,使炉水质量变差。Cu2+在水冷壁内壁表面上沉积,对水冷壁管内壁保护膜产生破坏作用,导致水冷壁管内壁出现点蚀。而炉水处理过程中磷酸盐的加入,促进了Cu等金属元素在内壁的沉积,加剧了腐蚀的进行。水冷壁内壁的腐蚀产物不断生成并附着在内壁上,既造成管壁持续减薄,又影响了管子的传热效果,使管子在运行中一直处于超温状态,组织逐渐老化。管壁的减薄和材质的老化共同导致该管子无法承受内部介质压力而发生泄漏。为防止同类事故再次出现,制定了具体的处理措施。     

锅炉水冷壁管内壁腐蚀泄漏原因分析及处理

对某锅炉水冷壁管内壁腐蚀原因进行分析。根据对水冷壁内壁腐蚀产物进行化学元素分析、金相检测、SEM扫描电镜及EDS分析和XRD分析结果 ,认为腐蚀原因是凝汽器铜管发生腐蚀泄漏,使炉水质量变差。Cu2+在水冷壁内壁表面上沉积,对水冷壁管内壁保护膜产生破坏作用,导致水冷壁管内壁出现点蚀。而炉水处理过程中磷酸盐的加入,促进了Cu等金属元素在内壁的沉积,加剧了腐蚀。水冷壁内壁的腐蚀产物不断生成并附着在内壁上,既造成管壁持续减薄,又影响了管子的传热效果,使管子在运行中一直处于超温状态,组织逐渐老化。管壁的减薄和材质的老化共同导致该管子无法承受内部介质压力而发生泄漏。为防止同类事故再次出现,制定了具体的处理措施。     

除湿机表冷器铜管泄露原因分析及改进措施

铜管是凝热器、表冷器等热交换器的首选管材,某表冷器铜管在投入使用后短时间内发生泄漏。本文对腐蚀铜管和铜管内壁的垢状物进行了化学成分测定,采用OM、SEM和EDS等多种检验手段进行综合分析;同时对循环冷却水进行了水质分析,分析结果表明：吸附在铜管内壁的垢状物,破坏了铜管内壁表面致密的钝化膜,形成原电池效应并产生点蚀,导致铜管发生泄漏;在对泄漏原因分析的基础上,本文提出了改进措施。     

加氢装置不锈钢换热器管失效分析

某加氢装置0Cr18Ni10Ti不锈钢换热器管在服役过程中发生了穿孔。通过化学成分分析、金相观察、宏观和微观腐蚀形貌观察、腐蚀产物分析、工况分析等分析方法,确定了换热管失效的原因。结果表明:失效管段存在两种形貌的点蚀坑,一种点蚀坑相对较小,形貌不规则,另一种点蚀坑相对较大,呈近似半球状,边缘较光滑,部分点蚀坑底部具有沿晶型腐蚀的特征;不规则点蚀坑主要是由连多硫酸腐蚀造成的,而规则状点蚀坑是由连多硫酸腐蚀和氯化铵沉积腐蚀共同造成的,其中后者起主要作用;较大的规则状点蚀坑最终导致失效,由此确定造成某0Cr18Ni10Ti不锈钢换热器管失效的主要原因是氯化铵沉积腐蚀,而连多硫酸腐蚀对失效的发展起到了促进作用。     

AZ91D在模拟体液中的腐蚀机理与矿化分析

为在镁合金表面仿生矿化制备钙磷沉积层,探宛矿化过程中镁合金的腐蚀机理,试验采用压铸镁合金AZ91D为基体,经过HF/乙二醇和高浓度NaOH预处理,在人工模拟体液中浸泡4天、6天、10天及16天,并对沉积层进行SEM和EDS分析.结果表明:AZ91D表面能够通过仿生矿化生成钙磷沉积层;浸泡早期沉积层表面分布蚀坑和网状裂纹,浸泡早期主要以点蚀为主,浸泡后期以全面腐蚀为主;含Cl针状团簇的局部富集和溶解是形成点蚀坑的重要原因;Clˉ的穿透作用使晶界薄弱处形成裂纹开端,析氢引发更多的裂纹生成和扩展;Al元素的溶出和碳酸盐沉积一定程度提高了耐全面腐蚀性能.     

燃煤锅炉用水冷壁管腐蚀失效分析

通过宏观形貌检查、化学成分分析、金相检验、扫描电镜及能谱分析等手段,分析了某发电厂锅炉水冷壁管腐蚀破坏的原因。结果表明:水冷壁管破坏的主要原因是由于外壁高温烟气腐蚀与内壁垢下腐蚀、酸腐蚀共同作用的结果。燃煤中S含量和Cl含量高是引起外壁高温烟气腐蚀的主要因素;内壁存在的元素S和Cl是局部产生点蚀的主要原因。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.