金属给水管道的腐蚀控制措施分析

金属给水管道在现代社会的工作领域应用非常广泛,为社会的发展作出了巨大贡献。金属给水管道在经过长时间的运行后很容易出现严重的腐蚀现象,这对金属给水管道的正常运行有很大的影响。本文主要对金属给水管道的腐蚀机理以及金属给水管道腐蚀现状进行了分析,并在此基础上提出了一些金属给水管道腐蚀控制措施。     

埋地金属管道腐蚀穿孔原因与防护策略

金属管道常年埋在地下,受到各种因素影响会导致腐蚀情况发生。本文从外腐蚀和内腐蚀两个方面对埋地金属管道腐蚀穿孔的原因进行了分析,并对金属管道腐蚀穿孔的防护策略进行了探讨,对防止或减缓埋地金属管道腐蚀具有一定的作用。     

大庆油田北过地区埋地金属管道腐蚀状况分析

大庆油田北过地区位于萨北油田北部过渡带．地势低洼，土壤环境较差，致使该地区各种埋地金属管道腐蚀穿孔严重。给正常生产带来较大危害。通过对北过地区土壤环境、在用站-井网管道结构性能、施工现场、生产使用情况进行对比分析。将对该地区以后站-井网埋地金属管道的设计选材与管理提供参考。     

阴极防腐保护远传远控智能系统现场试验

防腐层加阴极保护是埋地金属管道和储罐的最基本做法,在油田建设中阴极保护是重要的防腐蚀手段,能够减缓或降低埋地金属的腐蚀,保证埋地管道和储罐长期稳定运行,减少因腐蚀穿孔而影响正常生产和财产损失,延长埋地管道和储罐的使用寿命.我厂现有92套阴保系统,承担着全厂1000立以上的储罐和部分站间管道的防腐保护.     

埋地金属管道腐蚀穿孔原因分析及防护探讨

金属埋地管道长期在地下深埋的环境下运行,因此,对埋地管道的腐蚀情况的影响因素也比较多。本文主要的从埋地管道的外表面腐蚀以及内壁腐蚀两个角度对金属管道的腐蚀穿孔的原因展开了分析,并针对具体的腐蚀原因提出了合理的防腐蚀策略,希望能对埋地金属管道的防腐蚀的起到一定的帮助作用。     

基于改进BP神经网络优化的管道腐蚀速率预测模型研究

目的构造金属管道腐蚀速率预测模型,预测管道的使用寿命。方法分析了二氧化碳(CO2)和硫化氢(H2S)对金属管道的腐蚀过程,给出了管道腐蚀的化学反应方程式。引用了BP神经网络构造金属管道腐蚀速率的数学模型,采用了改进粒子群算法对预测模型进行优化。以45号金属管道为例,借助于Matlab软件对管道腐蚀速率进行仿真验证,并与实验测量数据进行对比和分析。结果金属管道腐蚀速率随着CO2或H2S压强的增大而逐渐增大,仿真结果显示CO2和H2S的最大腐蚀速率分别为7.20×10-5 mm/h和5.76×10-5mm/h,而实验测量结果显示CO2和H2S的最大腐蚀速率分别为7.14×10-5 mm/h和5.65×10-5 mm/h,采用改进BP神经网络预测模型所产生的相对误差在5%以内。结论金属管道在不同压强条件下,采用改进BP神经网络预测模型能够近似地预测其腐蚀速率,为金属管道的更换提供了参考依据。     

埋地金属管道腐蚀防护探讨

管道是油田地面生产中的最常用运输方式,主要承担油田石油、水、天然气等资源的运输工作,常见的管道材质分为两种,金属管道和非金属管道,其中金属管道的应用十分广泛,承担的油田大部分的运输工作。油田运输的介质往往存在较强的腐蚀性,和金属管道发生不同类型的物理化学反应,造成管道出现腐蚀穿孔等现象,给石油企业带来了巨大的经济损失,同时对周边的生态环境产生破坏。本文主要阐述了埋地金属管道腐蚀现状,以及影响金属管道腐蚀的主要因素,制定有效的防护措施。     

萨南油田管道距辅助阳极地床不同距离下的极化保护效果研究

外加电流阴极保护技术可以有效地抑制油田管道的腐蚀,已广泛应用于萨南油田各站厂内储罐底板及管道防腐工程,但对于站外系统埋地管道的应用与推广尚处于探索阶段。本文考虑站外埋地管道管径小、井网复杂、干扰因素多等特点,模拟外加电流阴极保护条件,试验了管道距辅助阳极地床不同距离下的极化保护效果,得出了萨南油田站外系统埋地金属管道实施外加电流区域性阴极保护技术,辅助阳极地床选址的基本原则,为同类管道保护起到了良好的指导作用。     

CTM遥测系统在阴极保护中的应用

通过应用CTM遥测系统,对实施外加电流阴极保护中转站或联合站的管道及容器等设备进行时时监测,并通过微机系统处理后得到可靠的工作参数,使实施深井阳极保护的中转站或联合站处于不间断保护状态,提高了阴极保护系统的运行效率和故障判断的准确率,从而有效地降低了埋地金属管道及容器的腐蚀速度,延长了管道及容器的使用寿命。     

对45#钢管道的缝隙腐蚀模拟研究

目的预测埋地金属管道缝隙表面电位分布和腐蚀速度。方法造金属管道缝隙腐蚀的几何模型,对腐蚀管道采取阴极保护,推导腐蚀管道的电化学反应动力方程式。对几何仿真模型的初始条件及边界条件进行约束,采用MATLAB软件对阴极保护电位分布规律和表面缝隙腐蚀速度的几何模型进行了仿真,并且与实验测量结果进行对比,得出了仿真结果与实验结果的相对误差。结果采用阴极保护金属管道表面缝隙腐蚀的底部仿真电位随时间的增加而反向增大,在极化时间50 h内最大电位为-8.6 V。采用阴极保护金属管道表面缝隙腐蚀的仿真电位随缝隙深度的增加而反向减小,在距离缝隙表面10 cm内最小值为-0.78 V。采用阴极保护金属管道表面缝隙的仿真腐蚀速度随时间的增加而逐渐减小,在前5年内腐蚀速度最小值达到0.334 mm/a。同时,电位分布和腐蚀速度的仿真值与实验测量值的相对误差在5%以内,误差较小。结论采用矩形缝隙模型可以近似预测阴极保护的电位分布和缝隙表面腐蚀速度,从而降低了金属管道腐蚀速度,避免了金属管道发生灾难性的事故。     

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。     

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.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

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.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

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.     

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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