凉水塔钢结构防腐蚀涂层失效原因分析及改进

该文详细阐述了石油化工系统循环水凉水塔钢结构由于金属表面处理和采用不当的防腐蚀材料,造成防腐层过早的损坏,使钢结构腐蚀严重。通过对防腐蚀涂层及金属腐蚀原因的分析,采用聚酰胺防腐蚀材料对金属结构的防腐蚀,通过2年多使用效果很好。     

油田埋地管线腐蚀现状及防腐蚀技术探讨

油田埋地管线在油田生产中发挥重要作用,为提升管线防腐蚀效果,对造成埋地管线外防腐蚀层和管体腐蚀的原因进行了分析,从管线选材、设计施工、优化生产工艺及加强防腐蚀管理等方面提出了相应的防腐蚀措施。     

氨法烟气脱硫装置腐蚀与防护

针对某热电厂氨法烟气脱硫装置防腐蚀设计以及运行中的腐蚀现状,分析了该装置的腐蚀原因。结果表明,脱硫浆液中硫酸根离子、氯离子等对金属设备的酸腐蚀、颗粒物结晶腐蚀和机械冲刷磨损,以及脱硫后低温湿烟气凝结成低浓度酸液对烟囱等设备的露点腐蚀是造成装置腐蚀的主要原因。提出了氨法脱硫装置防腐蚀对策,主要包括合理选用防腐蚀设备材料;严格按照防腐蚀施工工艺标准,确保防腐蚀施工质量;运行中严格控制引起腐蚀的因素,降低设备腐蚀速率。     

复合涂层在立井井筒装备中的应用

根据立井装备环境条件及腐蚀原因,采用单一防腐蚀方式不能满足立井井简装备防腐蚀需要。通过对电弧喷涂防腐蚀机理分析,将电弧喷锌和涂防锈漆复合防腐蚀工艺应用于立井井筒装备中,即电弧喷锌作为防腐蚀层,采用环氧富锌漆对喷锌层进行封闭,防腐蚀效果良好。     

一例钢结构防腐蚀涂料施工事故分析

从钢结构防腐蚀涂层的设计、选材、施工技术等几方面分析了山西某焦化厂脱硫缶外壁防腐蚀涂料施工中出现问题的原因,据此提出防腐蚀工程管理的具体内容。     

隧道穿越段管道防腐蚀层检测技术与实践

盾构隧道是石油天然气管道穿越大型河流的重要通道,其典型的施工方式和运行工况给管道防腐蚀带来了特殊要求。为了了解盾构隧道内管道防腐蚀的应用现状,通过对国内几条有代表性的长输管道盾构隧道进行直接检测,对比分析了水封隧道和干隧道两种不同环境形式中管道防腐蚀层存在的问题及管体存在的腐蚀状况,分析了防腐蚀层失效的原因和不同表现形式,提出了盾构隧道内管道防腐蚀的技术改进措施。     

氨法脱硫装置中的防腐蚀形式技术探讨

本文介绍了氨法脱硫装置(FGD)中的腐蚀特点,以及针对性地对最常见的防腐蚀形式(VEGF鳞片材料和整体玻璃钢设备)的关键技术进行了分别探讨和研究,重点分析了鳞片材料在氨法脱硫装置中的失效原因和可能,并据此重点地提出防腐蚀技术建议(包括防腐蚀结构和方式)。     

复合涂层在立井井简装备中的应用

根据立井装备环境条件及腐蚀原因，采用单一防腐蚀方式不能满足立井井简装备防腐蚀需要。通过对电弧喷涂防腐蚀机理分析，将电弧喷锌和涂防锈漆复合防腐蚀工艺应用于立井井筒装备中，即电弧喷锌作为防腐蚀层，采用环氧富锌漆对喷锌层进行封闭，防腐蚀效果良好。     

工业污废水池防腐蚀工艺及防腐蚀失效探讨

本文就常见的工业污废水处理池中的防腐蚀工艺进行了总结,包括对材料的选择和施工工艺,同时也对各类常见防腐蚀失效的原因从材料选型及工艺选择、基体要求等方面进行分析与总结。     

核电站工程阶段的腐蚀问题及管理建议

结合工程案例,研究了核电站工程阶段常见的腐蚀问题,并分析问题产生的原因。结果表明,在核电站工程阶段应对设备进行科学的防腐蚀分级,并在设计、制造、存储和安装进行防腐蚀管理。     

阿那其根醇提取物对两种炎症模型作用机制研究

目的: 研究阿那其根醇提取物(EERAP)对二甲苯致小鼠炎症模型和脂多糖(LPS)诱导RAW264.7细胞炎症模型的影响。方法: 将50只小鼠,随机分为对照组(饮用水)、EERAP高剂量组(640 mg/kg)、中剂量组(320 mg/kg)、低剂量组(160 mg/kg)和阿司匹林组(120 mg/kg),采用二甲苯建立小鼠炎症模型,比较小鼠耳廓肿胀度及耳廓毛细血管通透性的变化,ELISA法测定各组炎症渗出液丙二醛(MDA)、超氧化歧化酶（SOD）的含量;LPS诱导RAW264.7细胞建立细胞炎症模型,ELISA法测定核转录因子kappa B（NF-κB）和肿瘤坏死因子-α（TNF-α）含量。 结果: 在二甲苯致小鼠炎症模型中,EERAP高、中、低剂量组均能抑制小鼠耳廓肿胀度,减少小鼠耳廓毛细血管通透性,减少渗出率,与空白对照组比较均有统计学差异(P<0.01);EERAP高、中、低剂量组均能降低血清中MDA含量（P<0.05）,显著升高SOD含量(P<0.01);在LPS诱导的RAW264.7细胞炎症模型中,EERAP在3.125～200 μg/mL范围内可降低TNF-α含量,而在2 μg/mL时也可以降低细胞NF-κB含(P<0.05),与阿司匹林组无统计学差异。结论: EERAP可能是通过抑制MDA、TNF-α和NF-κB的生成,升高SOD的水平,起到抗炎、抗氧化作用。     

Mechanism of improvement of formability in pulsating hydroforming of tubes

The mechanism of improvement of formability by the oscillation of internal pressure in a pulsating hydroforming process of tubes was examined. Free bulging hydroforming experiments of mild steel tubes under oscillating and constant inner pressures were performed. For a high constant pressure, a round bulge with local thinning was observed, whereas wrinkling occurred for a low constant pressure. The occurrence of these defects was prevented by oscillating the internal pressure in the pulsating hydroforming. In the pulsating hydroforming, a uniform expansion in the bulging region was obtained, and thus the formability was improved by preventing the local thinning. It was found from an observation of deformation behaviour, using a video camera, that the tube is uniformly expanded by repeating the appearance and disappearance of small wrinkling. The cause of the uniform expansion for the pulsating hydroforming was also interpreted from the variation of stress components. In addition, a similar deference in deformation behaviour between the oscillating and constant inner pressures was also obtained in finite element simulation.     

钛铁矿烧结性能研究

将钛铁矿在氩气及空气气氛中不同温度下进行烧结。采用XRD及热分析研究了钛铁矿在不同温度下烧结后的相组成及质量变化。结果表明,在氩气气氛950℃下烧结后,钛铁矿的物相组成没有发生变化;在空气中不同温度烧结后,600～800℃较低温度区间,钛铁矿转变为热力学亚稳定的Fe2Ti3O9,950℃以上烧结时,钛铁矿转化为热力学稳定的Fe2TiO5。钛铁矿的晶体结构由烧结前的三方结构经低温烧结后转变为亚稳态六方晶系的Fe2Ti3O9,950℃以上烧结后,晶体结构转变为斜方晶系的Fe2TiO5。     

Development of the technology of ultrasonic welding of components made of Capron tapes

The technology of ultrasonic welding of components made of Capron tapes producing welded joints with high strength parameters has been developed. The numerical values of the main parameters of the conditions of ultrasonic welding of the Capron tapes are determined. It is shown that the increase in the amplitude and welding pressure shortens the welding time. The experimental results show that the Capron tapes are characterized by geometrical homogeneity in both the transverse and longitudinal direction so that the welded joints can be produced both along and across the tape.     

Calculation of the parameters of pulsed laser welding of thin sheets of aluminium alloys

One of the main advantages of the MIG/MAG process is its high productivity. In most of the applications, positive polarity is used, due to its greater arc stability, generation of less splatter and formation of weld beads with suitable geometry. However, in some applications, there is a need for greater production capacity than that offered by conventional MIG/MAG welding. In the literature, it is stated that negative polarity provides a higher fusion rate than positive, despite leading to a high level of splatter and unsuitable formation of the weld bead. Unfortunately, there is not much information available on the effects of the process variables in this polarity, much less justification for such. Therefore, this work is an attempt to try to understand the reason why there is a higher deposit rate in negative polarity, as well as the related effect on the geometry of the weld beads. To do this, comparative MIG/MAG welds were produced in both positive and negative polarities, using two compositions of shielding gases at two current values. The transfer mode and the behaviour of the arc were analysed by synchronized profiling. The geometric profile of the weld bead was evaluated by means of metallographic procedures. From the results, which disagree in part with the current literature, it was seen that both the transfer mode as well as the morphology and the appearance of the weld bead are dependent on the composition of the shielding gas. To explain the phenomena inherent in the greater fusion rate of wire in DC ? , the suggestion is that the fact that arc scales the sides of the wire in this polarity may be the governing factor.     

Mechanism of electro-generating leaching of chalcopyrite-MnO_2 in presence of Acidithiobacillus thiooxidans

A dual cell system with chalcopyrite anode and MnO_2 cathode was used to study the relations between time and such data as the electric quantity and the dissolution rates of the two minerals in the electro-generating leaching(EGL)and the bio-electro-generating leaching(BEGL),respectively.The results showed that the dissolution rates for Cu~(2+)and Fe~(2+)in BEGL were almost 2 times faster than those in EGL,and nearly 3 times for Mn~(2+);the electric output increased nearly by 3 times.The oxidation residu...     

BGA焊接技术的探讨

随着1C技术的不断进步,IC正在向着集成化、小型化、高性能、多管脚的方向发展,BGA封装形式在IC技术的发展中得到了广泛地应用,因此BGA封装的焊接技术越来越受到重视.本文主要根据BGA封装在回流焊接中出现的短路、虚焊、空洞、溅锡等现象,分别从PCB焊盘设计、器件保护、钎料选择及回流焊温度曲线的确定等方面进行了分析,并...     

The assessment of the value of GPR imaging of flexible pavements

A survey of the different applications of ground penetrating radar (GPR) for highway pavement investigation is presented with a critical appraisal of the success with which it was applied. The problems associated with this technique are also discussed. These include discussions of the accuracy of the technique and the difficulties in trying to interpret the recorded signals. Suggestions for the future direction of the research in this field to enhance the data collection and interpretation are made. The remainder of this paper investigates the advances that can be made in the use of existing GPR technology in the field of thin pavements investigation.     

Inhibition of copper corrosion by coatings of alkyl esters of carboxybenzotriazole

The inhibitive effect of coatings formed dipping copper in solutions of alkyl esters (methyl, butyl, hexyl and octyl) of carboxybenzotriazole was studied by potentiodynamic polarisation, electrical impedance spectroscopy, coulometry and surface enhanced Raman scattering (SERS) spectroscopy. The inhibition efficiency of the dry film depends on type of solvent used in the coating solution, temperature and period of immersion. Pretreatment by immersing copper in hot (70 °C) aqueous solution (1×10⁻⁴ M) for approximately 2-3 h gave a film with the highest degree of corrosion protection. Higher temperatures or longer time of immersion reduce the protectiveness of the film. Copper coated using either alcohol or acetone as solvent was less well protected than when dipped in aqueous solution. Impedance spectra showed that the film formed by pretreatment in aqueous solution of inhibitors can be stable in acidic sulphate corrodent (pH∼0) for up to 3 days before breaking down. In near-neutral sulphate solution (pH∼8) the film can be stable for up to 10 days. In both acidic and neutral sulphate solution, the inhibition efficiencies of the protective film increased with the length of the alkyl ester chain in the order: methyl < butyl < hexyl < octyl. This is different to the behaviour of copper in a near-neutral aqueous corrodent containing dissolved inhibitor. The ester films also exhibit anti-tarnishing properties in a sulphidising environment with inhibition efficiencies increasing as the alkyl chain is made longer. Again the films formed by pretreatment in aqueous solution have superior anti-corrosion properties compared to those formed by pretreatment in either alcohol or acetone solution. SERS measurements indicate that the azole ring is close to the copper surface with chemisorption through azole nitrogen. It is also suggested that the hydrocarbon chain of the ester is physically adsorbed on the copper.     

ULCB钢焊接熔池凝固过程数值模拟

采用元胞自动机法建立ULCB钢焊接熔池凝固过程的宏微观耦合模型,模拟非均匀温度场下焊接熔池凝固过程的组织形貌演变和溶质场分布,分析不同形核参数和合金成分对焊接熔池枝晶形貌的影响。结果表明,熔池边缘形成柱状晶,熔池中心形成等轴晶,柱状晶和等轴晶相互抑制长大;枝晶生长过程中始终存在着枝晶偏析现象;形核密度和合金成分影响枝晶的形核和生长,随着形核密度和合金成分的增加,焊缝中等轴晶区域增加,晶粒细化。