盐水腐蚀及设备材质的选择

就盐水对碳钢、不锈钢、铜、钛及天然橡胶等材质的腐蚀情况作了简要介绍。提出了如何选择用于盐水生产设备的材质问题。     

冷冻盐水系统的腐蚀与防腐

从电化学角度分析了化工生产中冷冻盐水系统的腐蚀原因并提出了相应的防腐措施。     

浅谈氯离子对奥氏体不锈钢的腐蚀

结合工程实例,分析了氯离子对奥氏体不锈钢产生的几种腐蚀,并提出了相应的防腐措施。     

氯离子对18—8不锈钢点腐蚀的探讨

通过对１８－８不锈钢受氯离子点腐蚀的剖析,阐述了点腐蚀的危害,探讨降低和避免氯离子对１８－８不锈钢点腐蚀的方法及注意事项。     

碳钢和奥氏体不锈钢管道焊材选用研究分析

现如今,机械设备制造安装行业中碳钢和奥氏体不锈钢异种钢焊接日渐增多,虽可在不增加投资经费情况下大大提升安全系数,但异种钢焊接的不足也日渐突出,这主要与焊材选择不当有极大关联。为此,深入研究了异种钢焊接的材料选用,做到科学选材,保证焊接工作顺利正常开展。     

混合气脱水工序冷冻盐水阀门的应用

分析了氯乙烯合成工段混合气脱水工序-35℃冷冻盐水阀门的应用情况,介绍了四川省金路树脂有限公司所选用的截止阀工艺方案。     

用于浓碱液蒸发的旋转薄膜蒸发器

介绍了一种用于将烧碱溶液从ＮａＯＨ含量３０％（Ｗｔ）进一步浓缩蒸发的新型高效蒸发器。这种蒸发器具有很高的传热系数和蒸发强度，只需使用低压加热蒸汽（１３０℃左右）供热，大大减缓了碱液对设备的腐蚀，从而可用普通奥氏体不锈钢代替价值昂贵的镍材来制造浓效蒸发器。通过工厂使用实例的介绍和分析，说明这种蒸发器不但总传热系数很高，而且其热阻主要不是液膜或盐垢，而是来自导热系数较低的不锈钢材料。     

奥氏体不锈钢杀菌锅产生裂纹的原因与对策

对奥氏体不锈钢杀菌锅在运行中产生穿透性裂纹,从而导致泄漏失效的问题进行了全面分析。杀菌锅产生裂纹,既有运行方面的原因,也有材料本身和设备制造方面的原因。     

双效列管式蒸发器的制作及应用

明胶生产过程分为前处理和后处理。处理是化学反应过程,是明胶质量的关键;处理是物理变化过程,是明胶质量的保障段。在后处理工序,蒸发器又是整个过程的键设备。多年来,蒸发器一直困扰着明胶行的发展。前些年,国内大型明胶厂蒸发器均赖进口,现在则略有改观。进口蒸发器价格贵、维护费用高,小型明胶厂无力承受,     

应变和氯离子浓度对304不锈钢点蚀敏感性的影响

The effects of strain and chloride concentration on pitting susceptibility for type 304 stainless steel were studied in situ using the electrochemical technology under constant strain. The impact factor fc was brought forward to value the effect of strain on pitting. The pitting behaviors of type 304 stainless steel in various chloride concentrations under the strain levels 0%, 10%, and 30% were investigated. Potentiostatic polarization technology was used to study how the chloride concentration affected corrosion current density. The results indicated that fc increased substantially and pitting potential varied remarkably when chloride concentration was over 90 mg.L . Under the three levels of strain mentioned above, when chloride concentration was below 463 mg.L^-1,121 mg.L^-1, and 98 mg.L^-1 respectively, the pitting potential shifted towards positivity and, the passive film became more stable. When the strain was below 10%, the pitting susceptibility of type 304 stainless steel varied greatly as strain increased, whereas the susceptibility only changed a little when the strain was over 10%.     

2205双相不锈钢在醋酸环境下的点蚀行为研究

2205双相不锈钢由于其具有良好的力学性能,耐腐蚀性能被广泛地应用石油化工设备和管道用材料和选材设计中。本文主要利用电化学极化曲线及交流阻抗技术研究了22Cr双相不锈钢在醋酸以及氯离子条件下耐点蚀行为。结果表明,22Cr双相不锈钢在醋酸环境下有良好的耐腐蚀性能,由于氯离子的存在,增大了该材料的腐蚀倾向,同时也进一步加大了发生点蚀的几率。     

氯离子与冷却水系统中不锈钢的腐蚀

综述了有关氯离子对冷却水系统中不锈钢腐蚀研究的最新进展,涉及冷却水中氯离子引发不锈钢孔蚀、缝隙腐蚀和应力腐蚀开裂的机理,氯离子的限度,以及影响水中不锈钢腐蚀的其他因素.对如何应对冷却水中氯离子的负面效应提出了见解.     

Passivity and passivity breakdown of 304 stainless steel in alkaline sodium sulphate solutions

The passivity and passivity breakdown of 304 stainless steel were investigated in 0.25 M Na₂SO₄solutions of pH 10. The effect of applied potential and the presence of Cl^– ions in the electrolyte were also studied. Different electrochemical methods such as open circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS) were used. The results showed that the steel electrode passivates under open circuit conditions and also under potentiostatic control. The rate of passive film thickening under open circuit conditions follows a simple logarithmic law. Addition of Cl^– ion shifts the polarization curves in the active direction and above a critical chloride concentration, [Cl^– ] 0.15 M, pitting corrosion occurs and the pitting potential, E _pit, decreases linearly with the logarithm of [Cl^–]. The addition of sulphate ions to the chloride-containing solutions was found to inhibit the pitting process, and at [SO^2- ₄] 0.25 M, a complete immunity to pitting corrosion was recorded. The impedance measurements provided support for film thickening and film breakdown reactions. An equivalent circuit model which consists of a pure resistor, R , in series with a parallel combination of a pure resistor, R _p, and a constant phase element, Q, was proposed to describe the electrode/electrolyte interface. The passive film thickness was found to increase with applied potential up to a critical value of 0.3 V. At higher voltages, breakdown of the passive film occured.     

Electrochemical investigations of pitting corrosion behaviour of type UNS S31603 stainless steel in thiosulfate-chloride environment

The pitting corrosion behaviour of type UNS S31603 stainless steel (316L SS) in 0.01, 0.05 and 0.1 M thiosulfate ion (S₂O₃ ^2–) in the absence and presence of various concentrations of chloride ion (Cl^–) was studied using the cyclic potentiodynamic polarization method. The influence of major factors which affect pitting corrosion such as pH and temperature, were also investigated. It was found that both the pitting potential (E _pit) and the repassivation potential (E _rp) decreased with increase in Cl^– concentration and solution temperature and a more pronounced difference in E _pit values for various concentrations of S₂O₃ ^2– in 1.0 M Cl^– was obtained at lower temperatures. The effect of pH on E _pit, E _corr and E _rp values for different concentrations of S₂O₃ ^2– in the presence of 1.0 M Cl^– was also determined.     

锅炉不锈钢管的应力腐蚀探究

本文讨论了常见不锈钢发生应力腐蚀的介质环境及应力腐蚀机理,然后探究了Cl-浓度、拉应力、溶液温度、溶解氧、pH等因素对腐蚀的影响,并介绍了几种常用的应力腐蚀试验方法和防治措施,对计算机模拟软件在电厂的应用提出了展望。     

乙二醇不锈钢蒸发器晶间应力腐蚀的试验研究

采用一种新型的试样加载方式模拟乙二醇蒸发器不锈钢材料焊接接头附近的应力,通过硫酸-硫酸铜腐蚀实验和金相分析对1Cr18Ni9Ti和SAF2205 2种不锈钢材料在应力状态下,焊态与敏化状态试样进行晶间腐蚀敏感性评价,实验结果表明:在相同的焊接工艺条件下,随着腐蚀时间的增长, 1Cr18Ni9Ti焊态试样的抗晶间应力腐蚀能力有所下降;而敏化态的试样抗晶间应力腐蚀能力有明显降低。对于SAF2205双相不锈钢,无论在焊态下还是在敏化态下,均表现出良好的抗晶间应力腐蚀性能。综合而言,SAF2205的耐晶间应力腐蚀能力要比1Cr18Ni9Ti强。     

Corrosion of stainless steels covered by exopolymers

After a biologically induced corrosion in a 304 stainless steel tube electrochemical tests were carried out on the affected areas to characterise the nature of attack of the steel covered by the excreted exopolymers. Once the corrosive attack has been developed, the samples were removed from the solution, dried out for 1 month and re-immersed in the same well water which caused the attack. Polarization curves and impedance measurements made on non attacked welds, reference stainless steel and the metal covered by the exopolymer confirm that a reactivation of the corrosion process in previously damaged welded areas is produced. However, the corrosive attack has not been so severe than the initially produced by bacteria and after 28 days of immersion the progress of the attack is probably due to the previous activation of the steel surface rather than the microbiological activity.     

Electrochemical pitting behaviour of type 321 stainless steel in sulfide-containing chloride solutions

The pitting behaviour of type 321 stainless steel in sulfide-containing chloride aqueous environments was studied using cyclic potentiodynamic polarization. A well-established correlation between H₂S and Na₂S₂O₃ in the study of corrosion was applied, that is, H₂S was simulated by Na₂S₂O₃. The major factors affecting the pitting corrosion of type 321 stainless steel are the Cl^- concentration, solution pH and temperature. The results clearly indicate that both E_pit and E _pp decrease with increasing Cl^- concentration and temperature, while I _pass is more sensitive to temperature variation. E _pit decreased with decreasing pH in the range 2 < pH < 7.5. The surface morphology and chemistry of the corroded type 321 stainless steel resulting from anodic polarization in 0.01 M S₂O ₃ ^2- -containing Cl^- solution were analysed by XRD, SEM and EPMA. A higher concentration of sulfur was found in the pits, and the dark surface film was mainly composed of FeS and -Fe₂O₃. The results describe the pitting behaviour of type 321 stainless steel in sulfide-containing Cl^- aqueous environments.