钛制石化设备现场无损检测氢脆方法

为了确保钛制石化设备安全运行,应定期对其进行开镇检测,特别是像加氢反应器这样重要设备．钛制石化设备检测一般多考钢制压力容器检测内容进行,多偏重于检测各种类型的缺陷,如裂纹等．考虑到钛材因腐蚀吸氢或环境吸氢导致生成氨化物而未萌生裂纹,可通过一般检测（如着色探伤、X射线探伤）,但存在隐患,对设备安全运行十分不利．因而钛制石化设备安全运行评定时,需补充氢脆检测项目．钛设备吸氢程度的定量无损检测目前尚有困难．国外曾提出超声波、内耗或辐射同位素等方法,均未见实用化．根据多年来上海石化股份有限公司PTA装置加…     

钛材在焦化工业中的应用

金属钛强度高,具有优异的抗腐蚀性能,因而钛材在化工设备中正在获得广泛应用。焦化生产接触多种酸、碱及腐蚀性流体,设备腐蚀严重,设备选材是焦化工业中一项重要课题。本文以鞍钢化工总厂使用钛制熄焦塔除尘装置为例,论述钛材在焦化工业中的应用。     

钛铜共用的海水冷却器的牺牲阳极保护

钛在海水中具有优异的耐蚀性，而铜合金由于严重腐蚀则不能适应生产需要．用钛制作海水冷却器，能确保其安全稳定可靠运行，随着钛管制造工艺与焊接技术的进步，使得选用钛材制作海水冷却器变得更为容易．但由于钛材一次性投资相对较高，为了节省费用，在老设备改造时，只将省换为钛管，管板仍采用铜合金；或者管子与管板采用钛，而保留原铜合金复层的封头，但这样由于电偶接触会加速铜合金的腐蚀，仍须采用原有的电化学保护，而如果保护电位过负，即过度阴极极化，又会促使钛管口部位吸氢而致脆．上海石化公司1号乙烯装置的许多钛制海水冷…     

钛制化工设备的缝隙腐蚀

介绍了上海燎原化工厂等单位钛制化工设备发生缝隙腐蚀情况,分析了缝隙腐蚀产生的原因,提出了解决缝隙腐蚀的办法。     

钛腐蚀氢脆及其防止措施

概述了钛制化工设备发生腐蚀氢脆原因、条件，并对若干事例进行解析，提出了防止腐蚀氢脆的对策。     

纯钛温度计套管在含盐酸介质中表面变色原因分析

纯钛温度计套管在含盐酸介质中使用3个月后表面产生灰黑色现象。通过外观检查、化学成分分析、力学性能测试、微观组织形貌及EDS微区成分分析等方法，探究钛温度计套管表面变色原因。结果显示，钛温度计套管外表面局部呈灰色或灰黑色可能是因为发生了吸氢腐蚀；在盐酸环境下，介质中的F元素加速了钛基体吸氢腐蚀并使表面出现微裂纹。     

利用粉末冶金法生产高强度钛

日本大阪大学的接合科学研究所与美国睦军研究所共同研制成功兼有高强度与良好延展性的高强度钛。他们运用了粉末冶金法,将固溶了氧的纯钛制成金属粉末,随后烧结成形。所制得粉末冶金钛材,其强度和延伸率都高于传统熔炼钛材,由于生产过程中不进行熔炼。故生产成本低。这种高强度钛适用于医疗器械和化工设备等方面。     

低成本的不锈钢

普通不锈钢在一般环境中使用不容易生锈,但在接触到海水时,由于海水中氯离子的作用,不锈钢表层受到破坏而产生腐蚀。使用钛材虽然可以耐海水腐蚀,但钛材价格较贵。     

钛制硫酸铝蒸发器排管的腐蚀机理

通过极化曲线、腐蚀失重、热壁钛管试件和长钛管的电化学测试以及氢脆试验研究了钛制硫酸铝蒸发器排管的腐蚀破坏机理．结果表明钛的腐蚀是由于钝化膜破坏而造成的活性溶解和氢脆．钛在该体系中产生氢脆的临界电位为－２７０ｍＶ（相对于饱和甘汞电极）．ＸＰＳ分析结果证实了氢化钛的生成．     

钛管与管板焊接的保护措施

由于钛及其合金具有优异的性能,它们愈来愈广泛地应用于化工生产中。数年来本厂使用钛材制造了一千多台电解槽、蒸发器、冷却器、恒沸塔、分离器等高度耐腐蚀性的化工设备。然而实践表明,用钛材制设备,极关键的一环是掌握好钛材的焊接。目前     

钛合金表面清理技术分析

用机械法、化学法或机械与化学相结合的方法，对钛合金表面在加工过程中形成的氧化层进行了清理。清理的目的是使钛合 应用中表面不产生局部腐蚀，清理后钛合金表层不应产生大的应力和渗氢。对清理过的钛合金表面进行扫描电镜观察，清理效果达到了技术要求。     

钛离子注入改良铅和铅锑合金腐蚀行为的研究

应用钛离子注入增强铅和铅锑合金在5mol/LH2SO4中的抗腐蚀能力。腐蚀电流和铅的腐蚀量用于描述腐蚀行为。讨论了钛离子注入剂量对腐蚀行为的影响。铅在硫酸中的腐蚀包含两个过程:铅的氧化和氢气的析出。钛离子注入对两个过程有不同的作用。钛在铅和铅锑合金表面上的分布与钛的注入剂量有关。     

Experimental determination of the Critical hydrogen peroxide ion concentration for titanium alloys in alkaline hydrogen peroxide solution

The first assumption was that titanium and its alloy should have excellent corrosion resistance in alkaline hydrogen peroxide bleaching. However, the pulp mill experience of the corrosion resistance of titanium alloy conflict partly with the earlier knowledge. The corrosion of both titanium and titanium alloy was studied in alkaline hydrogen peroxide environment. The cell was equipped with a water circulation loop and chemistry monitoring system. The monitoring system adjusted the pH-value, hydrogen peroxide concentration and temperature of the solution. Both titanium and titanium alloy dissolved by uniform corrosion in passive state due to the hydrogen peroxide ion. This ion can destroy protective dioxide layer of titanium. The critical concentration of hydrogen peroxide ion could be estimated experimentally and for both titanium and titanium alloy it was 0.008 ± 0.008 M at 80 °C in alkaline hydrogen peroxide ion environment. However, theoretically based on thermodynamic no critical hydrogen peroxide concentration could be found whereas traces of this ion can attack titanium and titanium alloys. The experimentally determined corrosion rate of both titanium and titanium alloy seems to follow an exponential law as a function of hydrogen peroxide ion concentration, which could be explained by the Arrhenius equation.     

锆与钛耐蚀性比较及应用互补性

概述了锆与钛在各种环境下全面腐蚀与局部腐蚀性能比较,认为它们是互补的姐妹金属,是处理高温高压强腐蚀化工过程不可缺少的重要结构材料。对这两种材料在尿素、醋酸等化工环境中的应用作了比较分析。     

化工设备选用锆的基本考虑

化工设备设计只有在不锈钢与钛难以胜任时才考虑选用工业级锫.讨论了锆的耐蚀性与经济性,并分析了焊区晶间腐蚀、氢脆、点腐蚀与应力腐蚀破裂等及对应的防护方法.     

表面充氢对TA2在草酸溶液中腐蚀行为的影响

目的提高TA2在草酸溶液中的耐蚀性,揭示表面充氢提高钛在草酸溶液中耐腐蚀性能的机理。方法采用电化学充氢的方法对TA2试样进行表面充氢,采用SEM和XRD分析充氢对试样表面形貌和相组成的影响,并采用电化学测试和腐蚀浸泡实验研究不同充氢时间的TA2试样在草酸溶液中的耐蚀性。结果电化学充氢后,TA2试样表面会生成一层以Ti H1.5为主要组成相的氢化钛层,该氢化钛层的厚度随充氢时间的延长而增厚。电化学测试结果显示,随着充氢时间的延长,TA2试样在草酸溶液中的自腐蚀电位从–0.7 V(vs.SCE)逐渐增加到0 V左右,腐蚀倾向显著下降;极化电阻Rp则从0.2 kΩ·cm^2逐渐增加到了24.1 kΩ·cm^2,耐蚀性能增强。腐蚀浸泡实验结果表明,随着充氢时间的延长,TA2试样在草酸溶液中的腐蚀程度逐渐减弱,腐蚀速率也从未充氢时的4.63mm/a逐渐下降到0.03mm/a。结论在草酸溶液中,电化学充氢TA2试样表面生成的氢化钛层对Ti基体具有保护作用,并且保护效果随氢化钛层的增厚而增强。试样表面氢化钛层对Ti基体的保护作用除了与成分有关外,还与其结构相关,完整致密的氢化钛层可以对Ti基体起到很好的保护作用,而疏松多孔的氢化钛不仅不能保护Ti基体,反而还会促进Ti基体的腐蚀。     

钛在H2O2溶液中的腐蚀特性研究

通过分光光度计测定腐蚀后溶液中钛离子浓度的方法，研究了钛在H2O2溶液中的腐蚀特性，以及不同pH值条件下，K^＋，Ca^2＋，Na^＋，Mg^2＋，Cl^-，HPO4^2-，H2PO4^-等添加离子对钛腐蚀的影响。结果表明：Ca^2＋对钛腐蚀具有最强的抑制性，而HPO4^2-则具有最强的促进作用。分析认为：Ca^2＋通过吸附到钛表面形成CaTiO3或者CaO2来抑制钛的腐蚀：而HPO4^2-则是吸附到钛表面来增加表面氧化膜的缺陷，从而促进钛的腐蚀。     

Corrosion performance of titanium and titanium stabilised stainless steels

Abstract

Titanium and its alloys provide industry with a number of materials which are strong, light, and very corrosion resistant. In addition, titanium is added as an alloying constituent to some stainless steels to act as a stabiliser during welding. Over the past 30 years titanium alloys have been increasingly used in process industries, and wherever ‘nil corrosion’ is considered to be an essential design feature. The main drawback to titanium usage has been relatively high cost, but freedom from plant corrosion failures, reduced downtime for maintenance, and the increasing availability of titanium have made this metal and its alloys an attractive choice in recent years. Applications include process vessels, heat exchangers, marine fittings, offshore components, pump castings, and other applications where materials encounter a hostile service environment. Nevertheless, titanium and its alloys are still subject to some forms of corrosiveattack, such as galvanic corrosion, hydrogen absorption, erosion corrosion, and crevicecorrosion. Special welding procedures are also required, which, if ignored, can lead toserious problems. This paper outlines a number of recent investigations into some problems encountered in industrial and marine environments, where both titanium metal and titanium stabilised stainless steels have suffered unexpected corrosion attack. The case histories described illustrate that titanium may show unexpected corrosion problems if certain aspects of its corrosion behaviour are overlooked.     

Corrosion and Electrochemical Behavior of Titanium in aqueous sulfidic solutions

This paper summarizes the results of an investigation of the corrosion and electrochemical behavior, including cathodic hydrogen absorption, of titanium in acidic and alkaline sulfidic solutions. The effect of chloride and cyanide ions on the corrosion behaviour of titanium in sulfidic solutions was also studied. Titanium in acidic and alkaline sulfidic solutions exhibits a stable passive corrosion potential and negligible corrosion. Chloride and cyanide ions do not affect the corrosion behavior of titanium in sulfidic solutions. Cyanide ions under conditions of cathodic polarization tend to promote activation of titanium. Cathodic polarization at temperatures higher than 72 °C promotes hydrogen uptake in titanium and formation of titanium hydride. The rate of hydrogen uptake increases with decreasing pH and increasing temperature. Cyanide ions tend to promote the rate of hydrogen uptake, whereas chloride ions have essentially no effect.