H2S应力腐蚀环境下的压力容器用钢的选用探讨

本文通过对湿Ｈ２Ｓ应力腐蚀环境下，Ｈ２Ｓ应力腐蚀的机理及其影响Ｈ２Ｓ２腐蚀的因素的分析，结合工程实践，提出了在不同的Ｈ２Ｓ分压下的压力容器用钢的选材要求，以供工程设计中参考。     

在役压力容器H2S应力腐蚀的检验

本文系统介绍了压力容器应力腐主机理和失效方式，并列出了能和Ｈ２Ｓ产生应力腐蚀的和各阁下好在在役压力容器的检验中如何发现应力裂纹和可能产生应力腐蚀的部位。     

碳钢空冷器硫化过程预防应力腐蚀开裂措施

催化剂预硫化是多数加氢装置必经的过程,由于硫化过程使系统中硫化氢的浓度会达到上万ppm,碳钢空冷器发生湿硫化氢环境应力腐蚀开裂的概率大大提高。本文就近期两个新开工炼厂为例,一个发生湿硫化氢环境下应力腐蚀开裂事故,一个安全渡过硫化阶段,从不同硫化过程到碳钢空冷器制造过程进行对比阐述。分析如何避免碳钢材质空冷器发生湿硫化氢环境下应力腐蚀开裂问题。     

H_2S应力腐蚀在石化装置的危害

加工含硫原油的炼油厂,设备及管线会出现H2S应力腐蚀,此种腐蚀对在石化装置的危害十分大,根据多年的现场经验,总结H2S应力腐蚀的出现及处理方法。     

湿硫化氢环境中的硫化物应力开裂腐蚀分析

阐述了炼油装置湿硫化氢环境中硫化物应力开裂（ SSC）腐蚀的环境条件、腐蚀机理、腐蚀因素以及腐蚀危害程度和敏感性的判定方法,并提出如何选材和采取措施来降低湿硫化氢环境中SSC腐蚀风险。     

不同硫化物浓度碱性溶液中16Mn钢及热影响区应力腐蚀行为

利用U形弯试样浸泡实验和电化学技术研究了16Mn钢及其模拟热影响区在不同硫化物浓度的碱性(pH=11.7)介质中的应力腐蚀开裂(SCC)行为与机理。结果表明:16Mn钢原始组织、粗晶组织(空冷组织)和硬化组织(淬火组织)在碱性硫化物环境中均能形成保护性腐蚀产物膜、导致电极过程近似呈钝化状态,钝化电流密度依次降低;淬火组织析氢电流密度较高,腐蚀速度较低,长期服役后会造成靠近熔合线部分腐蚀深度大而暴露出残余拉应力区,引起SCC;HAZ中硬化组织、粗晶组织和原始组织在碱性硫化物环境下SCC敏感性逐渐降低,硬化组织具有较明显的SCC敏感性,粗晶组织和原始组织SCC敏感性小;硫化物浓度升高,16Mn钢及其模拟热影响区SCC敏感性增加;16Mn钢焊缝区在碱性硫化物环境中SCC裂纹扩展机制为阳极溶解机制。     

高浓度H2S环境下的腐蚀与防腐

分析了干湿Ｈ２Ｓ环境的腐蚀机理与特点,从设备选材、设计制造及使用等方面对减轻Ｈ２Ｓ腐蚀进行了讨论。     

石化厂湿硫化氢环境下钢的腐蚀开裂与选材

叙述了石化厂湿硫化氢环境下钢的腐蚀类型、应力腐蚀及氢致开裂的机理、影响因素、危害程度的评定以及防护对策。     

压力容器在设计制造过程中如何防止或避免应力腐蚀开裂

通过对应力腐蚀的特点及影响因素、裂纹形态的分析,提出避免应力腐蚀开裂的防控措施,为压力容器设计人员和制造单位提供参考。     

16MnR钢在含H2S介质中慢拉伸应力腐蚀试验研究

通过慢拉伸应力腐蚀试验 ,研究了 1 6MnR钢在含H2 S介质中的应力腐蚀行为 ,采用均匀设计方法分析了H2 S含量、Cl- 含量、温度和pH值等参量对 1 6MnR钢应力腐蚀敏感指数的影响 ,并对试件微观断口形貌进行了扫描电镜分析     

Pitting and stress corrosion cracking behavior in welded austenitic stainless steel

The effect of microstructural changes in 304 austenitic stainless steel induced by the processes of gas tungsten arc welding (GTAW) and laser-beam welding (LBW) on the pitting and stress corrosion cracking (SCC) behaviors was investigated. According to the in situ observations with scanning reference electrode technique (SRET) and the breakdown potentials of the test material with various microstructures, the GTAW process made the weld metal (WM) and heat-affected zone (HAZ) more sensitive to pitting corrosion than base metal (BM), but the LBW process improved the pitting resistance of the WM. In the initiation stage of SCC, the cracks in the BM and HAZ propagated in a transgranular mode. Then, the crack growth mechanism changed gradually into a mixed transgranular + intergranular mode. The cracks in the WM were likely to propagate along the dendritic boundaries. The crack initiation rate, crack initiation lifetime and crack propagation rate indicated that the high-to-low order of SCC resistance is almost the same as that for pitting resistance. High heat-input (and low cooling rate) was likely to induce the segregation of alloying elements and formation of Cr-depleted zones, resulting in the degradation in the corrosion resistance.     

再生器发生应力腐蚀开裂的探讨

针对炼油厂催化装置再生器下部件壁发生开裂的现象，通过分析催化装置近几年原料油田的变化、烟气露点测试结果与现场器壁温度对比，认为这是一种氢应力腐蚀开裂（SCC）。结合氢应力腐蚀特点制定了修复方案，特别是焊前预热、焊后热处理，选择合适的焊条及板材，降低了焊道和热影响区硬度，消除残余应力。并对再生器下部壁采取保温措施，确保再生器下部外壁温高于露点（137℃），使之无法在下部器壁形成水汽冷凝液，有效防止SCC的发生。     

应力腐蚀破裂与化学清洗

简述化学清洗是防止化工设备应力腐蚀破裂的重要措施但必须指出,若化学清洗处理不当,也有可能会造成应力腐蚀破裂的危险     

Fundamentals of hydrogen evolution reaction and its implications on near-neutral pH stress corrosion cracking of pipelines

In this work, electrochemical techniques were utilized to investigate the hydrogen evolution reaction on X-70 pipe steel and the hydrogen permeation through the steel in near-neutral pH environmental condition. The results demonstrate that the steel has always been in an active-dissolution state in near-neutral pH solution and there is no film formed on the steel surface. Hydrogen evolution is inhibited by anodic polarization of the steel, which is attributed to the alternation of hydrogen evolution mechanism and kinetics on the anodially polarized steel. Combined with slow strain rate tensile tests, it is found that the high susceptibility of steel to stress corrosion cracking (SCC) is always associated with a high hydrogen permeation current. A thermodynamic model was developed, by analyzing the change in free-energy of the steel in the presence and absence of hydrogen and stress, to determine the interactions of hydrogen, stress and anodic dissolution at the crack-tip. The role of hydrogen involvement in pipeline near-neutral pH SCC could be determined quantitatively by characterizing the effect of hydrogen concentration on the dissolution rate of steel and the synergism of hydrogen and stress to promote crack growth.     

Phase angle analysis for stress corrosion cracking of carbon steel in fuel-grade ethanol: Experiments and simulation

The stress corrosion cracking (SCC) of carbon steel in simulated fuel-grade ethanol (SFGE) was investigated using electrochemical impedance spectroscopy (EIS) and slow strain rate test (SSRT). Phase angle at low frequency range (<1 Hz) is sensitive to SCC process of carbon steel in SFGE. Phase angle decreases during an active crack growth. Frequency at maximum phase angle also increases towards an active cracking region at around 1 Hz. A transmission line model (TLM) is used to simulate the EIS response for SCC based on real geometrical parameters. By systematically changing the values of the circuit elements, the activities of the sample surface, crack tip and crack wall were studied in detail. By comparing the Bode plots from both experiment and simulation during SCC, a detailed mechanistic picture is derived to describe the behavior of the stress corrosion crack on carbon steel in the fuel-grade ethanolic environment.     

裂解装置EH-1238换热器腐蚀原因分析

介绍了大庆石化公司化工一厂裂解装置工艺水汽提塔进料加热器腐蚀情况,通过对壳程工艺介质的分析和管束的宏观检测,对管束腐蚀机理进行分析,得出结论.     

硫化钠对镀锌钢表面铈盐转化膜耐蚀性的影响

采用硝酸亚铈、六偏磷酸钠组成的转化液,在镀锌钢表面制备了铈盐转化膜,研究了硫化钠(Na2S)对其耐蚀改性作用。通过中性盐雾(NSS)试验考察了Na2S质量浓度、pH、温度、时间等工艺条件对转化膜耐蚀性的影响,通过单因素试验得到最佳转化条件为：Na2S 6 g/L,温度25°C,pH 0.8,转化时间3 min。用扫描电镜和能谱分析了有无Na2S改性的铈盐转化膜的形貌结构及成分,用Tafel极化曲线法比较了它们的耐蚀性。结果表明,加入Na2S增强了铈盐转化膜与镀锌钢基体的附着力,提高了O、P、Ce等主要耐蚀成分的含量,耐盐雾腐蚀时间由改性前的24 h延长到改性后的96 h,耐蚀性显著提高。     

酸性NaCl溶液中304控氮不锈钢腐蚀过程的声发射特征

采用声发射技术和电化学噪声技术研究了304控氮不锈钢C型环试样在0.5mol·L-1NaCl与1.5mol.L-1H2SO4的混合溶液中,恒载荷情况下的腐蚀过程。分析了腐蚀过程中所产生的声发射信号的振铃数随时间分布情况,以及不同阶段的声发射信号的频谱特征。同时对比分析了声发射检测结果与电化学噪声检测结果。结果表明,声发射检测技术对于304控氮不锈钢在酸性NaCl溶液中所产生的腐蚀声发射信号很敏感,在不同腐蚀阶段中,声发射信号特征差异明显,对于判断不同腐蚀阶段具有指导意义;声发射与电化学噪声测试结果基本一致,将声发射检测与电化学噪声检测结合使用,有助于使现场检测结果更加可靠。     

化工设备中应力腐蚀的机理及防护

本文分析了压力容器机器设备在氯化物、硫化物、浓热碱、高温高压水溶液介质中应力腐蚀开裂的机理,并简要的介绍了针对不同情况,所采取的防护措施。