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黄彥良 《腐蚀科学与防护技术》1993,5(3):229-229
<正> 本文对不锈钢于酸性氯离子溶液中的应力腐蚀开裂机理和应力腐蚀的缓蚀剂进行了研究。研究表明奥氏体不锈钢在酸性氯离子溶液中发生应力腐蚀开裂时处于活性阳极溶解状态,其应力腐蚀开裂机理既不能用钝化膜破裂-再钝化理论解释,同时也不能用氢脆理论解 相似文献
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奥氏体不锈钢是制造压水堆主回路部件的重要结构材料。奥氏体不锈钢在压水堆核电站中的服役整体表现优异,但服役过程中仍然发生过应力腐蚀开裂事故。发生冷变形是奥氏体不锈钢部件出现应力腐蚀开裂事故的主要原因,而切削加工及加工表面的后处理是在部件表面引入冷变形的主要工艺过程。本文基于过去20年本领域国内外相关研究结果,综述了切削加工等工艺在奥氏体不锈钢表面引入的塑性变形区的显微组织与残余应力特征,以及表面变形对奥氏体不锈钢在压水堆主回路高温水环境中的腐蚀及应力腐蚀裂纹萌生行为影响的研究进展。基于这些研究,指出了不锈钢应力腐蚀裂纹萌生研究中存在的问题、可能的解决办法,并对其他亟待开展的研究做了展望。 相似文献
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奥氏体不锈钢应力腐蚀和氢致开裂的机理 总被引:2,自引:0,他引:2
通过金相跟踪观察、力学测量及断口分析,研究了奥氏体不锈钢氢致开裂和应力腐蚀的机理.结果表明,无论是不稳定型(321)还是稳定型(310)奥氏体不锈钢,电解充氢时先产生塑性变形,当它发展到临界状态时就导致氢致裂纹的形核.但在42%MgCl_2沸腾溶液中应力腐蚀时,裂纹的形核和滞后塑性变形无关.两种(321)輿氏体不锈钢应力腐蚀的门槛值K_(ISCC)远比严重充氢时氢致开裂的门槛值K_(IH)要低.两者的断口形貌也不同,应力腐蚀是解理断口,且和K_I无关.而氢致开裂断口和K_I有关,K_I高是韧窝,K_I低则获得准解理断口.实验表明,氢在奥氏体不锈钢应力腐蚀(沸腾MgCl_2介质)过程中并不起主要作用. 相似文献
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铁素体-奥氏体双相不锈钢在H2S-Cl-H2O系统呵发生应力腐蚀开裂行为,为研究其开裂原因,用金相显微镜、电子探针、扫描电子显微镜等手段断裂试样进行分析。结果表明:在应力腐蚀开理解的过程中存在奥氏体相或铁素体相的选择性腐蚀;改变系统的PH值和Cl含量可使由铁素体和奥氏体构成的微电池的极性发生转变。 相似文献
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不锈钢应力腐蚀开裂综述 总被引:1,自引:0,他引:1
应力腐蚀开裂一直以来是不锈钢领域的重要研究课题,也是许多行业亟需解决的工程问题。应力腐蚀开裂是材料、环境和应力三者相互作用的结果,由于其复杂性,目前人们对不锈钢发生应力腐蚀开裂的机理尚存在许多不同的见解,但是经过近一个世纪的研究,从材料选择、环境控制等方面入手,预防不锈钢发生应力腐蚀是能够达到的。综述了应力腐蚀开裂的特征、机理和三个影响因素(应力、材料和环境)。对应力腐蚀的阳极溶解机理和氢致开裂机理进行了概述,阐述并探讨了不锈钢应力腐蚀开裂的滑移溶解机理、氧化膜开裂机理以及氢致开裂机理。归纳了组织结构对不锈钢应力腐蚀的影响,分析了材料成分如(Ni、Mo和N)的添加与应力腐蚀敏感性的关系,总结了环境因素在应力腐蚀中的作用,对特定介质中不锈钢的应力腐蚀规律进行了归纳,并探讨了温度变化对不锈钢应力腐蚀的影响。介绍了近年来关于控制不锈钢应力腐蚀开裂方法的研究进展,如晶界工程、细化晶粒以及涂层等。最后展望了不锈钢应力腐蚀开裂未来的研究方向。 相似文献
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双相不锈钢含有铁素体+奥氏体两相组织,具有良好的机械和腐蚀性能,尤其以出色的抗应力腐蚀开裂性能而著称。但双相不锈钢在特定的环境和拉应力共同作用下,会出现应力腐蚀开裂现象,由于应力腐蚀开裂通常难以被发现,从而导致灾难性的事故。在此基础上,从材质的成分和金相组织,温度、pH、氯离子和氧气浓度等工况环境,冷变形和残余应力等方面总结了影响双相不锈钢应力腐蚀开裂的因素。结合双相不锈钢的使用环境和应力特点,阐述了双相不锈钢的应力腐蚀开裂机理,包括电化学阳极溶解理论、氢脆机制、膜破裂理论、化学脆化一机械破裂两阶段理论、应力吸附破裂理论。依据应力腐蚀开裂机理,结合影响因素,通过合理添加合金元素开发出新的双相不锈钢、双相不锈钢等离子碳氮共渗或表面涂层、热处理工艺等方法,有效地降低双相不锈钢应力腐蚀开裂的敏感性。最后,从双相不锈钢应力腐蚀开裂机理和防护技术两方面展望了双相不锈钢应力腐蚀开裂未来的研究方向,从本质上减少应力腐蚀开裂事故的发生,保障生产的“安稳长满优”。 相似文献
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4 应力腐蚀开裂机理由于导致不锈钢材料发生应力腐蚀开裂的因素非常复杂,故解释不锈钢应力腐蚀开裂的理论很多,可谓众说纷云.但不管怎样,不锈钢的应力腐蚀开裂必然首先要发生选择性腐蚀,应力的主要作用在于对钝化膜的破坏及其再钝化的抑制,从而促进局部腐蚀.归纳起来,应力腐蚀开裂的机理可以分为三类:溶解机理;机械机理;混合机理.具体内容列于表2. 相似文献
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连多硫酸溶液中奥氏体不锈钢的应力腐蚀开裂 总被引:1,自引:0,他引:1
李志强 《腐蚀科学与防护技术》1995,7(1):58-65
评述了奥氏体不锈钢在连多硫酸溶液中的应力腐蚀开裂叙述环境、钢中碳含量、热处理、应力等因素的作用.讨论防止应力腐蚀计裂的措施 相似文献
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B. Prabha P. Sundaramoorthy S. Suresh S. Manimozhi B. Ravishankar 《Journal of Materials Engineering and Performance》2009,18(9):1294-1299
Stress corrosion cracking (SCC) is a common mode of failure encountered in boiler components especially in austenitic stainless
steel tubes at high temperature and in chloride-rich water environment. Recently, a new type of austenitic stainless steels
called Super304H stainless steel, containing 3% copper is being adopted for super critical boiler applications. The SCC behavior
of this Super 304H stainless steel has not been widely reported in the literature. Many researchers have studied the SCC behavior
of steels as per various standards. Among them, the ASTM standard G36 has been widely used for evaluation of SCC behavior
of stainless steels. In this present work, the SCC behavior of austenitic Fe-Cr-Mn-Cu-N stainless steel, subjected to chloride
environments at varying strain conditions as per ASTM standard G36 has been studied. The environments employed boiling solution
of 45 wt.% of MgCl2 at 155 °C, for various strain conditions. The study reveals that the crack width increases with increase in strain level
in Super 304H stainless steels. 相似文献
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Stress corrosion cracking of austenitic chromium-nickel stainless steels at ambient temperature For the chloride-induced SCC with transgranular crack path in austenitic 18Cr10Ni stainless steel, a critical temperature between 45 and 50°C exists. This critical temperature, however, is valid only for the passive state of the steel in nearly neutral, chloride-containing aqueous environments. In the active state, SCC with transgranular crack mode can occur at temperatures down to ambient temperature. The active state is caused by highly acidic, high-chloride containing aqueous corrosive media. Adherent aqueous films with these properties can grow on the surface of structural components inside swimming-pools when the water is disinfected by addition of chlorine. Under these conditions, failure of austenitic CrNi and CrNiMo stainless steels by SCC with transgranular crack path at ambient temperature is possible and actually occurred. SCC with preferentially intergranular crack path can also occur at ambient temperature when austenitic stainless steels with a sensitized microstructure are used. Under these conditions, the corrosion attack is caused by non-specific aggressive environments, e.g., adherent aqueous films not containing chloride ions. The crack mode, intergranular or mixed, depends on the stress level. 相似文献
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S. A. Lajevardi T. Shahrabi V. Baigi A. Shafiei M 《Protection of Metals and Physical Chemistry of Surfaces》2009,45(5):610-615
Despite the numerous researches in Stress Corrosion Cracking (SCC) risk of austenitic stainless steels in aqueous chloride
solution, no formulation or reliable method for prediction of time to failure as a result of SCC has yet been defined. In
this paper, the capability of artificial neural network for estimation of the time to failure for SCC of 304 stainless steel
in aqueous chloride solution together with sensitivity analysis has been expressed. The output results showed that artificial
neural network can predict the time to failure for about 74% of the variance of SCC experimental data. Furthermore, the sensitivity
analysis also demonstrated the effects of input parameters (Temperature, Applied stress and Cr concentration) on SCC of 304
stainless steel in aqueous chloride solutions. 相似文献
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Stress corrosion cracking (SCC) induced by chlorides frequently causes problems in applications where standard austenitic stainless steels are being used. Often this problem can be solved by the use of duplex stainless steels. In this report the mechanisms for SCC have been surveyed, and the cause for the high SCC resistance of duplex stainless steels has been discussed and evaluation of test methods for SCC and how duplex stainless steels respond to them, as well as practical experience of duplex stainless steels. The study shows that no single mechanism can be attributed to the good resistance to SCC of duplex stainless steels. Probably a synergistic effect of electrochemical and/or mechanical effects is responsible for the good performance. Test methods for SCC often give relatively good correspondence with real applications, but ranking is often doubtful, and comparisons of different material types should be made with caution. Numerous cases with SCC on standard austenitic stainless steels have been solved by the use of duplex stainless steels. 相似文献
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SCC crack growth mechanism of austenitic stainless steel X6 CrNiTi 18 10 in aqueous chloride solution at elevated temperatures The SCC crack growth mechanism of steam generator heat transfer tubes from stainless steel X6 CrNiTi 18 10 under internal stress conditions at elevated temperatures is discussed. Based on crack tip characterization by means of Scanning and Transmission Electron Microscopy and the evidence of hydrogen originated throughout the corrosion process a crack propagation model is presented. The results refer to a microcrack induced gradual crack growth caused by local hydrogen embrittlement. Microcrack growth has been observed due to slip-band decohesion. The crack growth rate is mainly influenced by the stress state near the crack tip and the hydrogen evolution throughout the corrosion process. 相似文献
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目的 对比研究原始、固溶和敏化态的304和321奥氏体不锈钢在模拟加氢催化氯化铵环境中的应力腐蚀(SCC)行为及机理。方法 将304和321奥氏体不锈钢经过热处理制备成固溶和敏化态试样,采用U形弯试样在模拟加氢催化氯化铵环境中浸泡的应力腐蚀试验方法对其进行研究,通过观察U形弯弧顶的腐蚀形貌和开裂时间,并结合腐蚀及裂纹的SEM照片和电化学测试结果进行分析。结果 原始和固溶状态304不锈钢U形弯试样在氯化铵溶液环境中开裂时间为25 d左右,断口形貌分别为穿晶断口和沿晶断口;敏化态试样18 d后发生开裂,断口形貌为穿晶和沿晶的混合断口。原始和固溶态321不锈钢U形弯试样在该环境中经过39 d均无应力腐蚀裂纹;敏化试样经30 d后产生宏观开裂。电化学测试结果显示,不同热处理态的304不锈钢在氯化铵溶液中均具有明显的点蚀敏感性,321不锈钢在该环境中耐点蚀和应力腐蚀的能力优于304不锈钢。结论 不同状态的304不锈钢在高温氯化铵环境中具有较强的应力腐蚀倾向,特别是敏化态试样;321不锈钢在该环境中的应力腐蚀敏感性相对较小,但敏化处理显著增加了其沿晶应力腐蚀倾向,而固溶态试样具有明显的沿晶腐蚀特征。 相似文献
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The efficiency of some organic additives for SCC inhibition of AISI 304 stainless steel in 1 M HCl solution can be demonstrated by the Slow Strain Rate (SSR) technique. 1 M HCl solution is the most aggressive solution for the SCC of AISI 304 stainless steel. The most suitable strain rate for studying SCC by the SSR method has been found to be 1 × 10−6s−1. Some organic additives have been tested as SCC inhibitors under the above conditions. Phenylthiourea (PTU), benzimidazole-2-thiol (BIT) and benzothiazole-2-thiol (BTT) have been found to inhibit SCC in stainless steel, thus confirming previous results obtained with a different technique. The inhibitive action of these substances can be attributed to their inhibiting effect on the anodic reaction of metal dissolution. 相似文献