不锈钢板焊接件的腐蚀特性研究

本文利用金相、扫描电镜对不锈钢薄板热交换器产生的腐蚀形貌进行了显微组织观察、分析,用能谱仪对其白色带状物和表面附着物进行了成分测定。结果表明:白色带状物是析出的碳化铬(Cr_(23)C_6),它使周围贫铬区被腐蚀。表面附着物是硫化物,它是引起孔蚀的重要因素,导致失效的原因还有应力腐蚀和缝隙腐蚀。     

304不锈钢焊管应力腐蚀开裂原因

某公司不锈钢焊管使用过程中出现大面积开裂泄露。采用宏观检验、化学成分分析、金相检验、SEM、EDS能谱分析等方法,对该管道的开裂泄露进行失效分析。结果表明,该焊管的开裂主要为氯离子应力腐蚀开裂。焊管成型后未热处理造成的残余应力、管外面橡塑保温材料释放出的氯离子共同造成了该不锈钢焊管的应力腐蚀开裂。     

异材焊接件A508/52M/316L在高温水环境中的应力腐蚀破裂

采用慢应变速率实验(SSRT)方法,研究了先进的异材焊接件A508/52M/316L在模拟H压水堆一回路290℃高温水环境中的应力腐蚀破裂(SCC)特性.实验在-780 mV至+200 mV范围的电位下进行,模拟一回路水化学从低O含H的理想低电位状态到溶解O2明显超标的高电位状态的服役环境.该焊接件显微组织和化学成分分...     

氯化物溶液中敏化304不锈钢应力腐蚀开裂的临界电位

研究了氯化物浓度、溶液温度、应力及敏化程度对敏化304不锈钢在NaCI水溶液中晶间型应力腐蚀开裂的影响。结果表明，材料的敏化程度、NaCI浓度、溶液温度和应力对敏化304不锈钢的ER.SCC有显著的影响，敏化304不锈钢的DR．SCC低于ER．CREV，应力腐蚀开裂发生在正于ER．SCC的电位范围，而电位低于该值则免于发生应力腐蚀开裂，由此得知，ER．SCC可适用于评价敏化不锈钢的应力腐蚀开裂敏感性。     

奥氏体不锈钢炉体应力腐蚀破裂失效分析

３１６Ｌ不锈钢是一种耐蚀性能很好的材料,但是安装质量特别是焊接质量对其应力腐蚀破裂（ＳＣＣ）性能很有很大的影响,本文针对某厂多次沿焊接热影响区（ＨＡＺ）发生断裂事故的一套３１６Ｌ不锈钢设备进行了失效分析。认为该设备的断裂属于ＳＣＣ,焊接的质量差是造成断裂的根本原因。     

铝合金搅拌摩擦焊接接头应力腐蚀研究进展

随着搅拌摩擦焊接应用领域的扩展,其焊接接头的应力腐蚀性能已成为人们关注的重要问题.论述了近年来国内外铝合金搅拌摩擦焊接接头应力腐蚀研究进展,并展望了发展前景.     

不锈钢的腐蚀分析

分析了不锈钢应力腐蚀开裂(SCC),点腐蚀、晶间腐蚀,腐蚀疲劳,缝隙腐蚀,以及不锈钢的腐蚀机理。     

锅炉进水管与套管焊接接头的应力腐蚀

本文对锅炉进水管与套管焊接接头腐蚀的原因进行了初步分析，指出其主要原因是ＡＰＣ类型的应力腐蚀，并从锅炉进水管与套管焊接接头的整体结构和焊接工艺两方面提出了改进的意见。     

晶界结构在不同热处理下对铝镁合金腐蚀规律的研究现状

铝镁合金是未来应用汽车领域发展具有很大潜力的一类重要材料.通常,在商品中的铝镁合金,镁的质量分数在0.5%～13%.汽车制造商通常选用镁的质量分数在4.5%以上,然而研究发现,当镁的质量分数超过3%的时候,会引起晶界间腐蚀,从而造成应力腐蚀开裂.此现象未见文献对其进行系统的分析和研究.本文主要介绍铝镁合金在不同的热处理...     

Stress Corrosion Cracking Study of Aluminum Alloys Using Electrochemical Noise Analysis

Stress corrosion cracking studies of aluminum alloys AA2219, AA8090, and AA5456 in heat-treated and non heat-treated condition were carried out using electrochemical noise technique with various applied stresses. Electrochemical noise time series data (corrosion potential vs. time) was obtained for the stressed tensile specimens in 3.5% NaCl aqueous solution at room temperature (27 °C). The values of drop in corrosion potential, total corrosion potential, mean corrosion potential, and hydrogen overpotential were evaluated from corrosion potential versus time series data. The electrochemical noise time series data was further analyzed with rescaled range (R/S) analysis proposed by Hurst to obtain the Hurst exponent. According to the results, higher values of the Hurst exponents with increased applied stresses showed more susceptibility to stress corrosion cracking as confirmed in case of alloy AA 2219 and AA8090.     

海面建筑用E36耐蚀钢与耐蚀实心焊丝焊接接头的抗腐蚀性能分析

分析了焊接接头不同区域的腐蚀行为,同时探讨了材料的夹杂物、微观组织及其化学成分对焊接接头耐腐蚀性能的影响。结果表明,焊接接头各个区域的耐蚀性有微小的差异存在,其中焊缝的耐蚀性最佳,母材次之,热影响区内的耐蚀性最差。夹杂物为焊缝中诱发点蚀的源头。     

Stress Corrosion Cracking of Turbine Disc and Rotor Alloys

Abstract

Investigations have been carried out to examine the stress corrosion behaviour of some medium strength low alloy steels in high purity wet steam and water. The alloys involved are used for the manufacture of steam turbine discs and rotors.

Stress corrosion cracking occurred in both 3% CrMo and 31/2% NiCrMoV steels. Crack growth rates were measured, after exposure in on-site rigs, for periods up to 20,000 h. The effects of applied stress, stress intensity, and strength level were studied in addition to microstructure. The possible role of certain non-metallic incluszons upon the cracking process is highlighted, as is the presence of chromium.     

Mechanism of Stress Corrosion Cracking of Al–Li Alloys

G.V. Akimov's concepts of the corrosion–electrochemical properties of aluminum alloys containing lithium are developed. It is found that binary Al–Li alloys are insusceptible to stress corrosion cracking, even though their dissolution rate under normal conditions can increase by up to 30 times because of the selective dissolution of lithium. The interaction of dislocations with phases formed upon heat treatments is demonstrated to play a determining role in the stress corrosion cracking of all the basic aluminum–lithium alloys, namely Al–Li, Al–Li–Cu, Al–Li–Cu–Mg, and Al–Li–Mg alloys. The stress corrosion cracking of both binary aluminum–lithium alloys and alloys which are in addition alloyed with copper and magnesium has mainly a dislocation–electrochemical mechanism. The effect of electrochemical factors is well represented by the difference in the magnitude between the pitting initiation potential and the repassivation potential.     

23MnNiMoCr54钢焊缝低应力断裂原因分析

针对生产过程中一批23MnNiMoCr54圆环用钢经闪光对焊后焊缝发生低应力断裂的问题,利用扫描电镜和能谱仪对焊缝的断口形貌及微观成分进行了分析。结果表明:在焊缝区域内存在着局部未熔区以及铸造疏松组织和二次裂纹等缺陷,这是导致试样低应力断裂的根本原因。     

采用自制简易装置评定高强铝合金的应力腐蚀性能

设计了一种用于铝合金应力腐蚀性能对比的简易快速的实验装置.对7075铝合金和添加1%锂的7075合金在不同热处理状态下的应力腐蚀倾向进行了评定和对比.实验结果表明, 这种简易装置用于应力腐蚀评定,比较好地再现了已知的高强铝合金的应力腐蚀规律.还用这一装置对锂元素和热处理状态对铝合金应力腐蚀的影响进行了研究.     

新锆合金在两种不同介质中的耐蚀行为

研究了几种Ｚｒ－Ｓｎ－Ｎｂ－Ｆｅ－Ｃｒ新锆合金在４００℃,１０．３ＭＰａ及在３６００℃,１８．６ＭＰａ含７＊１０＾－５锂的氢氧化锂水中的耐蚀行为; 用ＴＥＭ和ＳＥＭ对合金中的第二相的结构和组合进行了分析。     

镁合金应力腐蚀开裂研究进展

镁合金在腐蚀性环境中常常发生应力腐蚀开裂失效问题。论述了镁合金应力腐蚀开裂的机理,以及阳极溶解、氢致开裂、应力作用等主要诱因,从提高成分品质、进行表面处理、降低及消除应力、优化组织控制(尤其是组织超细化)等方面简介了国内外应对镁合金应力腐蚀开裂的最新措施,并指出了目前在提高镁合金抗应力腐蚀开裂性能的研究发展方向及亟待解决的问题。