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介绍对最小名义屈服强度为450 MPa(65 kpsi)的抗硫化氢应力腐蚀管线管采用四点弯曲方法制备SSC试样,进行抗H2S应力腐蚀评价,超声波探伤、冲击性能试验和金相分析的试验过程。评价试验结果显示,该抗硫化氢腐蚀管线管SSC试样通过超声波探伤未发现裂纹及开裂。评价试验试样未有明显的性能降低,内部未有氢致裂纹,具有很好的抗氢渗入能力。试样表面状态局部的微腐蚀,为表面的均匀腐蚀,腐蚀产物为FeS。管线管组织均匀、晶粒度细小,能阻止氢的进一步扩展,对材料的抗硫化氢腐蚀性能有着重要的影响。 相似文献
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硫化氢应力腐蚀破裂(sulfide stress corrosion cracking,SSCC)是制约管线钢应用的主要因素.针对X80管线钢焊接接头进行恒位移硫化氢应力腐蚀试验研究,分别测得母材、焊缝和热影响区的应力强度因子门槛值KISCC和裂纹扩展速率da/dt.通过对X80管线钢焊接接头的金相显微组织、断口形貌观察以及硬度测试,分析了X80管线钢SSCC性能的影响因素.并对WOL试样进行了三维弹塑性有限元分析,得到裂纹尖端应力场分布和氢浓度的分布特征.结果表明,热影响区的KISCC最小,裂纹扩展速率最大,具有较差的抗应力腐蚀开裂的能力,其应力腐蚀试验结果与有限元数值分析相互验证. 相似文献
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20CrMo钢表面喷涂有机硅改性聚脲的腐蚀行为 总被引:1,自引:0,他引:1
通过在20CrMo钢试样上喷涂有机硅改性聚脲涂层,用粘结力测试仪和显微硬度计对涂层的粘结力和硬度进行测试,采用恒温井液浸泡试验和高温高压腐蚀试验测试了涂层的耐蚀性能,结合扫描电镜(SEM)观察腐蚀形貌,并计算腐蚀速率,采用慢应变速率拉伸试验(SSRT)对涂层抗应力腐蚀性能进行分析.结果表明:腐蚀后涂层与基体宏观附着良好,能有效阻止腐蚀溶液的渗透和侵蚀;20CrMo钢经过喷涂聚脲处理后,腐蚀速率减小了一个数量级,耐蚀性能提高;应力腐蚀条件下,喷涂聚脲试样的应变量和最大应力值比基体分别增加了22%和2.7%,断裂时间延长约6.5 h,延长了基材的使用寿命. 相似文献
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含钪Al-Mg合金的抗应力腐蚀和剥落腐蚀性能研究 总被引:8,自引:0,他引:8
采用GJB1742-1993中有关铝镁系合金的应力腐蚀和剥落腐蚀试验方法,研究了高镁Al-Mg合金中添加微量元素Sc后的抗应力腐蚀和剥落腐蚀性能,利用金相显微镜和透射电子显微镜观察了合金的显微组织.结果表明,该合金具有良好的抗应力腐蚀和剥落腐蚀性能,合金变形组织中均匀弥散分布着β(Mg5Al8、Mg2Al3)沉淀相,在晶界上未出现连续口相形成的网络,因此合金耐腐蚀性能优良. 相似文献
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基于线弹性断裂力学的方法,以SPV50Q钢材为研究对象,选用不同部位的M-WOL楔形张开加载预裂纹试样,对其在不同硫化氢体积分数及不同状态条件下的应力腐蚀开裂性能进行研究。测定出应力腐蚀裂纹扩展速率da/dt和应力腐蚀开裂临界强度因子K_(ISCC)。结果表明:随着硫化氢体积分数的减小,SPV50Q钢的应力腐蚀裂纹扩展速率da/dt降低,应力腐蚀临界应力强度因子K_(ISCC)增大。对SPV50Q钢进行热处理后在一定程度上能降低裂纹扩展速率da/dt,同时可提高硫化氢环境下的抗应力腐蚀开裂能力。 相似文献
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复合多防涂装在海水中的防护性能 总被引:8,自引:1,他引:8
介绍了油漆涂层,金属喷涂层,金属喷涂层/油漆封闭等13种复合多防涂装在静海和动海海水试验中的耐海水腐蚀性能,并对其耐腐蚀性能作了简要分析,进而选出最佳的涂装体系,实践结果表明,704+842+546环氧沥青,702+846+546环氧沥青,热喷A1涂层和喷A1+842+546环氧沥青4种涂装具有优良的耐静海海水腐蚀性能,环氧石英砂浆和热喷铝+843+546环氧沥青2种涂装具有优良的耐动海海水腐蚀性能。 相似文献
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Zn-Al系列高速电弧喷涂层电化学防腐性能研究 总被引:6,自引:3,他引:6
采用粉芯丝材和高速电弧喷涂技术制备高Al含量的Zn-26%Al涂层。通过电化学的方法测试涂层在5%NaCl溶液下的腐蚀行为,并与由实芯丝材纯Zn、纯Al及Zn-15%A1所制备的涂层作比较。结果表明:Zn-26%A1涂层在电解质溶液中表现出更优越的防腐性能。动电位极化测试结果说明zn-Al涂层随着Al含量的增加,其耐蚀性也提高。纯Al涂层的电化学腐蚀行为与其它涂层有明显差异,其腐蚀机理类似于点蚀。 相似文献
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Electrochemical corrosion behavior of arc sprayed Zn-Al coatings 总被引:2,自引:0,他引:2
Cored wires and high velocity arc spraying (HVAS) technique were applied to produce high Al content Zn-Al alloy coatings on low carbon steel substrates. The electrochemical corrosion behaviors of Zn, Al and Zn-Al coatings were studied with potentiodynamic measurement in 5 % NaCl solution. Compared with pure Zn, pure Al and Zn-15Al coatings, Zn-26Al coatings show a higher corrosion resistance in salt solution. The potentiodynamic polarization tests show that the corrosion resistance of Zn-Al coatings increases as Al content is raised. Pure Al coating exhibits different electrochemical behaviors with other coatings. The corrosion initiated at the micro-pores of the coating and the underlying corrosion mechanism is very similar to that of the pitting corrosion. 相似文献
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本文使用电弧喷涂通过包套挤压+拉拔的方法制备的Zn55Al伪合金丝材成功的在Q235钢上喷涂出了Zn55Al涂层。通过扫描电镜和微区XRD研究了Zn55Al 伪合金丝材的显微结构。通过浸泡腐蚀实验和电化学方法研究了Zn55Al涂层、Zn15Al涂层和 Al涂层的腐蚀行为,并对比了三种涂层之间的差异。结果表明Zn55Al伪合金丝材由纯锌和纯铝组成,在整个成型过程中没有产生合金化。Zn55Al涂层由层片状的富锌相和富铝相组成。经过20天的浸泡实验,Zn55Al涂层形成了一层致密的钝化膜,比其他两种涂层有更好的耐腐蚀性。Zn55Al涂层的自腐蚀电位大约是-1.25v,高于Zn15Al涂层低于纯Al涂层和Q235基体.电偶腐蚀实验表明,Zn55Al涂层比Zn15Al涂层具有更好的点虎穴保护作用。这些结果说明Zn55Al涂层具有更好的耐腐蚀性和可以给Q235基体提供更强的电化学保护.本文也讨论了Zn55Al涂层的的腐蚀机理。 相似文献
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目的 明确废气再循环(Exhaust Gas Recirculation,EGR)单向阀阀片的腐蚀失效机理及防护涂层的失效过程,提高其服役寿命和可靠性。方法 利用电火花直读光谱仪、金相显微镜、体视显微镜、扫描电子显微镜和能谱仪等对EGR单向阀阀片断裂件进行失效分析,表征其化学成分、宏观腐蚀形貌、微观腐蚀形貌及腐蚀产物的元素分布,明确失效机制。采用电化学测试方法和浸泡试验对比研究了3种涂层防护的有效性,包括聚四氟乙烯(Polytetrafluoroethylene,PTFE)、淬火–抛光–淬火(Quench-Polish-Quench,QPQ)+PTFE和聚酰胺酰亚胺涂层,揭示EGR单向阀阀片的腐蚀失效机理及防护涂层的失效过程。结果 EGR单向阀阀片表面及断口腐蚀严重。随着浸泡时间的延长,3种涂层的吸水率增加。涂层电容增大而电荷转移电阻减小,涂层的防护性能降低。30 d的浸泡试验结果显示,聚酰胺酰亚胺涂层的耐蚀性最好,涂层剥落少,其次是PTFE涂层,而QPQ+PTFE涂层的耐蚀性最差,涂层大面积脱落且划痕处和阀片边缘出现了明显的腐蚀产物。结论 EGR单向阀阀片断裂的主要原因是腐蚀降低了单向阀阀片的承载能力,在应力作用下发生断裂而失效;受涂层厚度限制,3种涂层在浸泡24 h后均发生溶液渗入涂层到达涂层/金属基体界面的过程,涂层的耐渗水性能低。聚酰胺酰亚胺涂层和PTFE涂层可以作为防护涂层,能在一定程度上提高单向阀的服役寿命。 相似文献
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利用激光热辐射对X70管线钢表面进行渗铝处理,通过SEM观察了渗铝层表面和界面形貌,并对其结合界面的化学元素进行了EDS线能谱分析。对盐雾腐蚀后界面化学元素进行了EDS面能谱分析,用XRD分析了盐雾腐蚀前后渗铝层表面的物相,研究了渗铝层对X70管线钢抗盐雾腐蚀性能的影响。结果表明,激光热辐射渗铝处理后X70管线钢表层为氧化铝层,化学元素在表面和界面分布均匀,无富集现象,在结合界面处相互渗透,形成冶金结合形式;盐雾腐蚀后原始试样表面点蚀严重,形成全面腐蚀;渗铝处理后试样表面生成致密的Al2O3保护膜,阻止了腐蚀性介质Cl-离子和基体活性Fe的接触,提高了X70管线钢抗盐雾腐蚀能力。 相似文献
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Si和RE对热浸铝镀层耐盐水腐蚀性能的影响 总被引:2,自引:1,他引:2
对铝浴中添加Si和RE后批量热浸铝镀层的组织及耐盐水腐蚀性能的研究结果表明,铝浴中添加1 ̄7%Si和适量RE,明显提高镀层耐腐蚀性能,减少镀层腐蚀速度随溶液温度升高而增加的幅度,但加入过量稀土则降低镀层耐蚀性,文中探讨了合金元素提高镀层耐蚀性能的原因。 相似文献
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Mechanical Properties and Oxidation Behavior of a Graded (Ti,Al)N Coating Deposited by Arc-Ion Plating 总被引:2,自引:0,他引:2
Changjie Feng Mingsheng Li Li Xin Shenglong Zhu Fuhui Wang 《Oxidation of Metals》2006,65(5-6):307-327
A graded (Ti,Al)N coating was deposited on 1Cr–11Ni–2W–2Mo–V stainless steel for aero-engine compressor blades by arc-ion plating(AIP). The microstructure and the morphology of the graded coating were investigated using electron-probe microanalysis (EPMA), X-ray diffraction and scanning-electron microscopy. The mechanical properties of the graded coating were investigated and it was found that the microhardness and the wear resistance were similar to those of the monolithic (Ti,Al)N coating, but much better than those of a homogenous TiN coating. In addition, the adhesive strength and the thermal-shock resistance of the graded (Ti,Al)N coating were much better than those of the monolithic TiN and (Ti,Al)N coatings. The oxidation tests were performed at 600 and 700°C in air for 500 hr, and corrosion tests were carried out at 600°C under the synergistic effect of water vapor and NaCl for 20 hr. Compared to pure TiN, it was found that due to the incorporation of aluminum, a protective layer rich in alumina was formed on top of the graded (Ti,Al)N coating, which greatly improved the oxidation resistance and corrosion resistance of the coating. 相似文献
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Chunyu Wang Huanran Li Peng Zhang Hongyun Zhao 《Journal of Materials Engineering and Performance》2013,22(2):624-631
In this study, Ni-P coatings and sealing of the coatings by Ce-rich solution on Cf/Al composite surface for enhanced corrosion resistance are investigated. The corrosion resistance of uncoating sample in 3.5 wt.% NaCl solution was investigated and a comparison with Ni-P and Ce-sealed Ni-P coatings is given. Effect of Ce-sealing on Ni-P coating is discussed. The results of electrochemical measurements of corrosion performance of Cf/Al composites show that sealing of Ni-P coatings with Ce-rich solution can improve the corrosion resistance. The Ce-rich-sealed Ni-P coating has higher corrosion resistance than the coating without Ce, and the electroless plated Ni-P coating on composite surface has higher corrosion resistance than the bare sample, as evidenced by EIS and potentiodynamic polarization measurements. The microstructure of the Cf/Al composites and the two kinds of coatings (i.e., Ni-P coating and Ce-sealed Ni-P coating) were examined by scanning electron microscopy, energy dispersive spectroscopy, and transmission electron microscopy. The Ce-sealed Ni-P coatings on Cf/Al composite surface have a total thickness of ~11 μm of which 10 μm is the thickness of the Ni-P coating and ~1 μm is the thickness of the Ce-rich sealing. It shows that the selected area electron diffraction ring pattern of Ce-rich sealing on Ni-P plated composite is consistent with Ce6O11 or CeO2. X-ray photoelectron spectroscopy results show that Ce4+ was the dominant oxidation state for Ce-rich sealing on Ni-P plated composite. The Ce-sealing treatment on Ni-P coating has improved the corrosion resistance over and above the corrosion resistance offered by the Ni-P mono-coating to the bare substrate. 相似文献