Influence of the Flux Coating with Different Cu/Al Ratios on X80 Pipeline Steel Welding Seam

In this study, X80 pipeline steel was welded by self-made welding electrode with different Cu/Al ratios in flux coating. The microstructure and mechanical properties of X80 steel welding seam were investigated by optical microscope, energy-dispersive spectroscopy, scanning electron microscope, X-ray diffraction. The hardness, tensile and impact tests were carried out. The electrochemical corrosion and uniform corrosion properties of welding seam were also studied in sulfide environment. The experimental results reveal that alloying agent such as Cu and Al can transform to the welding seam very well. Furthermore, the microstructure and properties of welding seam can be improved effectively with a suitable Cu/Al content ratio. By reducing the Cu/Al content ratio, the mechanical properties and corrosion resistance properties increase initially and then decrease. When the Cu/Al ratio is maintained at 6:2 in the flux coating, the welding seam has more acicular ferrite, resulting in the best mechanical properties and corrosion resistance. Moreover, the addition of Cu and Al elements does not result in a serious deterioration of the resistance to HIC.     

经济耐候钢的研究

系统研究了Mn、Cu含量及腐蚀环境体系对协同作用的影响,并利用电化学测试、扫描电镜、XRD等材料分析技术对带锈电极的腐蚀行为、锈层组成、结构和性质进行了深入分析,阐述了Mn-Cu合金化协同作用的机制;利用Mn-Cu合金化的协同作用,成功开发出Mn-Cu型经济耐候钢和实现工业化试生产。实验表明：热轧Mn-Cu钢具有良好的耐候性,其耐候性略优于传统的09CuPTiRE和SPA-H耐候钢。     

钛合金表面硬化与固体润滑处理层的电化学腐蚀行为研究

分别利用等离子氮化技术和离子束增强沉积(IBED)技术使钛合金表面获得硬质抗磨层和MoS2，MoS2-Ti固体润滑膜层。通过电化学测试技术研究了膜层和钛合金基材在含Cl^-介质中的抗蚀性能和接触腐蚀敏感性：研究结果表明：Ti与MoS2的复合改善了MoS2膜的环境适应性，MoS2—17Ti复合膜层与钛合会接触相容；IBED TiN较钛合金电化学活性低，阳极极化行为与Ti6Al4V合金相近，与钛合金基体间电偶腐蚀敏感性低；钛合金等离子氮化处理层在NaCl水溶液中无论处于自然腐蚀电位还上弱阳极极化状态，均较钛合金电化学活性低，且与钛合金基体间电偶腐蚀敏感性低。     

Effect of cerium on microstructure,mechanical properties and corrosion properties of Al-Zn-Mg alloy

The effects of trace Ce on the microstructure,mechanical properties and corrosion resistance of Al-Zn-Mg alloy were studied by means of metallographic analysis,scanning electron microscopy(SEM),mechanical tensile test,slow strain rate tensile test,cyclic polarization curve test,electrochemical impedance spectroscopy test and anodic oxidation test.The results show that the addition of trace Ce has little effect on the strength of Al-Zn-Mg alloy,but can significantly improve the corrosion resistance of the alloy;The mechanical properties and corrosion resistance of the alloys decrease significantly with the addition of excessive Ce;the addition of 0.04 wt%Ce can reduce significantly the self-corrosive current density of AlZn-Mg alloy and increase obviously passivation film resistance of the alloy.The stress corrosion sensitivity index decreases from 0.612 to 0.219,which improves the corrosion resistance properties significantly.     

Electrochemical Studies on the Passive Film Integrity of Titanium Under Seawater Biofilms

An attempt was made to explore the electrochemical behavior of Titanium (Ti) condenser material under seawater biofilms. The Ti specimens with seawater biofilm were subjected to microscopic examinations and electrochemical studies such as cyclic voltammetry (CV), electrochemical impedance spectroscopy, open circuit potential monitoring and anodic polarization. The CV curves of Ti specimens with 15 days old biofilms showed characteristic redox peaks with high cathodic current indicating the electroactive biofilms. Similarly impedance spectra clearly showed two time constants with decrease in charge transfer resistance and increase in capacitance as the biofilms growth increased on the Ti specimens. Polarization curve showed the ennoblement of corrosion potential and increase in passive current with the growth of biofilm on Ti. Based on these data, a possibility of Ti passive film integrity loss by electroactive seawater biofilms has been discussed.     

Titanium Containing High Strength Sulfuric Acid Corrosion Resistant Steel

Ti containing low alloy steel free of Sb is found to have higher strength than and equivalent sulfuric acid corrosion (SAC) resistance to traditional SAC resistant steels in Cu? Cr? Sb system. SAC resistance of the Ti containing steel was investigated with potentiodynamic polarization, linear polarization resistance, electrochemical impedance spectroscopy, and weight loss measurements in a solution of 20 wt% H₂SO₄ at 20°C. All measurements confirm that Ti addition is suitable for designing high strength SAC resistant steels.     

NaCl+HCl溶液中Ce对双相不锈钢腐蚀行为的影响

为了研究酸性NaCl溶液中双相不锈钢的耐腐蚀性能,以含微量稀土Ce的UNS S31803双相不锈钢为研究对象,采用电化学阳极极化和交流阻抗相结合的方法测试其在NaCl+HCl混合溶液中的耐腐蚀性能。利用扫描电镜(SEM)观测腐蚀后的形貌特征,采用电子探针(EPMA)检测合金元素与杂质元素的分布特征,分析Ce元素的加入对双相不锈钢电化学腐蚀行为的影响机制。结果表明,钢中存在两相的选择性腐蚀并伴有局部点蚀,其中铁素体相是腐蚀较严重的相;阳极极化测试与交流阻抗测试结果相吻合,Ce拓宽了试验钢的钝化区间;Ce通过净化钢液、降低S和P元素在相界的偏聚及使Cr、Ni和Mo等合金元素在两相中的分布更均匀等作用,提高了钢的耐腐蚀性能。     

Effects of Cu on Corrosion Resistance of Low Alloyed Steels in Acid Chloride Media

The corrosion resistance of two kinds of low alloyed steels was studied according to the test procedures for qualification of corrosion resistant steel for cargo oil tanks issued by International Maritime Organization.The results indicated that the addition of Cu improved the corrosion resistance of the NS-D36 steel to more than three times that of the conventional D36 steel in the strong acid solution containing chloride(10% NaCl,pH=0.85).The anodic polarization behavior of the copper-bearing steel was studied by polarization curves and electrochemical impedance spectroscopy(EIS),and alloying element Cu showed beneficial effects including an active potential range,low current density and high transfer resistance of electric charge.The rust layer was analyzed by scanning electron microscopy(SEM)and Auger electron spectroscopy(AES),and the results pointed out that the mechanism of copper′s beneficial effects was based on the suppression of anodic dissolution by metallic copper re-deposition on the steel surface immersed in the strong acid chloride media.     

Corrosion Behavior of Ultra Fine Grain Copper Produced by Accumulative Roll Bonding Process

In this study the effect of microstructure changes on the corrosion behavior of pure tough pitch copper in 3.5 % NaCl solution with pH = 5.5 at ambient temperature was studied. Accumulative roll bonding process as severe plastic deformation was applied up to 8 cycles to produce the ultrafine grain copper. For corrosion resistance investigations, the polarization and electrochemical impedance spectroscopy was used. Corrosion morphologies analyzed by FE-SEM microscopy after polarization and immersion tests. Results show the minimum corrosion resistance for cycle 2 and maximum corrosion resistance for cycle 8. Corrosion rate of copper decreased after it was rolled for forth time. The corrosion degradation in cycle 8 was uniform and it was intergranular for sample of cycle 2 and unrolled counterpart. The higher corrosion rate in cycle 2 was attributed to unstable microstructure and the uniform corrosion of cycle 8 was due to ultra fine grain formation.     

冷却水对H型钢表面氧化铁皮耐蚀性能的影响

采用光学显微镜对试验样品表面进行观察和分析,利用水质分析仪对氧化铁皮中残留的腐蚀性介质的浓度进行测定。通过极化曲线和电化学阻抗等电化学测试方法,研究了H型钢样品表面氧化铁皮的耐腐蚀性能变化。结果表明:水冷样品表面锈蚀严重,原因是其表层氧化铁皮中阴离子含量高,腐蚀介质易渗入氧化膜内层,导致耐蚀性能降低。     

Electrolytic Corrosion of Titanium Carbonitride Composites

The corrosion properties of TiCN, TiCN – AlN, and (TiCN – AlN) – (Fe – Cr) ceramics as well as those of the individual components TiN and TiC in a 3% NaCl solution have been investigated. The kinetics and the mechanism of anode dissolution of metals and oxidation of specimens have been studied by using polarization curves, chemical and x-ray phase analyses, Auger electron spectroscopy, and scanning electron microscopy (SEM). TiCN and TiCN – AlN composites have been found to be the most corrosion-resistant. The presence of a metallic binder in the titanium carbon nitride somewhat decreases the corrosion resistance of the ceramics. On the whole, however, the ceramics developed boast a significantly higher corrosion resistance than that of structural steel.     

Investigation of the processes of obtaining plastic treatment and electrochemical behaviour of lead alloys in their capacity as anodes during the electroextraction of zinc I. Behaviour of Pb---Ag, Pb---Ca and PB---Ag---Ca alloys

The influence of the mode of obtaining and plastic treatment of binary Pb---Ag and Pb---Ca, and ternary Pb---Ag---Ca alloys (used as anodes in Zn electro-extraction from sulphate electrolytes) on their electrochemical behaviour and corrosion resistance is studied.It has been established that the rolled Pb---Ag alloys possess a higher corrosion resistance and lower anodic polarization compared to the cast lead-silver ones due to the structural fineness and homogeneity of the plastic deformed anodes. The plastic deformation of the ternary alloys with calcium content of 0.06% causes Pb₃Ca precipitation in the solid solution. The hot-rolled alloys form an solid solution of Pb₃Ca with fine-grained structure, deformed through the rolling direction. The cold-rolled alloys possess clearly expressed oriented structures also through the rolling direction.Cast and plastically deformed Pb---Ca anodes possess better electrochemical and corrosion characteristics than pure Pb but a considerably higher anodic polarization and lower corrosion resistance than Pb---Ag alloys. Both Pb---Ca systems, with a calcium content of 0.08 and 0.11 % are very appropriate for the preparation of ternary Pb---Ag---Ca alloys. These alloys (Pb---Ag 0.5 %-Ca 0.11 %) possess better electrochemical and corrosion characteristics than binary Pb---Ca ones. Only ternary rolled alloys have equal corrosion and electrochemical properties to those of the alloy Pb---Ag (0.75%–1.0%) used in practice.     

稀土铈对22MnCrNiMo钢耐腐蚀性能的影响

为了研究稀土对系泊链钢耐蚀性能的影响,冶炼铈含量不同的稀土系泊链钢,利用稀土在钢中的有利作用,力求进一步提高系泊链钢的耐蚀性能。试验用22MnCrNiMo稀土钢由10 kg真空感应炉冶炼,热轧成17 mm板坯,经930 °C二次淬火加620 °C回火处理,通过质量法、极化曲线法和交流阻抗法研究铈对22MnCrNiMo钢耐腐蚀性能的影响。结果表明,添加稀土铈后,不同铈含量试验钢的抗腐蚀性能均有所提高,钢中铈的最佳质量分数为0.143%。此含量下,试验钢组织的均一性最佳,钢中夹杂转变为稳定性高的稀土类球状夹杂,使得试验钢在任一浸泡周期内的腐蚀速率均为最小,除锈后的腐蚀痕迹最轻;容抗弧半径达到最大,即反应电阻到达最大;阳极极化曲线位于其他试验钢阳极极化曲线的左边,即阳极电流密度变小,反应阻力增大。所以铈可以提高22MnCrNiMo钢耐腐蚀性能,当钢中铈的质量分数为0.143%时,试验钢的抗腐蚀性能表现最佳。     

Investigation of the processes of obtaining plastic treatment and electrochemical behaviour of lead alloys in their capacity as anodes during the electroextraction of zinc I. Behaviour of PbAg, PbCa and PBAgCa alloys

The influence of the mode of obtaining and plastic treatment of binary PbAg and PbCa, and ternary PbAgCa alloys (used as anodes in Zn electro-extraction from sulphate electrolytes) on their electrochemical behaviour and corrosion resistance is studied.It has been established that the rolled PbAg alloys possess a higher corrosion resistance and lower anodic polarization compared to the cast lead-silver ones due to the structural fineness and homogeneity of the plastic deformed anodes. The plastic deformation of the ternary alloys with calcium content of 0.06% causes Pb₃Ca precipitation in the solid solution. The hot-rolled alloys form an solid solution of Pb₃Ca with fine-grained structure, deformed through the rolling direction. The cold-rolled alloys possess clearly expressed oriented structures also through the rolling direction.Cast and plastically deformed PbCa anodes possess better electrochemical and corrosion characteristics than pure Pb but a considerably higher anodic polarization and lower corrosion resistance than PbAg alloys. Both PbCa systems, with a calcium content of 0.08 and 0.11 % are very appropriate for the preparation of ternary PbAgCa alloys. These alloys (PbAg 0.5 %-Ca 0.11 %) possess better electrochemical and corrosion characteristics than binary PbCa ones. Only ternary rolled alloys have equal corrosion and electrochemical properties to those of the alloy PbAg (0.75%–1.0%) used in practice.     

氮元素对Cr13超级马氏体不锈钢组织及性能的影响

摘要：为了提高超级马氏体不锈钢的性能以满足油气开采的使用要求,在Cr13超级马氏体不锈钢中添加质量分数为0.065%的N元素,并采用金相观察、SEM、拉伸试验、电化学测试等方法,研究N元素对Cr13超级马氏体不锈钢组织、力学性能及耐蚀性能的影响。研究发现,N元素能细化原奥氏体晶粒、对组织中的回火马氏体有一定的“短化”作用,并且能有效减少组织中的δ铁素体、增加奥氏体的含量。在力学性能方面,适量的N元素因可以细化奥氏体晶粒和短化马氏体从而增加晶界和亚晶界,所以能有效提高试验钢的屈服强度和抗拉强度。耐蚀性能方面,电化学实验表明,适量的N元素能提高钝化膜的保护能力和再钝化能力,所以在一定程度上能有效提高试验钢的耐蚀性能。     

Corrosion resistance of cermets based on titanium nitride

Conclusions The corrosion resistance of the cermets based on TiN with (Ni, Mo, Cr)-binder containing 10–15% Cr, is higher than that of KKhN-15 alloy and MNTs-20 German silver in solutions of acids: 5% HCl, 7% HNO₃ and 10% H₂SO₄.The resistance of the cermets based on titanium nitride is 5% HC1 decreases in the sequence: TiN-Cr > TiN-Ni, Mo, Cr > TiN > TiN-Ni, Cr > TiN-Ni, Mo > TiN-Ni.The corrosion resistance of the TiN-Cr cermets is slightly higher than the resistance of TiN. This is associated with the formation of the double nitride (Ti, Cr)N.Alloying theTiN-(Ni, Mo) cermet with 10–15% chrome results in high corrosion resistance and satisfactory physicomechanical properties.The corrosion resistance of the alloys with a high binder content (>25%) decreases as a result of its preferential dissolution which leads to separation of the titanium nitride grains. In addition to selective dissolution of nickel and molybdenum, the corrosion process in these alloys is also determined by dissolution of chrome.Translated from Poroshkovaya Metallurgiya, No. 1(337), pp. 77–81, January, 1991.     

氧化性杀菌剂对X70管线钢电化学腐蚀的影响

采用动电位极化和电化学阻抗方法，研究了X70管线钢在加入不同浓度氧化性杀菌剂(二氯异氰尿酸钠)的层流冷却水中的电化学腐蚀行为。极化曲线表明，随着层流冷却水中加入氧化性杀菌剂浓度的增大，X70管线钢的腐蚀电流密度(Icorr)呈逐渐上升的趋势。EIS结果表明，随着氧化性杀菌剂浓度的增大，电荷转移电阻逐渐减小，电化学反应的...     

Comparative Study on Thermodynamical and Electrochemical Behavior of Al（88）Ni6La6 and Al（86）Ni6La6Cu2 Amorphous Alloys

Two amorphous ribbons with the compositions of Al88Ni6La6 and Al86Ni6La6Cu2 were made using the melt-spun method,and their thermal response and electrochemical behavior were studied comparatively.Differential scanning calorimetry（DSC）and electrochemical polarization measurements indicated that Al86Ni6La6Cu2 exhibited slightly higher crystallization temperature（Tx）,lower melting point（Tl）and better corrosion resistance in 0.01 mol·L-1 NaCl alkaline solution.These results demonstrated that Cu（2%）addition could slightly promote the glass forming ability,but it could greatly improve the corrosion resistance of Al88Ni6La6 alloy in 0.01 mol·L-1 NaCl alkaline solution.     

Influence of crystallization on corrosion resistance of Al86Ni6La6Cu2 amorphous alloy

The influence of crystallization on the corrosion behavior of Al86Ni6La6Cu2 amorphous alloy in 0.01 M NaCl solution was investigated by electrochemical techniques. The Al86Ni6La6Cu2 amorphous alloy was prepared by melt spinning method, and the partially and fully crystallized states were obtained by controlled annealing. The evolution of the crystallization process after annealing was characterized by differential scanning calorimeter （DSC） and X-ray diffraction. The polarization curves revealed that all samples exhibited spontaneous passivation. The fully amorphous Al86Ni6La6Cu2 sample exhibited the best corrosion resistance. Partial and full crystallization resulted in deterioration of corrosion resistance in comparison with that of the as-spun amorphous state.     

稀土Ce对1Cr18Mn8Ni5N不锈钢耐均匀腐蚀性能影响

利用电化学的极化曲线及交流阻抗技术研究了不同稀土含量的1Cr18Mn8Ni5N不锈钢在硫酸介质中的腐蚀行为。应用扫描电镜对试样的腐蚀形貌及夹杂物形态进行了观察,利用EDS对夹杂物成分进行了分析。结果表明:钢中加入稀土Ce可改变夹杂物形态,并使其交流阻抗的极化电阻增大,极化曲线的腐蚀电位正移,降低了腐蚀电流密度,抵制了均匀腐蚀,改善了1Cr18Mn8Ni5N不锈钢的耐蚀性。当钢中稀土Ce质量分数为0.022%时,1Cr18Mn8Ni5N不锈钢可获得最好的耐均匀腐蚀性能。