含钼耐候钢的腐蚀性能

通过显微组织观察、周浸加速腐蚀实验、锈层微观分析、锈层交流阻抗特征分析等方法,研究了合金元素钼含量对耐候钢腐蚀性能的影响.合金元素钼可以促进钢中贝氏体组织的形成,促使锈层更加致密,对钢基体具有更好的保护性,有利于提高钢的耐腐蚀性能.随着钢中钼含量的增加,实验钢锈层的腐蚀电位正移,自腐蚀电流密度减小,锈层的阳极溶解反应受到明显阻碍,锈层具有更好的保护性.      

环境温度对船用耐蚀钢腐蚀行为的影响

 采用国际海事组织（IMO）模拟油轮货油舱内底板环境试验方法,对比分析了传统船板和耐腐蚀船板的腐蚀失重与腐蚀形貌,深入研究了环境温度对船用耐蚀钢腐蚀行为影响规律。结果表明,环境温度对船板腐蚀行为存在显著影响,随着环境温度（30~50℃）的升高,点蚀坑的数量逐渐增多,点蚀坑深度先增大后减小,在45℃时达到峰值。2种钢点蚀行?畋鸾洗螅炒甯值闶纯拥纳疃戎本侗龋╤/D）随环境温度的增大而增大,而耐蚀船板则呈现逐步下降的趋势。耐蚀合金元素的加入有效降低了船板钢在不同温度下的腐蚀速率,减小了钢的点蚀坑数量,改善了点蚀坑的扩展方式。即点蚀坑由纵向深度方向扩展,转为横向表面方向扩展,有效提高了船板的安全性。     

夹杂物对E36级船板钢货油舱下底板点蚀行为的影响研究

为了探究夹杂物在低pH值、高浓度氯离子腐蚀环境下诱发点蚀的作用机理,本研究利用pH值0.85的10％NaCl溶液,模拟E36级船板钢货油舱下底板腐蚀环境;采用扫描电镜(SEM)、X射线能量色散谱分析(EDS)、夹杂物原位观察等手段,分析不同类型、尺寸、形状夹杂物对点蚀行为的影响.试验结果表明:耐腐蚀钢中存在MnS﹑Ti...     

耐蚀钢中铜元素对耐蚀性的影响规律探讨

采用浸泡腐蚀试验、锈层XRD分析、环境扫描显微镜(SEM)和电化学分析等方法,研究了不同Cu含量的油轮耐蚀钢在模拟原油船货油舱环境下的腐蚀规律和机理。结果表明:Cu含量增加,油轮钢耐腐蚀性能增加;短期浸泡腐蚀过程中,铜元素的加入可显著提高腐蚀电位、降低腐蚀电流密度;长周期浸泡腐蚀过程中,铜元素改善了产物膜结构和致密度,提高了与基体的结合度,从而有效抑制了基体的进一步腐蚀,提高了低合金钢长周期浸泡的耐蚀性能。     

原油船货油舱耐蚀钢的发展

概述了原油船货油舱的腐蚀情况和主要防护措施,并介绍了货油舱耐蚀钢发展历史、技术应用和国内外产品研制情况。结合原油船货油舱的腐蚀特点和国际海事协会(IMO)的耐蚀钢标准,阐述了当前原油船货油舱耐腐蚀防护措施以及发展原油船货油舱耐蚀钢的必然趋势,并表明为应对国内外造船市场对原油船用耐蚀钢板的潜在需求,发展原油船货油舱用耐蚀钢产品及其产业化应用技术已经刻不容缓。此外,针对原油船货油舱耐蚀钢的开发和应用特点,阐述了耐蚀钢在产业化应用过程中的实际腐蚀环境检验和效果验证的必要性。     

强酸性氯离子环境下低合金钢的点蚀行为

 参照国际海事组织（IMO）发布的《油轮货油舱耐蚀钢性能标准》中所规定的模拟内底板试验方法,对比研究了在强酸性高氯离子浓度的环境下,传统低合金钢和耐蚀低合金钢的腐蚀速率及点蚀行为随温度变化的规律。试验结果表明,添加铜、镍元素的耐蚀低合金钢腐蚀速率较传统低合金钢最高降低了90%以上,并且具有优于传统低合金钢的抑制点蚀增殖、扩展的性能。耐蚀低合金钢表面及点蚀坑内部分布有白色颗粒,为铜元素的再沉积所致。该纯铜颗粒分布于试验钢表面可以有效提高钢的腐蚀电位,在点蚀坑内部的富集可以有效抑制点蚀坑在深度方向上的扩展。     

不同显微组织钢板耐蚀性研究

采用周浸加速腐蚀试验对Q235B、Q345B低合金钢以及X70管线钢的耐蚀性能进行对比研究,并采用OP、SEM等分析方法对表面以及剖面锈层形貌进行分析。结果表明:不同显微组织钢的耐蚀性能存在显著差异,随着珠光体含量的增加,低合金钢的耐蚀性能逐渐降低。X70管线钢由于其显微组织主要为针状铁素体+粒状贝氏体,组织均匀,相间电位差较小,其耐蚀性能明显优于铁素体+珠光体型的低合金钢。     

低合金耐候钢在含氯离子环境中的腐蚀行为

利用干湿周浸加速腐蚀实验对比研究了低合金钢A588和SPA-H在含氯离子环境下腐蚀行为,并利用金相显微镜、扫描电镜、X射线衍射和电子探针等方法分析了Ni、Mn对于低合金钢腐蚀行为的影响.结果表明:实验钢锈层中的物质主要由α-FeOOH、γ-FeOOH和Fe₃O₄组成,但其含量存在差异;Ni元素在内锈层含量高于外锈层,Mn元素在锈层的孔洞处富集;内锈层的致密程度高于外锈层;提高合金元素Mn和Ni的含量,可以提高内锈层的致密性,从而提高低合金钢的耐蚀性能.      

重稀土E36高强船板钢耐腐蚀性试验及分析

为探究重稀土元素对E36高强船板钢耐腐蚀性能的影响,通过实验对常规E36钢及添加了重稀土的E36RE钢分别进行了模拟耐海水腐蚀试验,分析重稀土元素的加入对E36钢耐腐蚀性能的影响.试验结果表明:常规E36钢的腐蚀速率和E36RE钢的腐蚀速率的比值达到1.662∶1,E36RE钢腐蚀速率比E36钢降低的比例达到了40％....     

集装箱用高强耐候钢组织及腐蚀行为研究

利用动态相变仪分析Nb-Ti微合金化高强耐候钢在不同冷却速率下的显微组织变化规律,采用控轧控冷工艺获得高强热轧钢板,并通过72 h周期浸润腐蚀试验和腐蚀锈层元素分布分析对高强热轧钢板的腐蚀行为进行研究.结果表明：当冷却速度小于1℃/s时,变形后的奥氏体转变为铁素体、珠光体和贝氏体;随着冷却速率的增加,珠光体和铁素体逐渐减少并直至消失,贝氏体数量增加;采用控轧控冷工艺获得的高强钢板屈服强度为704 MPa,抗拉强度为753 MPa,伸长率为20.2%,-40℃低温冲击吸收功平均值为121 J;腐蚀后的实验钢与Q345B碳钢的相对失重率为52.11%,其表面锈层与铁基体结合紧密,表明Nb-Ti高强耐候钢在工业大气腐蚀环境下具有良好的耐腐蚀性能.     

09CuPTiRE钢耐候性能及腐蚀过程研究

通过浸渍干湿循环加速腐蚀试验 ,采用失重法测量年蚀率 ,SEM观察腐蚀产物的表面形貌和断面形貌 ,XRD测定腐蚀产物的物相组成 ,电化学阻抗谱仪测定锈层的交流阻抗谱 ,研究了0 9CuPTiRE耐候钢与Q2 3 5、鞍钢耐候钢和日本耐候钢三种参比钢的耐候性能及腐蚀过程 .结果表明 :0 9CuPTiRE钢的耐候性能显著优于Q2 3 5钢 ;Q2 3 5钢锈层为一层网状、疏松且有大量纵向交错裂纹和孔洞的锈层 ,而 0 9CuPTiRE及另两种耐候钢的锈层分内外两层 ,外层与Q2 3 5钢锈层相似 ,内层均匀、连续、致密 ;Q2 3 5钢的腐蚀过程受活化控制 ,即受控于金属离子进入溶液的速度 ,而0 9CuPTiRE钢的腐蚀过程既受活化控制 ,由于保护锈层的存在还受氧的扩散控制 .     

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.     

Cr-Ni-Cu系低合金铸钢在海洋大气环境中的腐蚀行为

为满足桥梁支座用铸钢在海洋大气环境下的耐蚀性要求,设计了2种成分的Cr-Ni-Cu系耐腐蚀低合金铸钢。采用周浸加速腐蚀试验、实地大气暴露试验考察试验钢在海洋大气环境中的腐蚀行为,并结合扫描电镜、XRD、电化学手段分析了合金元素对锈层和电化学行为的影响。结果表明,2种成分的Cr-Ni-Cu系低合金铸钢的耐蚀性均较好,随着时间延长,耐蚀铸钢腐蚀率下降并达到稳定,而对比钢种20MnSi腐蚀率保持下降趋势,未达到稳定状态。周浸腐蚀316h后耐蚀铸钢与20MnSi腐蚀率差距变小;Cr元素在内锈层中呈条带状富集,有效阻碍了Cl-的扩散,Ni的加入提高钢的自腐蚀电位,促进γ-FeOOH向α-FeOOH的转化,增加锈层稳定性;Cr、Ni、Cu的复合加入增大了铸钢的电荷传递电阻,提高了耐蚀性。     

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The corrosion environment of cargo oil tank (COT) was simulated according to performance standard for corrosion resistant steel of IMO in this paper, to study the corrosion behavior of two different ship hull steel on the upper deck of COT. The results showed general corrosion in wet-dry environments contained H2S, the corrosion rate of conventional E36 steel reached 0??4mm/a. The addition of Cu and Ni improved the formation of the stable phase ??-FeOOH, which decreased the defect in the rust and made the rust more compact. Inclusions such as CaO and CaS formed in the Ca treated ship steel, which dissolved under the corrosion media and alkaline product generated, the alkaline product increased the pH value of the liquid film on the surface of steel and slowed down the corrosion rate of steel.     

Effect of microstructure on corrosion behavior of low carbon high chrome steel

The two types of microstructure of low carbon and high chromium steel (5Cr) were obtained through the test smelting, rolling and quenching after rolling.Corrosion performance of 5 mass%Cr steel and Q235 steel were researched by means of cyclic wetting and drying corrosion test in 2 mass% NaCl solution.Corrosion behavior and corrosion rust layers were analyzed by OM, SEM, EDS, XRD, cyclic wetting and drying corrosion tester and electrochemical testing. The results show that after the specimens were immersed and etched in 2 mass% NaCl solution for 72h, the different microstructures of 5Cr steel have great influence on the resistance to chloride ion corrosion. B+F+M microstructure of 5Cr steel shows lower corrosion rate than Q235 steel, 5Cr steel with martensite microstructure also shows lower corrosion rate than Q235 steel. Corrosion susceptibility of 5Cr steel with martensite structure is weaker than complex organization.The stratification of chromium oxide, oxyhydroxide, and iron oxide exists in the chromium- containing steel rust layer, in which the Cr enrichment maximum value is 17 mass%, and the lowest is 1 mass%.Lath martensite formed by quenching process makes the corrosion potential rise, ??- FeOOH and ??- FeOOH form. Bainite+ferrite phase and adverse phenomenon of Cr steel may cause the poor corrosion resistance.     

碳含量和组织类型对低合金钢耐蚀性的影响

 研究了碳含量不同和显微组织不同的低合金钢的耐腐蚀性能和腐蚀行为,并和商业耐候钢09CuPCrNi做了相应的比较。在碳含量比较低的情况下,组织类型对试验钢的耐蚀性影响不大;碳含量比较高时,单相贝氏体钢的耐蚀性优于由铁素体、渗碳体(珠光体)等构成的复相组织钢。轧后水冷时,不同碳含量的钢耐蚀性差别不大;轧后空冷时,碳含量低的钢的耐蚀性优于碳含量较高的钢。用扫描电镜对锈层进行观察,可以看出耐蚀性较好的试样在腐蚀后期形成了较致密的内锈层。碳的质量分数分别为0.03%和0.1%的钢水冷后的平均腐蚀速率相差很小,但从微观角度看其点蚀发展趋势不同。加速腐蚀5个周期后,w(C)为003%的水冷钢中蚀坑尺寸不再增加,而w(C)为01%的钢中蚀坑尺寸仍有增加趋势。     

Effect of Micro-Area pH Value on Formation of Different Rust Phases of Weathering Steel in Initial Corrosion Period

The formation of protective rust layer of atmospheric corrosion resistance was discussed for weathering steel.The rust layers of experimental steels were made by using an accelerating industrial atmospheric corrosion test of dry-wet cyclic immersion.Furthermore XRD were used to measure and analyze the rust layers.The initial corrosion processes below thin water film were observed and the changes of micro-area pH value were measured.The results are as follows:The corrosion processes of P-RE weathering steel are obviously different from those of carbon steel.The surface of P-RE weathering steel rapidly forms α-FeOOH and the micro-area pH value is above 5.4 during the initial corrosion period.While the component of the rust layer for the carbon steel is mainly Fe3O4 and the micro-area pH value is below 3.8.     

Cr对低合金钢在流动NaCl溶液中耐蚀性的影响

对碳钢和Cr含量不同的实验钢在流速为0.8m/s的流动的3.5％(质量分数)NaCl溶液中的腐蚀行为进行研究,最长腐蚀周期为192h.对4种实验钢的腐蚀失重进行了比较,并利用动电位极化曲线、SEM、EPMA和TEM等分析手段,对实验钢表面形成锈层的特征进行了系统研究.结果表明,含Cr实验钢的腐蚀失重低于碳钢,并且随Cr的质量分数由0.5％提高至2％,腐蚀失重亦降低.Cr元素在内锈层中的富集是含Cr钢耐蚀性改善的重要原因.这种富集可使腐蚀产物颗粒获得细小的尺寸,致密内锈层形成的原因就是由于这种尺寸细小的腐蚀产物的形成,使内锈层的保护性获得明显的改善.     

Effect of different deoxidation methods on local corrosion resistance of low alloy high strength steel

Al- deoxidation and Zr- Ti compound deoxidation were used to deoxidize high- strength low- alloy steel. The microstructure and inclusions of the steel under different deoxidation conditions were observed by optical microscope and scanning electron microscope.According to the Russian GOST 9. 911??89 standard, the indoor accelerated corrosion test and electrochemical test were carried out to investigate the influence of different deoxidation methods on the local corrosion stability of high- strength low- alloy steels. The results show that the inclusions formed by the two deoxidation methods are all fine oxides. The inclusions formed in the Al- killed samples are spherical or linear, whereas the inclusions formed in the Zr- Ti- killed samples are uniformly distributed in spherical shape. The local corrosion resistance of Zr- Ti composite deoxidation samples in seawater is better than that of conventional Al deoxidation samples. The average corrosion rate of Zr- Ti composite deoxidation steels is reduced by 17. 27%.Zr- Ti compound deoxidation can effectively control the type, size and distribution of inclusions, the size is mainly distributed in 1-5??m.The Zr- Ti composite oxide is dispersed in the matrix, which can reduce the sensitivity of pitting corrosion and improve its stability to seawater localized corrosion.     

Corrosion Behaviour of New Railway Axle Steels

Corrosion behaviour of two newly developed axle steels (MS3 and MS6) is critically analysed and compared with that of the conventional railway axle steel with respect to the rust formed on the surface and microstructure of the steels. The microstructure of all three steels is ferrite–pearlite. Immersion, salt-fog exposure and dynamic polarisation tests in 3.5 wt% NaCl solution are carried out. New steels have much better mechanical properties and comparable corrosion resistance in immersion and dynamic polarisation test and much better corrosion resistance in salt-fog exposure test than that of the conventional axle steel.