新铜萃取剂萃取盐酸介质中铜的实验研究

采用新铜萃取剂N902对盐酸介质中铜的萃取进行了研究。考察了萃取剂、氢离子、氯离子、铜离子浓度及萃取时间的变化对铜萃取率的影响。结果表明,随着氢离子、氯离子浓度的增加,铜萃取率下降。当铜的浓度达8.5 g.L-1时,用30%的N902萃取盐酸介质中的铜,萃取率可达98.96%。并对不同酸性介质中铜的萃取率进行了比较,发现在硫酸介质中铜的萃取率相对较高。用4 mol.L-1硫酸反萃负载铜有机相,单级反萃率可达86%以上。初步探讨了其萃取机制,用等摩尔系列法确定萃合物的组成为CuR2。     

SiO2浓度对Zr-4合金包壳管力学和腐蚀性能的影响

Zr-4合金包壳管在核工业中应用广泛,为探究一回路水质环境中SiO2的浓度对Zr-4合金组织性能的影响,利用高温高压反应釜模拟锆管在反应堆一回路的工作环境来开展实验.以显微硬度值和腐蚀失重值为指标,研究了锆管在不同SiO2浓度下的力学性能和腐蚀性能.结果表明,随着SiO2浓度的增加,Zr-4合金的显微硬度值逐渐提高,但在腐蚀介质环境中的耐腐蚀性能明显降低.     

沉淀硬化不锈钢耐蚀抗磨性能的研究

用失重法测定了沉淀硬化不锈钢17-4PH在硫酸、石英砂固液两相介质中的腐蚀磨损速率,研究了介质浓度、冲刷速度和冲刷时间对17-4PH耐蚀抗磨性能的影响规律.试验结果表明,介质浓度越高、冲刷速度越大,17-4PH腐蚀磨损失重越大;而随着冲刷时间间隔的延长,腐蚀磨损失重越小.     

阴离子介质对WC-10Co合金电化学腐蚀行为的影响

研究了WC-10Co合金在浓度分别为0.05 mol/L和0.1 mol/L的Na Cl、Na NO3以及Na2SO4等3种阴离子介质中的电化学腐蚀行为。采用电化学阻抗谱(EIS)和动电位极化曲线2种方法研究合金的电化学腐蚀行为,通过传质电阻R和自腐蚀电流密度Icorr2个动力学参数对阴离子介质及其浓度对合金的腐蚀性进行比较。通过合金腐蚀表面扫描电镜观察,结合合金在3种介质中EIS对应的等效电路图对腐蚀机理进行分析。结果表明,Na NO3介质对合金的腐蚀性最弱,Na2SO4介质对合金的腐蚀性最强;3种介质对合金的腐蚀性随其浓度增加而增强;合金在Na2SO4介质中的腐蚀机理较在其他2种介质中相对复杂。     

稀土对铝和铝合金耐腐蚀性能影响的研究

一、前言用动电位扫描法,测量添加稀土的铝和铝合金在不同介质中的击穿电位研究及其腐蚀性能。研究了添加稀土元素对铝锰和铝镁两种合金体系的小孔腐蚀,均匀腐蚀和大气腐蚀性能的影响。两类不同材料分别在四种不同介质中的腐蚀实验结果表明:添加适量     

烧结Nd-Fe-B磁体腐蚀动力学行为

研究了不同成分的烧结Nd-Fe-B磁体在恒定湿热和中性盐雾腐蚀环境中的腐蚀动力学行为,讨论了不同合金成分和腐蚀条件对磁体腐蚀速率的影响,探讨了烧结Nd-Fe-B磁体在不同介质中的电化学行为.结果表明:烧结Nd-Fe-B磁体在湿热环境中的重量变化表现出明显的抛物线衰减规律,而在盐雾腐蚀环境中的重量变化表现出先增后减的规律.以重稀土Dy替代少量Nd,并添加少量Co等元素,可以提高烧结Nd-Fe-B磁体的耐湿热和耐盐雾腐蚀性能.     

管线钢管焊接接头腐蚀环境失效与安全评价研究现状

在酸性腐蚀介质环境服役的钢管,腐蚀介质与力学载荷耦合后将加速焊接接头失效.介绍了管线钢管焊接接头在酸性腐蚀介质环境下的失效模式,主要包括应力腐蚀开裂、氢致开裂以及考虑裂纹尖端H+扩散聚集的腐蚀断裂与腐蚀疲劳,并介绍了在酸性腐蚀介质环境服役管线管接头工程临界评估(ECA)的常规处理技术,以期能为今后该领域技术的发展提供参考.     

Q235钢在实际土壤与模拟溶液中的腐蚀行为

对比分析了Q235钢在实际土壤和模拟溶液中的腐蚀行为,计算了其腐蚀失重,利用SEM和XRD方法分析了两种腐蚀介质中Q235钢的锈层形貌、物相结构及相对含量,并分析了不同介质中材料的极化曲线。结果表明:Q235钢在两种不同腐蚀介质中的腐蚀行为存在较大差异。Q235钢在模拟溶液中的腐蚀速率远高于实际土壤,至周期360h达到0.413mm/a,约为实际土壤的4.5倍;Q235钢在实际土壤中呈蚀斑相连长大扩展的腐蚀形貌,其腐蚀产物为α-FeOOH、γ-FeOOH、Fe3O4和Fe2O3;模拟溶液中试样为均匀腐蚀形貌,阴极过程主要受析氢控制;随腐蚀周期的延长,内锈层中生成结晶性良好的Fe3O4,降低了试样的腐蚀速率。     

超高强船体钢EH890在不同pH海洋环境中的耐蚀性研究

为研究超高强船体钢EH890在不同酸碱度海洋环境中的耐蚀性,分别在pH3,pH7,pH11的3.5％NaCl溶液中进行了电化学腐蚀实验,用场发射扫描电镜分析了在不同溶液中浸泡24 h后腐蚀形貌,并结合X射线光电子能谱研究了腐蚀产物组成,对比分析了EH890钢在不同pH海洋环境中的腐蚀行为.结果表明,在pH3的3.5％N...     

纯锆R60702板材焊接接头的腐蚀性能研究

采用挂片失重法,研究了工业纯锆R60702板材钨极氩弧焊焊接接头分别在沸腾条件下的10%,30%,70%(质量分数)浓度的硫酸和醋酸+2%KI+200 mg·kg-1Na Cl介质中的腐蚀性能,并分析了接头腐蚀后的表面形貌及腐蚀机制。实验结果表明,在相同浓度硫酸介质中,焊接接头的腐蚀速率均比母材腐蚀速率大;当硫酸腐蚀液浓度低于30%(包含30%)时,母材和焊接接头均具有优异的腐蚀性能;当硫酸腐蚀液浓度高于30%时,母材和焊接接头腐蚀速率显著增大,硫酸浓度对母材和焊接接头的腐蚀速率影响均较大;在相同浓度醋酸+2%KI+200 mg·kg-1Na Cl混合介质中,接头的腐蚀速率均比母材腐蚀速率小;当醋酸浓度小于70%时,浓度对母材和接头的腐蚀性能影响较小,这是因为焊缝区域的粗大组织降低了Cl-和I-吸附晶界引起的氧化膜局部破坏效应;工业纯锆R60702母材和焊接接头在硫酸介质中腐蚀方式均为全面腐蚀,在醋酸+2%KI+200 mg·kg-1Na Cl混合介质中的腐蚀方式为点蚀。     

Stress corrosion cracking in high strength steel under mode III loading

Stress corrosion cracking (SCC) of high-strength steel in aqueous environment and hydrogen induced cracking (HIC) during dynamic charging under Mode III loading were investigated. The threshold stress intensities for SCC and HIC under Modes III and I were measured and compared. It was found that both SCC and HIC under Mode III loading initiated and propagated on the planes inclined at 45 deg to the notch plane, differing from that under Mode I loading. The fracture surfaces, however, revealed intergranular facets, similar to that under Mode I loading. The addition of thiourea decreased the threshold value for SCC under Mode III and Mode I loading, which was still higher than that for dynamic charging. The threshold values of both SCC and HIC under Mode III were larger than that under Mode I,i.e., K_IIIH> K_IH, K_IIISCC > K_ISCC. Based upon the fracture mechanics analysis, this difference is attributed to the different equilibrium hydrogen concentration between Modes III and I loading. These results give strong evidence that the SCC mechanism in high strength steel under Mode III loading is also related to hydrogen induced cracking. Formerly Student at Beijing University of Iron and Steel     

Heavy plate production: demand on hydrogen control

Abstract

Hydrogen in steels causes various types of cracking, which occur when the amount of hydrogen in a steel reaches a critical level. This phenomenon results from excessive internal hydrogen pressure, and is associated with the formation of cracks at material imperfections, for example non-metallic inclusions. Consequently, cracking can be prevented either by avoiding an excessive amount of hydrogen or by increasing the critical level for cracking. These two cases are demonstrated from the points of view of steelmaking and plate production. In certain applications, the hydrogen content in a steel may be increased by the absorption and diffusion of atomic hydrogen produced on the metal surface by a corrosion reaction, for example in a wet H₂ S environment. This phenomenon can lead to hydrogen induced cracking (HIC). The damage mechanism as well as the main strategy to prevent hydrogen induced cracking is described in detail.     

Ti35合金焊接接头在高温硝酸中的腐蚀性能研究

以沸腾的核乏燃料后处理模拟料液及空白硝酸溶液为腐蚀液,研究了Ti35合金焊接接头的耐腐蚀性能。在模拟料液中对Ti35合金熔敷金属及焊接热模拟样进行全浸腐蚀实验,间接评价了焊接接头熔区及热影响区的耐腐蚀性能。结果表明:Ti35合金焊接接头在沸腾空白硝酸溶液及模拟料液中均具有良好的均匀腐蚀性能,焊缝熔区及热影响区的腐蚀速率大于焊接接头的腐蚀速率,焊接接头的腐蚀对焊接应力的敏感性不高;在沸腾空白硝酸介质中,硝酸浓度对焊接接头的耐蚀性能有较大的影响,随硝酸浓度的提高,焊接接头的耐蚀性能有所下降;硝酸溶液中氧化性金属阳离子对Ti35合金的焊接接头具有缓蚀作用。     

管线管氢致开裂试样检测及分析

对管线管氢致开裂(HIC)试验后试样进行超声波探伤和金相分析。结果表明:HIC试验后未发现氢致裂纹缺陷,但超声波探伤可检测到大型B类夹杂物及表面氢鼓泡。本试验所取试样较大B类夹杂物出现在管体壁厚中心与外壁之间,可以大致推断较大B类夹杂位于原始铸坯1/2半径到表层细晶区之间,其成因与铸坯芯部成分偏析无关。氢鼓泡中有大颗粒状氧化镁及硫化钙夹杂,其余区域为铝酸钙夹杂,故夹杂物是形成氢鼓泡的诱因之一。     

铁素体晶界结构对管线钢HIC敏感性的影响

摘要：铁素体作为酸性环境用管线钢的主要组织类型之一,探究其晶界结构与管线钢氢致开裂（HIC）敏感性之间关系,可为进一步优化管线钢的抗HIC性能提供指导。对热轧态管线钢进行不同工艺热处理,采用扫描电子显微镜（SEM）、电子背散射衍射（EBSD）、透射电子显微镜（TEM）观察了试样的晶界、位错结构及氢鼓泡、氢致裂纹形貌,用电化学充氢及动态充氢方法对试样的HIC敏感性及氢致塑性损失进行了测试,用电化学氢渗透及氢微印实验对试样的氢捕获效率及氢原子分布进行了观察与分析,探索了铁素体晶界结构与HIC敏感性之间内在关联。其结果表明：当材料中以小角度晶界占主导或大小角度晶界比例约为1∶1时,对氢原子的捕获效率较高,HIC敏感性也相对较大;大小角度晶界均能捕获氢原子,但与氢的作用机制不同,大角度晶界主要促进氢致裂纹萌生,而小角度晶界主要促进氢致裂纹扩展。     

夹杂物对16MnR（HIC）抗氢致裂纹的影响

对不同硫含量的１６ＭｎＲ（ＨＩＣ）中厚板进行ＨＩＣ试验及夹杂物分析,结果表明,１６ＭｎＲ（ＨＩＣ） 氢致裂纹敏感性随Ｓ含量增加而增强,硫化物夹杂达到２．０级仅出现氢鼓泡,大于２．０开始出现氢致裂纹以及氢鼓泡,小于０．５级抗氢致裂纹性能优良。     

Influence of bulk and grain boundary phosphorus content on hydrogen induced cracking in low strength steels

The influence of bulk and grain boundary phosphorus content in carbon-manganese-steels was studied by constant extension rate test method in 1 m H₂SO₄ solution under cathodic polarisation. The hydrogen activity and uptake in the samples was measured using the electrochemical permeation technique. The susceptibility towards hydrogen induced cracking (HIC) increased with phosphorus content, the steel containing lower manganese was found to be more susceptible to HIC. The mode of cracking was mostly transgranular. The effect of phosphorus is related to the bulk content and not to the grain boundary concentration. The susceptibility towards HIC is directly related to the hydrogen uptake which increases with the phosphorus content and decreases with the manganese content of the steels.     

舞钢湿硫化氢环境用低合金高强度钢

湿H2S环境下引起压力容器及管道的腐蚀、氢致开裂（HIC）、H2S应力腐蚀开裂（SSCC）是当前采油、炼油、化工、煤气生产中最为突出的腐蚀问题和技术难题之一。为此，舞钢对防止压力容器与管道在湿硫化氢环境中的开裂问题进行了广泛、深入的研究，相继成功地开发了一系列不同强度级别的湿硫化氢环境用抗硫化氢腐蚀用钢，具有碳当量低、力学性能（尤其是低温冲击韧性）优良、抗氢致开裂性能和抗硫化物应力腐蚀性能良好的特点，钢板的力学性能、抗氢致开裂性能及抗硫化物应力腐蚀性能均达到了国际先进或领先水平。本文还指出了抗湿硫化氢用钢的生产开发方向并提出了质量改进措施。     

Corrosion fatigue crack growth behavior of a squeeze-cast Al-Si-Mg-Cu alloy with different precrack histories

Fatigue experiments have been performed on a squeeze-cast Al-Si-Mg-Cu alloy as a function of precrack history. The precracked conditions were that the compact tension specimen was precracked with a relatively long through-thickness crack (about 6 mm) in air, in aqueous 3 pct NaCl solution, and in air followed by hydrogen precharging. It was found that a relatively long through-thickness crack can grow more rapidly than would be predicted by a traditional ΔK involving three stages under either a corrosion fatigue test after precracking in air or a hydrogen precharging experiment followed by fatigue testing in air. The experimental evidence confirms that a hydrogen-assisted damage mechanism is mainly responsible for the rapid growth phenomenon of a relatively long crack in a corrosive environment compared to the result of fatigue testing in air after hydrogen precharging. The amount of hydrogen production in chemical-microstructure interaction processes in a corrosion fatigue experiment and the effectiveness of hydrogen transport to the region ahead of the crack tip determine the degree of hydrogen-assisted fatigue crack growth, which is controlled by the microstructure of the alloy and the chemical attack on a sharp and fresh crack tip.     

Cracking simulation for strained linepipes exposed to different heavy corrosion and pulsating load

Susceptibility of steel to cracking ‐either by contact with gas in wet H₂S environments or near neutral solutions‐ is a dominant factor for residual life of gas‐line pipes. Three different phenomena are concerned with cracking, namely hydrogen induced cracking (HIC), sulphide stress cracking (SSC) and stress orientated hydrogen induced cracking (SOHIC). Whereas laboratory test methods for HIC are established the situation is different in combination with stress. If the coating is damaged and a near neutral liquid medium is penetrating the pipe surface a strain induced crack might occur. This type of corrosion is named near neutral SCC (NNSCC). A qualified test method with simulated cyclic loading conditions was not available. A test stand including pulsating tension on a high level qualified for high strength steels, wet environments with pH‐values between 2.7 (sour gas) and 8,3 (synthetic seawater) and bubbling several gases such as H₂S, CO₂ or N₂ through the test solution with controlled room temperature was developed. The test‐method enables to qualify steels and pipes for line pipes in tests of short duration compared to lifecycles of line pipes.