Erosion and Corrosion of Mild Steel and Stainless Steel in Sodium Carbonate／Bicarbonate Solution Bearing Alumina Particle

With a rotating cylinder electrode apparatus, the polarization behaviors of the mildsteel and the stainless steel 0Crl8Ni9 in NaHCO3 (0.5M) NazCO3 (0.5M) solution with andwithout erodent particles were investigated and compared. The results show that the rotationspeed of cylinder hardly affects the polarization behavior of sample in solution without particlesbut exerts a great influence on that with particles. Increasing rotation speed, the free corrosionpotential shifts to positive direction and the oxygen limiting current density increases. Both themild steel and stainless steel 0Crl8Ni9 experience a significant increase of the mass loss by in-creasing erosion, and erosive wear was dominated by severe micro-plowing. The insufficientmechanical strength of both materials leads to a low resistance to particle removal. Increasingperipheral velocities of the rotating cylinder enhances the corrosion rate of the mild steel. Thestainless steel 0Crl8Ni9, due to a high erosive wear, also suffers from similar erosion-corrosiondamage, despite that its corrosion resistance is much higher than that of the mild steel.     

Corrosion Behavior of Nitrogen Containing Hot Rolled 304LN in Nitric Acid Medium

The corrosion behaviour of 304LN stainless steels containing three different nitrogen content (0.132, 0.193, 0.406 wt% N) was investigated by potentiodynamic anodic polarization technique, in 1, 4, 6 M nitric acid and simulated high level waste (HLW) medium. The results showed that all three alloys exhibited good corrosion resistance in nitric acid and simulated HLW and the corrosion properties were found to be similar. Owing to the spontaneous formation of the protective chromium oxide passive film in nitric acid and simulated HLW, increasing the nitrogen content of the alloy did not indicate any discernable effect on the corrosion resistance in both media. It was also found that the oxidizing ions present in simulated HLW did not deteriorate the passive film stability of the nitrogen containing alloys. In chloride medium, the highest nitrogen content 304LN stainless steel showed a profound increase in pitting corrosion resistance when compared to the lower nitrogen content alloy. Optical and scanning electron microscopy was carried out to obtain information about the microstructure. The results of the investigation are discussed in the paper.     

激光熔敷Ni60／WC合金层的腐蚀磨损特性

研究了４５钢表面激光熔敷镍基ＷＣ合金层的耐蚀性及在不同冲击速度和不同浓度酸性介质下的腐蚀磨损特性。结果表明，激光熔敷Ｎｉ６０／ＷＣ合金层不论耐蚀性还是抗腐蚀磨损性能同于２Ｃｒ１３不锈钢。应用微机对试验结果进行逐步回归分析，得出了影响因素与腐蚀磨损速度的害量关系，并探讨了熔敷层的腐蚀磨损过程。     

新型双相铸造不锈钢的组织及其磨蚀行为研究

研究了新型双相铸造不锈钢的化学成分、组织及其腐蚀与磨蚀行为。结果表明,该钢在含有固相颗粒的高温碱介质中具有良好的耐腐蚀与耐磨蚀性能。此外,还具有较好的力学性能和铸造性能,而且成本较低,具有广阔的工业应用前景     

不锈钢在高温高压釜乙酸溶液中耐腐蚀性能研究

在试验室中模拟不锈钢所处的高温高压生产环境,对两种牌号不锈钢在同种乙酸介质中的耐腐蚀性能进行对比实验研究,并且对同种不锈钢试样在不同方法制备的乙酸介质中的耐腐蚀性能进行对比研究。试验结果显示,送样316L不锈钢的耐腐蚀性能较00Cr17Ni14Mo2不锈钢的耐腐蚀性能差;316L不锈钢在乙醇制乙酸中的耐腐蚀性能低于在乙烯制乙酸中的耐腐蚀性能。上述试验为某化工厂生产设备的选材以及生产介质的选择提供了相应依据和参考。     

新型汽车排气系统用铁素体不锈钢的冷凝液腐蚀研究

 铁素体不锈钢中Cr元素对其耐腐蚀性能起着非常重要的作用。本文采用实验室冷凝液腐蚀实验方法,对一系列汽车排气系统用铁素体不锈钢在实验室模拟冷凝液中的腐蚀性能进行了研究。所有钢种经过10周期的实验室冷凝液腐蚀实验后,研究结果表明：Cr当量高于17%的铁素体不锈钢与含17%Cr的铁素体不锈钢耐实验室冷凝液腐蚀性能相当,且平均腐蚀失重量均小于6g/m2,平均最大腐蚀深度均小于0.03mm。在此实验结果的基础上,对新开发的439M型铁素体不锈钢和409L型铁素体不锈钢进一步开展5周期、10周期、20周期的实验室冷凝液腐蚀实验,并使用极值分析方法对三种周期冷凝液腐蚀实验后样品的最大点蚀深度进行统计分析,研究结果表明,新开发的439M型铁素体不锈钢的预测寿命是409L的1.6倍。     

Mn对2205双相不锈钢耐点蚀性能的影响

研究锰元素对2205双相不锈钢耐点蚀性能的影响, 锰质量分数的变化范围为0. 93%~1. 26%.分别采用化学腐蚀法、动电位极化法研究双相不锈钢2205的耐腐蚀性能, 采用夹杂物自动分析技术研究锰对钢中夹杂物种类及数量的影响, 通过扫描电镜、能谱及夹杂物原位分析法观察化学腐蚀及电化学腐蚀前后钢中夹杂物及其周围钢基体的变化情况.采用电感耦合等离子体发光光谱测定腐蚀产物的成分.研究结果表明, 不同类型的夹杂物对耐腐蚀性能的影响不同, (Mn、Si) 氧化物以及(Mn、Si、Cr) 氧硫化物在腐蚀液中更易溶解进而促进腐蚀, 而(Cr、Mn、Al) 氧化物却很稳定.锰的加入会促进钢中(Cr、Mn、Al) 夹杂的析出, 此类夹杂物不仅自身很容易被含Cl离子的溶液腐蚀, 而且作为点蚀的起始点, 促进了点蚀坑的形成, 加快了基体腐蚀, 最终导致不锈钢耐点蚀性能的下降.      

Corrosion Performance of High Strength 15Cr Martensitic Stainless Steel in Severe Environments

High pressure and high temperature corrosion performance of high strength 15 Cr martensitic stainless steel was studied in different severe environments—live acid(10%HCl+1.5%HF+3%HAc+5.1% corrosion inhibitor),spent acid and formation water containing CO2.The results show that the corrosion of high strength 15 Cr martensitic stainless steel in live acid is most serious,and the uniform corrosion rate is far greater than those in spent acid and formation water containing CO2 corrosion environments,but all of them can be acceptable for oilfield.Acidizing corrosion inhibitor displays a good matching ability with the high strength 15 Cr martensitic stainless steel in terms of decreasing the uniform corrosion rate,which changes mainly the anodic process of high strength 15 Cr martensitic stainless steel.The corrosion potential moves to the positive direction,thus the corrosion current density decreases significantly.There are some different degrees of pitting of high strength 15 Cr martensitic stainless steel after corrosion tests in live acid,spent acid and formation water containing CO2,and the pitting density aggravates significantly and the maximum pit depth decreases in the corrosion sequence.     

高温不锈渗碳轴承钢的研发现状与进展

 航空用轴承钢向耐高温、耐腐蚀、高承载、长寿命方向发展,现役的M50轴承钢存在强度高但韧性和耐蚀性不足的问题;M50 NiL渗碳轴承钢虽然通过降低碳含量和调整合金成分来提高韧性,但仍越来越无法满足高推重比的航空发动机的发展需求,并且耐蚀性不足问题也未解决。高铬不锈轴承钢BG-42和高氮Cronidur30轴承钢虽然抗腐蚀能力好,但是表面硬度和心部韧性仍不足。以CSS-42L钢为代表的高温不锈渗碳轴承钢拥有高强韧性和优良耐蚀性能,不仅在航空轴承应用上极具竞争优势,而且也可应用于在高温或腐蚀性环境下使用的齿轮、轴和紧固件等,但是国内外相关研究工作仍不足且缺乏系统性,因此对其研发现状进行综述和总结尤为重要。从航空用高温轴承钢发展历程出发,详细介绍了国内外高温不锈渗碳轴承钢的研发背景和合金成分设计思路;综述了铬、钴、钼、镍、钒、钨等主要合金元素对组织和性能影响规律,其中钴的加入虽然不直接参与析出强化,但能够起到抑制δ-铁素体形成和促进弥散析出的特殊作用;分别从表面渗碳和心部材料两个方面,揭示了调控热处理工艺对微观组织和强韧性的影响规律。在此基础上,针对国内外高温不锈渗碳轴承钢基础理论和制造工艺研究的不足,提出了优化合金成分、突破渗碳热处理技术,以及加强不同工况下组织演变、疲劳损伤和破坏机理研究的研发方向。     

304不锈钢表面冷喷涂TC4钛合金涂层性能研究

采用冷喷涂技术在304不锈钢表面制备了TC4钛合金涂层,通过扫描电子显微镜观察了涂层的形貌、组织结构,并利用电化学方法研究了涂层的腐蚀电化学特征。研究结果表明,冷喷涂制备的TC4钛合金涂层致密性存在较为明显的梯度现象,靠近基体的涂层密度明显高于表面;涂层喷涂过程没有出现明显氧化现象,与基体的结合强度可达20 MPa左右;涂层的耐腐蚀性能优于304不锈钢,可大大提升不锈钢材料在海洋环境中的耐点蚀性能。