浅谈杂散电流腐蚀机理及防护措施

详细阐述了地铁杂散电流的形成机理及主要的防护措施。     

Effect of pitting corrosion on local strength of hold frames of bulk carriers (2nd Report)—Lateral-distortional buckling and local face buckling

Pitting corrosion is typical corrosion observed on coated hold frames of bulk carriers which exclusively carry coal and iron ore. In order to secure the safety of these types of bulk carriers, it is important to understand the effect of pitting corrosion on local strength of hold frames.

In order to investigate this effect, a series of 4- and 3-point bend tests on structural models which consist of web, shell and face plates has been carried out. Artificial pitting was created on the web plate to simulate pitting. In the 4-point bend tests, two equal concentrated loads have been applied vertically at the one-third points of simply supported models so that compression load due to bending would act on the face plate. In this testing condition, lateral-distortional buckling occurred before reaching the ultimate strength and local buckling of the face plate was observed after reaching the ultimate strength. The effect of web plate pitting on the lateral-distortional buckling strength was found to be small but the ultimate strength decreases with increase in the degree of pitting intensity. In the 3-point bend tests, concentrated load has been applied vertically at the center of simply supported models so that compression load due to bending would act on the face plate. In this testing condition, local face buckling occurred just after reaching the ultimate strength. The ultimate strength is found to be decreasing with increase in the degree of pitting intensity.

A series of non-linear FE analyses has been performed to simulate the deformation behavior observed in the tests. It has been revealed that even in the case of randomly distributed pitting corrosion the ultimate strength of the structural models was almost the same as that of the structural models with uniform corrosion corresponding to the average thickness loss.     

水冷型艉轴的腐蚀形态及防护措施

艉轴是船舶的重要部件,其性能的好坏直接影响船舶动力装置性能的发挥和船舶的安全性,而腐蚀又是直接危害艉轴性能的主要因素。文章归纳了艉轴腐蚀易发生的部位及腐蚀形态,通过分析其腐蚀机理,提出了有效的防护措施。     

钢筋混凝土结构的腐蚀及防护措施

介绍钢筋砼结构防腐蚀的重要性,根据钢筋砼结构的特定使用环境,提出钢筋砼在结构设计、施工等各阶段合理地应用各种防腐蚀保护措施。     

船舶结构钢海洋环境点蚀模型研究之二:实船蚀坑形态与径深比时变模型

文章基于点蚀生长原理与实船蚀坑形态检测数据,对船舶受点蚀构件的两类主要蚀坑的形态、形成机制及其随船龄演化情况作了大致描述.认为遭受点蚀船舶构件的蚀坑形态与其所处位置、服役时间等密切相关;两类蚀坑形态差异的原因在于其各自点蚀进程中的具体控制因素及相应的影响程度存在较大区别.论述证明将点蚀蚀坑径深比处理成随时间变化的函数是有理论和事实依据的;并与点蚀深度模型相结合,依据Yamamoto实测散货船货舱区肋骨蚀坑数据建立了相应的蚀坑径深比时变模型.     

地铁杂散电流的腐蚀及防护影响分析

根据轨道交通的杂散电流产生原理,结合工程实际,提出了杂散电流防护体系;并结合轨道交通的工程特点,从杂散电流与接地的关系分析,提出了隧道和车站的结构钢筋可用作设备接地的建议.     

关于主轴颈与主轴承电化腐蚀的产生及防范

主要分析并介绍了船用主柴油机轴系产生电化腐蚀的原因和防范措施。     

船体结构总纵极限强度的简化逐步破坏分析方法

本文基于Smith方法,应用梁-柱理论、理想弹塑性假设、平截面假设和塑性铰理论建立了加筋板单元的应力-应变关系曲线,导出了船体结构总纵极限强度的简化逐步破坏分析方法并编制成FORTRAN计算程序.应用作者导出的简化逐步破坏分析方法分析计算了Reckling 23号模型总纵极限强度.计算结果表明,本文导出的简化逐步破坏分析方法和计算程序正确可靠,可供船体结构设计和使用.本文还对船体结构总纵极限强度的影响因素进行了分析,其中包括加筋板单元的载荷-缩短行为、横向压力、材料屈服强度和腐蚀等.     

稀土对锌电极在碱性溶液中耐蚀性能的影响

本文通过动力学参数测试,析气实验研究了添加稀土金属对锌电极在碱性溶液中耐蚀性能的影响,结果表明添加少量稀土元素可以显著提高锌电极在碱性溶液中的耐蚀性.     

新型国产不锈钢材料在汽车排气系统中的应用

对汽车排气系统及其主要零件的腐蚀问题进行了分析,包括腐蚀坑深度与冷凝液pH值、Cl-、SO24-离子浓度的关系,并主要介绍了一种新型国产不锈钢409材料在汽车排气系统的应用。结果表明：该材料具有耐腐蚀性能良好、低成本的优点。