接触网零部件应力腐蚀断裂分析

随着铜合金、铝合金、不锈钢材料零部件在接触网中的大规模应用,由于应力腐蚀原因造成零部件失效而影响行车的情况时有发生。为此,对接触网零部件应力腐蚀断裂的机理特征、发生条件、检测方法和防护措施开展研究,为接触网零部件应力腐蚀断裂的判断、分析及预防提供依据。     

长呼输气管线的外防腐设计

在天然气长输管线的设计中，外腐蚀设计是至关重要的，它直接关系到长输管线的运行寿命。在长呼天然气输气管线设计中，根据管线的具体情况，进行经济、技术的比选，选用了煤焦油瓷漆作为管线的主要外防腐层。煤焦油瓷漆防腐性能好、价格合理，材料来源广泛，涂层厚，适用于螺旋焊缝管，电绝缘性好，吸水性低，使用寿命超过50a．全线共设置10座阴极保护站，采用“阴极保护参数在线自动监测系统”对管道的阴极保护参数进行在线监测。     

埋地输油管道外防腐层的检测与评估

运用RD-PCM地探仪对某机场埋地输油管道的外防腐层进行不开挖检测,检测外防腐层老化程度,确定外防腐层的破损处(露铁点)。检测管道外环境土壤的腐蚀情况,确定土壤的腐蚀等级。对露铁点选择性开挖,了解露铁点的现状。分析牺牲阳极的保护情况,计算确定牺牲阳极的保护年限。对该输油管道的现状进行系统评估,确保管道在设计年限内可靠运行。     

涂层与阴极保护下的管道外腐蚀研究与控制

长期以来 ,一直认为管道在涂层和阴极保护协同保护下不会产生外壁腐蚀或腐蚀轻微。应用第三代高精度智能清管检测器对榕山—佛荫长为 2 5 4km的管线进行检测 ,发现了 455处外壁腐蚀 ,研究结果表明 :管道建设时 ,涂层施工的质量较差 ;使用维护过程中涂层材料老化严重、失修 ;管线上阴极保护系统长期故障使管道欠保护 ;执行了有严重缺陷的行业标准 ,至今不知管线上监测到的保护电位距真实的极化电位的差距有多大 ;管线的阴极保护度数据难以采集到。针对上述问题提出了控制腐蚀的方法。     

埋地输油管道腐蚀调查及改造设计

针对龙鞍埋地输油管道的腐蚀现状 ,通过检测数据 ,对管线的腐蚀环境、防腐层状况、管体腐蚀等情况进行分析和评价 ,探讨腐蚀原因和机理 ,并提出了管道改造的设计方案 ,对方案的优缺点及经济因素进行了分析和比较     

Time-variant bulk carrier reliability analysis in pure bending intact and damage conditions

Time-variant reliability analysis of a corroded bulk carrier in intact and damage conditions is performed by First-Order (FORM), Second-Order (SORM) Reliability Methods and Importance Sampling simulation. Annual failure probabilities are determined up to 25-year ship lifetime, accounting for time-variant corrosion wastage of structural members contributing to hull girder strength. Statistical properties of hull girder capacity are determined by Monte Carlo simulation, applying three correlation models among corrosion wastages of structural members contributing to hull girder strength, namely no correlation, full correlation and full correlation among wastages of structural members belonging to the same category of compartments. A modified incremental-iterative method is applied, to account for instantaneous neutral axis rotation, in case of asymmetrical damage conditions, as for collision and grounding events. Incidence of intact/damage condition, as well as correlation among corrosion wastages, on annual sagging/hogging time-variant failure probability is investigated and discussed. Time-variant sensitivity analyses for intact and damage conditions are also performed, to investigate the incidence of random variables' uncertainties on the attained failure probability. Finally, the bulk carrier section scheme, benchmarked in the last ISSC Report, is applied as test case.     

Corrosion rate measurements in steel sheet pile walls in a marine environment

Corrosion of steel structures in the marine environment is a major problem. The deterioration of this kind of structures is costly and difficult to predict both when designing new structures and when estimating the remaining service life time for existing structures. The aim of this investigation was to find indicative values for the corrosion rate of steel sheet piles on the Swedish west coast. Such corrosion rates (mm/year) can be used both when designing new structures by oversizing the steel thickness and when estimating the bearing capacity of existing sheet pile structures. Earlier investigations on the corrosion rates along the Swedish east coast – with salinity from about 0.2% to 0.8% – are still used today as guidelines for the corrosion rate of all steel structures in the Swedish maritime environment even though the salinity on the west coast can be as high as 3.0%.Steel sheet pile wharfs located in the port of Halmstad on the Swedish west coast were inspected by ultrasonic measurements. Three wharf structures with a total length of about 700 m were inspected. None of the inspected wharfs had or have had cathodic protection. The thickness measurements of the steel sheet pile structures were performed by divers.The age of the three inspected sheet pile structures ranged from 36 to 51 years. The dimensions of the original sheet pile sections are known. One of the quay structures is located along a river. The salinity at all wharfs varied from low values at the surface to approx. 2% at the bottom (also in the river outflow).The measured average corrosion rates were in the same order as the design values in the European code. However, the results indicate increased corrosion rates about 1 m below the mean water surface and at the level of the propellers from the ships berthing the most frequented of the inspected wharfs, 3–6 m below water surface.The tolerances of steel sheet thicknesses – usually in the order of ±6% – are often neglected when investigating the remaining thickness in steel sheet piles. A simple calculation model shows that the sheet pile must be almost 50 years of age before an accurate estimation on the corrosion rate can be made, considering the tolerances, if the true original sheet pile thickness is not known.     

国产汽车耐腐蚀试验研究

阐述了腐蚀试验在评价汽车设计、环境研究、新产品开发、材料选择及质量控制中的重要作用，介绍了试验规程及其强度，试验前的准备工作包括腐蚀检查，机械检查，车辆拍照，涂层厚度测量，金属厚度识别及油漆层划线等。另外，试验结果评价作了介绍，并对存在的问题提出了改进建议。     

Time-variant ultimate longitudinal strength of corroded bulk carriers

Many bulk carrier losses have been reported of late, and one of the possible causes of such casualties is thought to be the structural failure of aging hulls in rough weather. In aging ships, corrosion and fatigue cracks are the two most important factors affecting structural safety and integrity. This paper uses a set of the time-dependent corrosion wastage models for 23 different member locations/categories of bulk carriers previously developed by the authors, based on the available corrosion measurements for existing large bulk carrier structures. Differences due to the location and corrosion severity of every member type are taken into account. The nominal design corrosion values for the primary members are suggested based on the annualized corrosion rates obtained in the present study. The effect of time-variant corrosion wastage on the ultimate hull girder strength as well as the section moduli is studied. The criteria for repair and maintenance of heavily corroded structural members so as to keep the ultimate longitudinal strength at an acceptable level are discussed. Important insights and conclusions developed are summarized.     

船用新型高强耐蚀铸造铝合金ZL305A研究

本文介绍研制的新型铸造铝合金ZL305A是一种强度高，时效稳定性好，耐蚀性优良的船用新材料。系统地研究了ZL305A合金的化学成分、力学性能、热处理工艺、时效稳定性和耐腐蚀性能。该合金的研制成功，为船用材料开拓了新的应用领域。