膨胀节腐蚀形貌宏观分析研究

介绍了利用肉眼或借助于放大镜所具备的大景深,能够快速地检验一个很大的区域,而且还可以观察到失效部件的颜色和结构的微妙变化[1].对炼油厂催化裂化装置中失效的0Cr17Ni12Mo2不锈钢膨胀节所具有的腐蚀产物与沉淀物的颜色、形状和形貌特征及其微妙变化进行分析,总结出了四种典型的点腐蚀形貌特征与四种典型的腐蚀开裂形貌特征,从而可快速判断其腐蚀形态.     

烟气腐蚀油套管物膜试验研究

通过模拟稠油热采技术中的水蒸气环境进行腐蚀试验,研究N80油井管用钢的腐蚀形态以及腐蚀速率,确定表面主要腐蚀产物的成分,为油田选材及腐蚀防护提供依据.结果表明:在160℃,腐蚀速率为0.1655mm/a,参照NACE RP-0775-91标准对平均腐蚀的规定,达到严重腐蚀程度.腐蚀产物是Fe3O4和Fe2O3的混合物.     

人工神经网络在腐蚀与防护领域的应用

介绍了人工神经网络的概念、分类、组成,概括了腐蚀实验数据的特点,即数据量大,来源广泛,存在大量随机数据,由于人工神经网络是一个非线性动力学系统,所以可以轻易地实现函数逼近,数据聚类、模式分类,优化计算等功能,因此是处理腐蚀实验数据的一个有力手段,。人工神经网络迄今为止,已在区分腐蚀类型,确定主要腐蚀因子,解析谱图数据,腐蚀监测,腐蚀预测等方面有了较成功的应用,分析了人工神经网络技术在腐蚀防护领域的应用前景。     

油水集输管线中沟槽腐蚀成因分析

油水集输管线中因沟槽腐蚀所造成的破坏,带来了巨大的经济损失。作者从介质的组成、相组成、流动特性和材质等方面,对沟槽腐蚀的成因进行了讨论分析。     

污损生物引起金属局部腐蚀的原因

海水／金属界面间会同时产生金属腐蚀与生物附着。两者的相互作用导致金属腐蚀破坏。对实际海上平台和舰船的调查表明，污损生物对平台等海上金属构筑物可产生不同形式和不同程度的腐蚀破坏，即使在阴极保护下，也是如此。下面仅从污损生物本身分析其原因。１裸体金属由于...     

我国大气腐蚀网站试验研究回顾及发展建议

回顾了４０多年来我国大气腐蚀试验研究的概况,着重介绍了“六五”以来研究取得的主要进展,根据国家需要与研究现状,结合国外研究动态提出了今后的展望与发展建议。     

腐蚀环境对预腐蚀铝合金腐蚀疲劳性能的影响

采用不同环境下的轴向加载疲劳性能测试方法,研究了不同环境对预腐蚀7XXX铝合金腐蚀疲劳性能的影响.结果表明:腐蚀环境对其疲劳寿命的影响从重到轻依次是:油箱积水、盐水、潮湿空气和实验室空气.当应力比R为0.5和0.06时,潮湿空气下的疲劳寿命比实验室空气下的略低,降低的幅度随着应力的降低而增大;在低应力水平区盐水和油箱积水环境对疲劳寿命的影响基本相同.当应力比R为-1时,盐水下的疲劳寿命总是略低于油箱积水环境下的疲劳寿命;潮湿空气相比实验室空气下的疲劳寿命随着应力的降低,降低的幅度比应力比为0.5和0.06时要略大.     

硫化物应力腐蚀裂开时硫化氢极限浓度的研究

用慢应变速率应力腐蚀试验机研究了含硫天然气输气管道用钢在5%氯化钠溶液中的硫化物应力腐蚀裂开(SSCC) 敏感性与硫化氢浓度之间的关系.本文报导了20号钢和16锰钢在上述介质中发生SSCC的硫化氢极限浓度,为工程设计和生产过程的安全保障提供了重要的参数.     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。