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本文对寄生回路进行了一些分析研究,特别是对目前广泛使用的典型机床控制电路进行了分析,对其中寄生回路产生故障的原因进行了分析,并且提出改进措施。 相似文献
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《机械制造文摘:焊接分册》2010,(1):10-10
碳对高强度奥氏体焊条熔敷金属冲击韧性的影响
对系列碳含量的高强度奥氏体焊条熔敷金属冲击韧性进行了试验,采用扫描电子显微镜对冲击断口和金相磨面的微观形貌进行了分析,结合X射线能谱仪和透射电子显微镜对其中第二相的成分和结构进行了确定,并采用热力学软件Thermo-Calc对凝固相的组成及其中第二相的含量进行了计算。 相似文献
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目的研究哈氏合金C-276在溴胶溶液中的耐蚀性能,分析哈氏合金C-276在溴胶溶液中的腐蚀及失效机理。方法采用挂片试验方法,模拟溴化丁基橡胶生产过程中溴胶混合釜的腐蚀环境,研究温度、液溴含量、水含量、转速等环境因素影响哈氏合金C-276的腐蚀规律,利用SEM、XRD等现代分析技术,对腐蚀产物形貌、成分进行分析。结果哈氏合金C-276在含溴腐蚀溶液中的主要腐蚀产物为Ni Br2、Fe Br2、Mo Br2、Cr Br3等,腐蚀速率随温度、水含量、液溴含量以及转速的增加而增大。温度、水、液溴以及转速等因素均对腐蚀的发生起到了重要作用,腐蚀类型以全面腐蚀为主,伴随晶间腐蚀。结论溴胶混合液腐蚀环境下,哈氏合金C-276发生了严重的电化学腐蚀,提高温度、液溴含量、水含量、转速均会明显增加哈氏合金C-276的腐蚀速率。哈氏合金C-276不能作为溴化丁基橡胶生产设备中溴胶混合器的主材质。 相似文献
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目的提高多相流动状态下温度对X70钢CO2腐蚀机理的认识。方法采用自制实验装置和挂片实验,模拟起伏管路段塞流动条件下X70钢的CO2腐蚀状态,通过电子显微镜和电化学在线监测等手段对试样表面形貌、腐蚀速率以及在线腐蚀情况进行观察和分析,侧重研究多相流动状态下温度对X70钢CO2腐蚀速率的影响。结果当温度达到90~98℃时,由于腐蚀产物膜的影响,CO2分压对腐蚀速度影响甚微,腐蚀速度降至较低水平。当温度在60~80℃之间时,腐蚀挂片表面的腐蚀状态不稳定,出现局部腐蚀或均匀腐蚀,当CO2分压较低时(如0.15 MPa),易形成均匀腐蚀;当CO2分压较高时(如0.6 MPa),易形成局部腐蚀。当温度在40~80℃之间时,随着CO2分压的增加,腐蚀速率达到最高值的温度越来越高,腐蚀速率达到最高值的温度范围一般保持在40~80℃之间。结论温度对X70钢CO2腐蚀的影响与CO2分压密切相关,相同温度下,随着CO2分压的增加,腐蚀速率增大,相应的腐蚀速率达到最高值的温度也越来越高;孤立地说某一温度值下,CO2腐蚀速率达到最高值这一说法不准确。 相似文献
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The effect of corrosion on the tensile behavior of an as‐cast AZ91 alloy was investigated via systematical experiments. The corrosion residual strength of the AZ91 magnesium alloy is approximately negative linear dependent on the extreme depth of corrosion pit, which was quantitatively obtained by the corrosion morphology analysis and the statistic analysis. Experimental results reveal that the corrosion residual strength of the AZ91 magnesium alloy dropped quickly in the first 40 h due to the initiation and development of the corrosion pit and subsequently decreased slowly as a result of the development of the corrosion pit encountered the β phase. The β phase at the grain boundary of the primary α phase acts as an effective barrier to prevent the development of the corrosion pit into the alloy matrix and thus remarkably prevents the drop of the corrosion residual strength. In general, the variation of the corrosion residual strength exhibits an exponential decay regulation within the testing time. Consequently, the empirical prediction of the corrosion residual strength was given with regard to the variation of the corrosion residual strength varied with the immersion time. 相似文献
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本文对一台水套加热炉烟气系统的腐蚀情况进行了现场调查,分析了导致水套加热炉的烟气腐蚀的原因,阐建亍腐蚀机理,纠正了四川天然气田生产中设计水套加热炉只考虑硫化氢腐蚀,忽略烟气中二氧化碳腐蚀的论点。在使用和制造方面提出相应的建议方案。 相似文献
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Morphology of the corroded surface of low alloy steels beneath rust after long-term exposure test in the atmospheric environment was analyzed. The form of the corroded surface was measured with the laser displacement sensor scanning the surface. The resultant height map was divided by the mesh and the maximum corrosion depth was calculated in each cell. The maximum depth was arranged by the extreme value analysis. From this analysis two kinds of corrosion patterns were distinguished; i.e., uniform corrosion and local corrosion. Electrolytic iron shows the only uniform corrosion pattern. The addition of Cu, Ni and Cr changed the form of the corroded surface from the uniform corrosion to the combined pattern (uniform corrosion + local corrosion). The addition of Cr has a marked effect in changing the corrosion pattern. 相似文献
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Feng Ge Lin Fan Jianming Liang Kun Pang Han Li Xin Wang Zhongyu Cui 《金属学报(英文版)》2021,34(12):1679-1694
The corrosion evolution of 2024-T351 and 7075-T651 aluminum alloys in the thin electrolyte layer (TEL) and wet-dry alter-nating cycle (WDAC) environment is studied in this work.The results show that in the TEL environment,the competitive effect between H+ that accelerates corrosion reactions and deposition of aluminum sulfate that impedes corrosion attacks exists during the corrosion exposure.The difference is that with increasing HSO3-,subsurface intergranular corrosion on 2024-T351 is promoted to form exfoliation corrosion eventually and the degree of exfoliation corrosion begins to decrease because the blocking effect of aluminum sulfate exceeds the expediting effect of H+.For 7075-T651,the corrosion area and the corrosion diameter decrease gradually,which is attributed to the HSO3-enhanced deposition of corrosion products and their blocking effect.In the WDAC environment,the corrosion processes of 2024-T351 and 7075-T651 are the acidic dissolution of the matrix during the soaking phase.When the HSO3-concentration is high enough (0.1 M),the inhibiting effect of aluminum sulfate becomes the dominant factor. 相似文献
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Essentially, the corrosion process of the steel bar in reinforcing concrete structures is a series of electrochemical reactions. Therefore, the released energy during these reactions provides the opportunities to identify the corrosion status and power the wireless corrosion monitoring sensors. Furthermore, the recognition of the corrosion status has been realized with active monitoring techniques (AMTs) and passive monitoring techniques (PMTs). Additionally, the sensor mote platform that harvests the corrosion energy has been designed for corrosion monitoring, and then how to network these sensors to remotely access the corrosion data has been discussed. The preliminary experiment has been conducted to validate the micro corrosion energy. 相似文献
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The corrosion behaviour of wrought Mg-Zn-Y-Zr alloy was investigated by corrosion morphology observation and electrochemical measurement. The results indicate that the corrosion process can be divided into three stages, corresponding to three types of corrosion features. At the initial stage, corrosion occurred surrounding the second phases, which was driven by galvanic couple effect; at the middle stage, filiform corrosion was found in the central regions of α Mg matrix; at the final stage, pitting corrosion presented around the second phases. The second phases have a great effect on the corrosion process of Mg-Zn-Y-Zr alloy. 相似文献