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发动机工作过程中压气机叶片断裂,分解检查后根据损伤情况确定了首断件;通过对首断件断口宏观分析,确定断裂性质为疲劳断裂,起始于进气边一侧;断口显微分析结果表明:叶片断裂系起始于腐蚀损伤的疲劳断裂;漆层分析表明基体腐蚀损伤的原因是断口区漆层破损,在高湿和含盐环境下,腐蚀介质沉积在漆层破损处,叶片在破损处出现晶间腐蚀,萌生裂纹并扩展,直至断裂,漆层破损的原因为外来物打伤;针对故障原因,细化了发动机低压压气机二级转子叶片外场检查方法。 相似文献
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斜拉桥钢索坠落事故原因分析 总被引:5,自引:0,他引:5
对斜拉桥钢索附落后进行失效分析,对钢丝的形貌,表面腐蚀产物以及断口进行观察,检验与分析。结果表明,钢索坠落的 钢索的表面保护不完善,导致钢丝被严重腐蚀而造成断裂。 相似文献
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发动机Ⅰ级压气机转子叶片断裂分析 总被引:5,自引:2,他引:5
本文分析了某型发动机Ⅰ级压气机转子叶片断裂故障.叶片为低周疲劳断裂.叶片颤振裕度不大,在工作转速范围内产生颤振导致叶片承受较大的动应力是其疲劳断裂的主要原因.叶片表面的腐蚀坑是其疲劳断裂的另一促进因素.通过改用低展弦比的叶片,并增加叶片调频措施,提高了叶片的颤振裕度,避免了Ⅰ级压气机转子叶片的颤振疲劳断裂. 相似文献
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采用RH402定氢仪和盐雾腐蚀试验方法研究了索缆用镀锌钢丝在模拟酸雨腐蚀介质中的腐蚀行为,并用XRD表征腐蚀产物.结果表明,经2.5个月腐蚀后,位于索缆外层钢丝的镀锌层发生局部耗尽,而钢丝的氢含量随暴露时间延长呈增加趋势;经2个月和3个月腐蚀的索缆镀锌钢丝的主要腐蚀产物分别为3Zn(OH)_2·ZnSO_4·5H_2O和ZnSO_3·2H_2O与Fe_6(OH)_(12)CO_3.提出三个腐蚀阶段以描述索缆镀锌钢丝在模拟酸雨中的腐蚀过程. 相似文献
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发动机工作过程中出现燃气温度偏高的异常现象,返厂试车过程中Ⅱ级、Ⅲ级压气机转子叶片发生断裂。通过分解检查和理化分析,确定各断裂叶片的断裂性质及首断件;从设计、制造、装配、使用方面对首断件断裂原因进行分析,并采用整机模拟燃气温度偏高试验和压气机叶片叶尖振幅测量试验对断裂原因进行验证。结果表明:Ⅱ级压气机部分转子叶片发生高周疲劳断裂,为首断件;发动机严重进气畸变状态下,燃气温度偏高,Ⅱ级转子叶片一阶弯曲振动应力过高;可调叶片角度不准确、非正常激励频率是导致压气机叶片断裂的原因。 相似文献
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采用扫描电镜和能谱成分分析,对70高碳钢丝拉拔过程中出现的断裂问题进行了分析.结果表明,钢丝断口主要有平面状和杯锥状两种,其断裂类型为脆性断裂和韧性断裂.拉拔过程中,造成70高碳钢丝断裂的主要原因是钢丝内存在成分偏析、较大的夹杂物以及钢丝表面缺陷等,并提出有效措施解决这些问题. 相似文献
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The aim of this paper is to study the corrosion resistance of industrial coatings of metallic alloys including certain amount of process-induced porosity. Surface damages during a simulated corrosion process are investigated using Monte Carlo simulation technique and compared to corrosion response (dissolution currents). In this simulation, a 3D grid of the coating is subject to an electrolyte attack under potentiostatic conditions. The surface damages are related to a controlled dissolution process governed by dissolution probability, roughness, porosity size and fraction. In order to validate the model results, theoretical I = f(t) curves are compared to corrosion behaviour of Fe-40Al samples pointing out critical parameters affecting current density and exposed area. Predictions relating the porosity level to corrosion behaviour are established and discussed. The main conclusions focus on a primary effect of pore size and connectivity and a secondary effect of porosity level in the considered process window (porosity levels between 5.8% and 7.8%). The experimental work shows that the porosity effect could not explain all observed trends and a deeper examination of the microstructure reveals another candidate (unmolten particles) which is expected to vary both pore connectivity and dissolution events. 相似文献
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大港常减压装置的腐蚀与防护措施 总被引:1,自引:1,他引:1
总结分析了大港石化公司常减压装置在加工大港原油过程中出现的腐蚀情况,讨论了产生腐蚀的原因。介绍了目前所采取的防腐蚀措施,并提出加强生产管理,强化监测和检测技术的运用等具体的改进建议。 相似文献
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针对Mg在航空润滑油中的腐蚀特征,利用交流阻抗技 术,建立一种油品对Mg腐蚀程度的快速检验方法.应用这种方法,检验了Mg在几种不同的航 空润滑油中腐蚀状况,与实际应用情况一致. 相似文献
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Cristina Chiavari Carla Martini Lars-Gunnar Johansson Alf Åslund 《Corrosion Science》2008,50(9):2444-2455
The corrosion of lead-rich pipes in historical organs in different parts of Europe has been investigated. The influence of the environment and the composition and microstructure of the pipe metal was studied. Pipe corrosion was documented by visual inspection (boroscope). The corrosion attack and the composition and microstructure of the metal were characterized by OM, SEM, XRD, IC and FAAS. It is shown that the degree of corrosion of the pipes is correlated to the concentration of gaseous acetic and formic acid in the organ. The organic acids are emitted by the wood from which the wind system is built. It is also shown that pipe corrosion decreases with increasing tin content in the range 0-4% (wt). Possible conservation strategies are discussed. 相似文献