再制造盐浴清洗技术分析与应用

发布时间：2018-11-06 17:47

【摘要】：再制造工程作为新的制造业发展方向,具有产品质量好、资源利用率高等优点,能够制造出符合需要的机械产品并且解决大量的就业问题。再制造清洗技术作为再制造工程中的基础环节,为再制造产品的质量提供了基本保证。盐浴清洗技术由于具有温度高、性质稳定、用途广泛等优点,可以作为一种有效的清洗方法应用于再制造工程之中。作为盐浴清洗的介质,熔盐本身具有温度高、性质稳定、流动性好的优点。利用高温特性,能够加快清洗的速率；挥发性好保证了工作中材料损耗小；性质稳定降低了对清洗对象基体的腐蚀；好的流动性能够使清除下来的污染物快速地脱离零件基体表面。另外,熔盐本身具有好的渗透和浸润特性,能够更好地提升清洗的效果。目前国内对于盐浴清洗应用十分有限,研究相对较少。本文从熔盐的物理性质出发,寻求其应用于再制造清洗的理论基础。研究了熔盐的熔点、劣化温度、粘度变化、表面张力等性质,并对发动机积碳进行了清洗试验。利用差示扫描量热法对硝酸钾和亚硝酸钠混合熔盐进行了热物性分析,利用曲线得到了不同配比的熔盐的熔点和劣化温度,确定了其工作温度范围；利用蓝宝石法测量了熔盐的比热变化,为提高盐浴清洗的使用稳定性提供了理论支持。总结了几种液体粘度测量方法的原理,利用回转振荡法测量了硝酸钾和亚硝酸钠熔盐的粘度变化,得到了粘度曲线。根据目前国内外提出的大量的熔盐粘度近似计算公式进行了比较。根据测得的粘度数据,对其进行了数据拟合,得到了硝酸钾和亚硝酸钠粘度近似计算经验公式。界面张力体现了液体与固体之间的浸润和附着能力,根据最大气泡法,通过设计测量试验装置,测量了熔融状态的硝酸钾和亚硝酸钠熔盐的表面张力,得到了混合熔盐的表面张力与混合盐的组成和温度之间的关系。希望通过降低表面张力来提高作为清洗介质的熔盐与清洗对象之间的浸润程度,提升清洗效果。介绍发动机内部积碳的形成过程与危害,并以其为清洗目标,利用盐浴方式对其进行清洗,并对清洗结果行了试验验证,证明碱性盐浴清洗技术对积碳能够进行快速有效地清洗。
[Abstract]:As a new developing direction of manufacturing industry, remanufacturing engineering has the advantages of good product quality and high utilization of resources. It can produce mechanical products that meet the needs and solve a large number of employment problems. As a basic link in remanufacturing engineering, remanufacturing cleaning technology provides a basic guarantee for the quality of remanufactured products. Because of its high temperature, stable properties and wide applications, salt bath cleaning technology can be used as an effective cleaning method in remanufacturing engineering. As the medium of salt bath cleaning, molten salt has the advantages of high temperature, stable property and good fluidity. By using the high temperature characteristic, the cleaning rate can be accelerated, the volatility can ensure the low material loss in the work, the property stability reduces the corrosion to the cleaning object matrix. Good fluidity enables the removal of contaminants quickly off the surface of the part substrate. In addition, the molten salt itself has good permeation and wetting characteristics, which can improve the cleaning effect. At present, the application of salt bath cleaning in China is very limited, and the research is relatively few. Based on the physical properties of molten salt, the theoretical basis of its application in remanufacturing cleaning is sought. The melting point, deterioration temperature, viscosity change and surface tension of molten salt were studied. The thermal properties of the mixed molten salt of potassium nitrate and sodium nitrite were analyzed by differential scanning calorimetry. The melting point and deterioration temperature of the molten salt with different proportions were obtained by the curve, and the working temperature range was determined. The specific heat of molten salt was measured by sapphire method, which provided theoretical support for improving the stability of salt bath cleaning. The principle of several liquid viscosity measurement methods is summarized. The viscosity changes of potassium nitrate and sodium nitrite molten salt are measured by rotary oscillation method, and the viscosity curve is obtained. A large number of approximate formulas for calculating the viscosity of molten salt have been compared at home and abroad. According to the measured viscosity data, the empirical formulas for the approximate calculation of the viscosity of potassium nitrate and sodium nitrite were obtained. The interfacial tension reflects the soakage and adhesion between liquid and solid. According to the maximum bubble method, the surface tension of molten potassium nitrate and sodium nitrite molten salt is measured by designing a test device. The relationship between the surface tension of the mixed molten salt and the composition and temperature of the mixed salt is obtained. It is hoped that the wetting degree between molten salt as cleaning medium and cleaning object can be improved by reducing surface tension, and the cleaning effect can be improved. This paper introduces the formation process and hazard of carbon deposition in the engine, taking it as the cleaning target, using salt bath to clean it, and validates the cleaning result by experiment. It is proved that alkaline salt bath cleaning technology can clean carbon deposit quickly and effectively.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB490

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