球墨铸铁材料制造液化石油气阀门的可行性研究

本文根据液化石油气阀门的使用工况特性,分析了在我国生产符合美国ASTMA395标准要求的优质球墨铸铁以代替铸钢制造液化石油气阀门的可行性。     

低温阀门

低温阀门上海良工阀门厂蔡惠君１．前言现代科学技术的发展，液化石油气、液化天然气、液氧和液氢等得到广泛应用，这些物质的液化分馏、运输和贮存都需要大量使用低温阀门。在乙烯、甲醇和合成氨等大型石化装置上及制冷和低温工程上也需要大量使用低温阀门。随着低温工业...     

弹簧式大口径过流阀设计

介绍了液化石油气输送装置用大口径过流阀的工作原理和结构特点,分析了以水代气检测阀门性能的可行性,论述了根据流量(流速)试验结果微调弹簧可以保证阀门自动关闭。     

液化石油气汽车应用初探

通过液化石油气与高级汽油的性能比较，展示了车用液化石油气广阔的应用前景．结合车用液化石油气系统的使用情况，通过系统构造、工作原理等阐述，论证了加快开发研制车用液化石油气系统和液化石油气汽车推广应用的可能性和必要性。     

液化石油气切割

液化石油气切割,就是利用液化石油气(通常主要成分是丙烷和丁烷)代替乙炔的切割过程。它具有成本低,切割质量好,使用方便,安全可靠等优点。一、液化石油气割炬液化石油气与乙炔气的燃烧特性不同,所以应当使用专门的液化石油气     

基于云聚合远程监控的瓶装液化石油气流转跟踪系统

考虑到传统系统在瓶装液化石油气流转跟踪中存在功能无法满足用户要求、性能差的问题,提出了基于云聚合远程监控的瓶装液化石油气流转跟踪系统。设计瓶装液化石油气流转跟踪系统架构、流转信息采集模块和液化石油气流转跟踪模块,通过分析液化石油气流转安全性的影响因素,提取流转路径的特征值,构建液化石油气流转路径之间的时空关系矩阵;利用云聚合远程监控技术,设计了液化石油气流转跟踪算法,实现了瓶装液化石油气的流转跟踪。测试结果表明,所提系统不仅在功能上可以满足用户需求,还可以通过提高跟踪成功率和吞吐量,提高系统的性能。     

液化石油气汽车应用初探

通过液化石油气与高级汽油的性能比较，展示了车用液化石油气广阔的应用前景。结合车用液化石油所系统的使用情况，通过系统结构、工作原理等阐述，论证了加快开发研制车用液化石油气系统和液化石油气汽车推广应用的可能性和必要性。     

液化石油气钢瓶爆炸失效分析

通过宏观形貌、断口边缘壁厚、化学成分、断口形貌及腐蚀产物成分、显微组织检验等,对液化石油气钢瓶爆炸原因进行分析。结果显示:钢瓶炸成两半,仅靠一部分环焊缝相连,表明爆炸时能量非常高;钢瓶内壁未见明显腐蚀,断口为韧性断口,表明钢瓶爆炸与钢瓶本身质量及液化气的腐蚀无关;钢瓶内壁和断口附着物内C含量很高,这是液化石油气不完全燃烧产生的碳黑;阀门内部存在灰迹,表明在切割过程中产生回火,瓶内气体燃烧导致钢瓶产生化学爆炸。     

液化石油气铁路罐车设计

1 主要设计依据液化石油气罐车的设计与一般罐车的设计有所区别,本文着重介绍液化石油气罐车设计时应考虑的主要问题。设计的主要依据有:液化石油气罐车设计任务书;化工部《液化气体铁路罐车安全管理     

叉车发动机采用液化石油气的试验

本文介绍了与CPQ30叉车配套的HZ492GF型汽油机使用液化石油气的试验情况,推荐了适用的液化石油气、汽油双燃料供给系统。从环境保护、经济效益、资源合理利用角度看,在我国液化石油气供应方便的地区具有重要的现实意义。     

面向21世纪的曲轴新材料

对发动机曲轴材料作了综合介绍。根据它的发展历史以及对各种种材料的化学成分、组织、性能、加工工艺、成本价格的比较分析,说明其发展趋势是以球铁曲轴替代锻钢曲轴,以铸态珠光体球铁曲轴替代热处理曲轴。球铁代钢的关键是提高韧性,自行研制的ＱＴ７４０－３铸态珠光体球铁曲轴表明,铸态球铁性能达到了一个新高新。另外对几种曲轴新材料进行了分析。     

合金元素对室温油分级等温淬火贝氏体球铁组织和性能的影响

采用一种新的室温油分级等温淬火工艺获得低合金贝氏体球墨铸铁;研究了硼、铜、锰对贝氏体球墨铸铁组织和性能的影响,并讨论了球墨铸铁的性能滞后现象,即等温淬火后随时问延长硬度增加的现象。结果表明：硼和锰能提高硬度,降低韧性;铜提高韧性。合理加入合金元素有利于提高贝氏体球铁的性能。贝氏体球墨铸铁有性能滞后现象,其实质是溶质类拖曳作用。     

球墨铸铁耐磨机理的研究

球墨的润滑作用及其较小的应力集中系数一般被认为是球墨铸铁具有较好耐磨性的原因。但是,作用通过透射电镜观察,发现在球铁基体中先天地具有较高的位错密度,同时也观察到在石墨球周围有一个密度更高的位错带存在。磨损试验的结果表明：试样的位错密度愈高,球铁的耐磨性愈好。这种在基体中有较高密度位错存在的事实就可能认为是球铁耐磨机理的所在。     

FEM analysis of erosive wear

Surface damage caused by the impact of dispersed particles in gas or liquid flow is called “erosion”. Much attention has been paid to this phenomenon as one of the most serious problems to be solved, particularly concerning pipe-bends or valves in pneumatic conveying systems. But the phenomena of erosive wear are so complicated and vary depending on the factors of not only the kinds of material, hardness, shapes, sizes and mechanical properties of the particles, but also of blasting angles and velocity.

For the purpose of this study, mild steel was prepared and erosion wear tests were carried out. Steel grits were impacted against target materials at different incident angles. The results showed that the wear losses varied markedly as a function of the impact angles, and that the maximum wear occurred at specific angles. Maximum wear occurred at 20–30° for mild steel, and 60° for ductile iron. This impact angle dependence of wear was simulated by Tabor’s theory and FEM which could analyze the plastic deformation of alloy surface as a result of a single particle impact. In the case of both mild steel and ductile cast iron, it was found that the impact angles play a very important and valid role in the corrosion process.     

奥贝球铁蜗轮在阀门电动装置上的应用

分析了热处理工艺中奥氏体化温度和时间、等温淬火温度和时间对奥贝球铁性能的影响。确定了阀门驱动装置用奥贝球铁材料蜗轮的生产工艺。通过装机试验验证,研制的奥贝球铁材料蜗轮满足使用性能要求,降低了生产成本。     

改善铁素体球铁曲轴切削加工性能的研究

为改善铁素体球铁曲轴毛坯切削加工性能,分析探讨了铁素体的固溶强化机理,对材料的化学成分、力学性能和金相组织进行了分析比较。结果表明,影响铁素体球铁曲轴硬度的主要元素是硅,在试验范围内,铁素体球铁硅含量与其硬度成正比;通过调整硅含量,严格控制球铁中其他元素的含量并保持基体中铁素体数量的一致性,可以达到控制曲轴硬度,使铸造的曲轴毛坯完全满足自动化生产线对其切削加工性能的要求。     

Effects of single-pass laser heat treatment on erosion behavior of cast irons

A single-pass laser heat treatment was performed on the surfaces of pearlitic gray and ductile cast irons using a 5 kW continuous wave CO₂ gas laser. Surface-hardened layers affect solid particle impingement erosion in that, for given abrasive flow conditions, the erosion rate of laser-treated gray iron was five times greater than that of untreated gray iron while the erosion rate of laser-treated ductile iron was 25 times greater than that of untreated ductile iron. The erosion mechanisms of gray iron included micromachining and ploughing in the untreated condition and intergranular cracking in the laser-treated condition. In contrast, ductile iron was eroded by severe plastic deformation and tearing in the untreated condition and by the fatigue mechanism in the laser-treated condition.     

Development and characterization of a wear resistant bainite/martensite ductile iron by combination of alloying and a controlled cooling heat-treatment

In this paper, a bainite/martensite (B/M) dual-phase ductile iron was fabricated by combining alloying and a controlled cooling heat-treatment. The microstructure, the mechanical properties and the wear performance were investigated and discussed. The ductile iron containing 3.2–3.8 wt.% carbon was alloyed with 2.5–3.0 wt.% manganese and 2.5–3.0 wt.% silicon. In general, manganese is no more than 0.7 wt.% and silicon <2.5 wt.% in commercial grade lower-bainite ductile irons. So, manganese contained in the ductile iron in this work is several times higher, and silicon slightly higher. In order to control the phase transition in the ductile iron during the heat-treatment, its continuous cooling transformation (CCT) curve was determined. The controlled cooling heat-treatment process was determined according to the CCT curve, which included three stages. The first stage was water quenching of the sample rapidly from the austenization temperature to a temperature below 350°C in a few minutes. The second stage was heat preservation of the sample from the spraying end temperature to 200°C in 2 h. The last stage was air cooling of the sample from 200°C to RT. According to the analysis using the scanning electron microscope (SEM) and the X-ray diffraction (XRD), the matrix of the ductile iron had a microstructure of bainite, martensite and a little retained austenite. The hardness and impact toughness of the heat-treated ductile iron were HRC 51.5 and 21.7 J/cm², respectively. The high values of the hardness and toughness were attributed to (1) the refined structure, (2) the presence of B/M dual-phase and (3) the presence of retained austenite. The impact abrasive wear resistance of the B/M ductile iron was observed to be comparable with that of a high chrome cast iron, and twice that of Mn13 steel.     

球墨铸铁断裂韧度的可靠性分析

通常球墨铸铁与其他铸铁材料一样被认为属于脆性材料，断裂韧度应该用线弹性力学理论进行研究。本文发现由于球墨铸铁中的石墨呈球状，当裂纹通过石墨时，裂纹扩展机理将发生相应的变化，结果显示用弹一塑性理论来研究球墨铸铁的断裂韧度是适应和有效的。对可靠度为95％球墨铸铁断裂韧度的区间估计进行分析，以便对工程中的断裂韧度提供相关的数据。     

低碳球墨铸铁石墨核心的组成与结构分析

低碳球墨铸铁是经SX变质剂处理以后获得的一种新材料,其中的石墨细小、圆整、分布面广;对其石墨球进行了扫描电镜、电子探针及透射电镜分析。结果表明：低碳球墨铸铁中的石墨是以锰、钙等的硫化物与氧化物作为基底形核并长大形成的。