阀芯强结合高密度涂层工艺和装备研究

发布时间：2018-01-22 02:11

本文关键词： 热喷涂自熔性镍基/不锈钢混合粉末炉内重熔低温性能装备　出处：《上海工程技术大学》2016年硕士论文　论文类型：学位论文

【摘要】：液化天然气作为新能源已经被广泛的应用在居民日常生活中,并且每年的需求量持续高速增长。液化天然气容易扩散和泄漏致使其在生产、接收、运输和气化过程中对装置的安全性要求极高。而低温阀门对其系统的安全可靠运行具有极为重要的作用。由于低温阀门的工作条件较为苛刻,因此开展材料低温性能和相关低温阀门装备的研究十分必要。本文采用超音速火焰喷涂技术对阀芯材料试样表面进行加工,分别喷涂自熔性镍合金粉末涂层和自熔性镍合金/不锈钢混合粉末涂层,并选择部分喷涂后的式样进行炉内重熔工艺的处理,然后对所有的试验样品进行低温冲击试验。在低温冲击实验后,对所有的涂层进行涂层微观组织结构分析、孔隙率的变化分析、涂层XRD物相分析以及硬度梯度测试、涂层粘结强度的测试和摩擦磨损测试。通过上述试验数据的对比得出以下结论:喷涂后采用炉内重熔后处理工艺,明显的降低涂层的孔隙率,提高涂层与基体的粘结强度,同时涂层与基体之间的结合方式也由“机械结合”向“冶金结合”转变,涂层的硬度和耐磨损性也大大的提升了。综合对比分析,采用超音速火焰喷涂自熔性镍合金/不锈钢混合粉末涂层并经过炉内熔融处理后的涂层综合性能最优。最后,本文针对阀芯表面涂层强化的性能要求,提出了喷涂-激光重熔-滚压装置相结合的整体结构设计方案,可以有效提高阀芯表面的涂层性能,同时对低温阀门的密封结构、检测机构等装置的研究给出设计方案。基于超音速火焰喷涂加工和炉内熔融的后处理技术,可有效改善低温阀门材料的耐磨性和耐低温性能,减少阀门的检修频率,提高阀门的使用性能,并产生良好的经济效益。
[Abstract]:Liquefied natural gas (LNG), as a new energy source, has been widely used in the daily life of residents, and the annual demand continues to increase at a high speed. Liquefied natural gas (LNG) is easy to spread and leak, resulting in its production and reception. In the process of transportation and gasification, the safety requirements of the device are very high, and the cryogenic valve plays an extremely important role in the safe and reliable operation of its system, because of the harsh working conditions of the cryogenic valve. Therefore, it is necessary to study the low temperature performance of the material and the equipment of the relevant cryogenic valve. In this paper, the surface of the spool material sample is processed by supersonic flame spraying technology. Self-fluxing nickel alloy powder coating and self-fluxing nickel alloy / stainless steel mixed powder coating were sprayed respectively. Then all the samples were subjected to low temperature impact test. After the low temperature impact test, the microstructure of all coatings and the change of porosity were analyzed. Phase analysis and hardness gradient test of coating XRD, bond strength test and friction and wear test. Through the comparison of the above test data, the conclusion is as follows: after spraying, the furnace remelting and post-treatment process is adopted. The porosity of the coating is obviously reduced and the bond strength between the coating and the substrate is increased. Meanwhile, the bonding mode between the coating and the substrate is also changed from "mechanical bonding" to "metallurgical bonding". The hardness and wear resistance of the coating are also greatly improved. The comprehensive properties of the self-fluxing nickel alloy / stainless steel mixed powder coating sprayed by supersonic flame spray and treated by melting in furnace are optimal. Finally, the performance requirements of the coating strengthened on the valve core surface are discussed in this paper. The whole structure design scheme combined with spray laser remelting and rolling device is put forward which can effectively improve the coating performance of the valve core and seal the low temperature valve at the same time. Based on the technology of supersonic flame spraying and melting in furnace, the wear resistance and low temperature resistance of low temperature valve materials can be improved effectively. Reduce the frequency of valve maintenance, improve the valve performance, and produce good economic benefits.
【学位授予单位】：上海工程技术大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG174.4

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