【作者】 刘秋生；

【导师】 陶俊勇； 程远贵；

【作者基本信息】 国防科学技术大学 ， 机械工程， 2009， 硕士

【摘要】 钒以其超强的晶粒细化和沉淀强化作用,已经成为高强度钢的首先合金添加元素。因为钒和氮的结合比钒和碳的结合更加稳固、更加均匀,从而加强了钒的晶粒细化和沉淀强化作用,故钒的存在不再是钢中力图去除的有害元素,而是希望增加的有益元素。钢中直接加入钒和氮的最可靠方法是添加氮化钒。制备氮化钒的关键技术包括：氮化钒的工艺技术和工艺设备关键技术。氮化钒的工艺技术包含氮化钒的工艺温度技术、工艺气氛技术和工艺配方技术,它对提高氮化钒产品的氮质量百分比和钒质量百分比至关重要,而工艺设备关键技术是实现氮化钒工艺过程的重要保障。因此,本文针对氮化钒的工艺技术和工艺设备关键技术展开了研究工作。主要工作和研究内容如下：1.用热力学方法研究了常压条件下五氧化二钒与碳粉还原成氮化钒的反应机理。重点分析了各级碳化还原反应的开始温度与体系内一氧化碳气体分压的关系,研究了体系内氧气气体分压对碳化还原反应的影响,以及体系内氮气气分压对氮化反应截止温度的影响,体系内氧气气体分压对氮化产物氧化反应截止温度的影响。2.研究了常压条件下五氧化二钒与碳粉烧结反应过程的动力学问题。具体分析了各级反应温度与反应速率的关系,为解决五氧化二钒碳热还原氮化钒工艺中的氮质量百分比和钒质量百分比偏低的问题提供了理论依据。3.针对配碳系数、添加剂数量、氮化时间等三个因子,开展了影响对产品氮质量百分比、钒质量百分比的正交试验,通过正交试验统计和方差分析的方法,实现了氮化钒工艺配方和氮化时间的优化。4.研究了氮化钒工艺设备的关键技术。设计了氮化钒烧结工艺的时间—温度关系曲线和时间—气氛关系曲线,通过对烧结设备低温段、升温段和恒温段介质分析,以及热力学计算,设计了相应的温度场下,满足工艺条件的烧结设备内衬。总之,论文针对氮化钒工艺技术及工艺设备关键技术开展了氮化钒的工艺温度技术、工艺气氛技术、工艺配方技术及工艺设备内衬技术的研究,解决了常压条件下五氧化二钒碳热还原氮化钒工艺的氮质量百分比和钒质量百分比偏低和工艺设备的内衬腐蚀问题,试验证明常压条件下五氧化二钒碳热还原氮化钒工艺技术在工程上是合理可行的。更多还原

【Abstract】 Vanadium, with its strong grain refinement and precipitation strengthening effects, has become the primary alloy additive for high strength steel. As the integration between vanadium and nitrogen is more stable and homogeneous than that between vanadium and carbon, which intensifies the grain refinement and precipitation strengthening effects of vanadium, therefore the purpose of adding vanadium is no longer to eliminate harmful elements in steel but to increase beneficial elements hopefully. The most reliable way of adding vanadium and nitrogen into steel is adding vanadium nitride.Key technologies of vanadium nitride preparation include process technology of vanadium nitride and key technology of processing equipment. The former includes process temperature technology, process atmosphere technology and process formulation technology of vanadium nitride, which is very important for improving mass percentage of nitrogen and vanadium in vanadium nitride products; while the latter is a critical guarantee to the realization of process procedures of vanadium nitride. Main work and studying contents of the article are as follows:1. Using thermodynamic method to study the reaction mechanism of reducing vanadium pentoxide and carbon powder into vanadium nitride under normal pressure, focusing on analyzing the relationship between starting temperature of all levels of carbonization reduction reactions and partial pressure of carbon monoxide in the system, impact of oxygen partial pressure in the system to carbonization reduction reaction, impact of nitrogen partial pressure in the system to closing temperature of nitriding reaction and impact of oxygen partial pressure in the system to closing temperature of oxidation reaction of nitriding products.2. Studying the dynamics of sintering reaction between vanadium pentoxide and carbon powder under normal pressure, including analyzing the relationship between all levels of reaction temperature and reaction velocity, which provides theoretical basis for resolving the issue of low mass percentage of nitrogen and vanadium during the reduction of vanadium nitride.3. Conducting orthogonal tests that impact mass percentage of nitrogen and vanadium in product according to carbon adding coefficient, additive dosage and nitriding time and optimizing processing formulation and nitriding time of vanadium nitride via orthogonal test statistics and variance analysis.4. Studying key technology of processing equipment of vanadium nitride. The time-temperature relationship curve and time-atmosphere relationship curve of sintering vanadium nitride are designed and lining of sintering equipment that meets processing conditions is designed via media analysis to low-temperature section, heating section and high-temperature section of sintering equipment and thermodynamic calculations.In summary, the article studies process temperature technology, process atmosphere technology, process formulation technology and lining technology of process equipment with regard to process technologies and key technology of process equipment for vanadium nitride and resolves the issue of low mass percentage of nitrogen and vanadium in the reduction of vanadium nitride under normal pressure and the corrosion of lining of process equipment. Tests show that the process technology of reducing vanadium pentoxide and carbon powder into vanadium nitride under normal pressure is reasonable and feasible in engineering.更多还原