氮化钒的研究进展

氮化钒是一种新型的钢添加剂,能增加钢的耐磨性、韧性、强度、硬度、延展性及抗疲劳性等综合机械性能.综述了氮化钒的制备新进展,指出了氮化钒制备技术的发展方向.     

氮化钒制备技术发展历程及其应用

简要介绍了氮化钒物理化学性质,详细介绍国内外氮化钒制备技术的发展历程.氮化钒主要有两种制备方法,即高温真空制备和高温非真空制备,近年来也出现了一些新方法.同时对氮化钒的应用进行了综述,它不仅成为微合金钢中重要的合金添加剂,还开拓了催化剂、工具涂层和微电子等应用领域.     

氮化钒制备技术的发展及应用

简要介绍了氮化钒的物理化学性质,详细介绍了国内外氮化钒制备技术的发展历程.氮化钒主要有两种制备方法,即高温真空制备和高温非真空制备,近年来也出现了一些新方法.对氮化钒的应用进行了综述,它不仅成为了微合金钢中重要的合金添加剂,还开拓了催化剂、工具涂层和微电子等应用领域.     

目前国内氮化钒生产情况浅析

对氮化钒的用途、生产工艺、生产设备及国内氮化钒的生产情况进行了介绍。从目前国内氮化钒生产情况可知,国内氮化钒目前呈现出众多厂家在纷纷上马和扩张,增势迅猛,拥有钒资源的企业将占领氮化钒的市场高地。     

竖式中频炉加工氮化钒VN16技术研究

研究了利用竖式中频炉加工氮化钒VN16产品的技术。通过对氮化钒合成过程中的反应机理、反应条件等试验分析,结合工业化试验,实现了利用竖式中频炉将VN12以低成本加工成VN16产品,使氮化钒产品达到了增值的目标。     

竖式中频炉连续工业化生产氮化钒

对电加热隧道窑、工业微波炉等生产氮化钒的工艺作了比较,研究了竖式中频炉连续工业化生产氮化钒技术,介绍了竖式中频炉的生产过程,生产过程中遇到的问题以及解决办法.与推板窑生产氮化钒相比,在产能相同条件下,竖式中频炉的能源、耗材等损耗更低.     

攀钢加快氮化钒产业化进程

目前一直被美国所垄断的氮化钒生产技术及产品市场 ,有望不久在攀钢变为国产化的现实。由攀枝花钢铁研究院负责的“用三氧化二钒制取氮化钒技术研究” ,现已完成半工业试验 ,进入与设计、制造厂家联合攻关时期 ,计划 2 0 0 0年底研制出符合攀钢工艺特点的工业生产设备。氮化钒作为炼钢添加剂原料 ,与使用高钒铁相比 ,既可以少用 2 0 %的钒 ,又可以提高钢材的强度。由于氮化钒生产技术难度大、工业化成本高 ,致使国内外产业化进程步履艰难 ,只有美国独霸天下。攀钢科技人员以开发具有中国人自主知识产权的氮化钒产品为己任 ,在国外严密封锁技…     

攀钢钒氮合金的应用及市场前景

介绍了国内外钒氮合金的生产技术及攀钢在研究制取氮化钒技术方面的进展及其应用,同时对钒氮合金产品的市场前景作了预测。     

铁元素在氮化钒铁中的赋存状态

采用化学分析,XRD,SEM等检测手段,对闪速燃烧工艺制备的氮化钒铁中铁元素的赋存状态进行了系统研究。实验结果表明:以FeV80为原料,高温下进行氮化反应,FeV80颗粒的钒原子氮化形成氮化钒包覆层,随着氮化反应的进行,氮化钒含量和铁含量相对增多,钒的氮化难度逐渐增大。实验产品中,铁主要以Fe形势存在,不均匀分布于氮化钒颗粒内部。     

三级钢筋钒合金化的实践与研究

承钢冶炼三级钢试验了钒铁、氮化钒和氮化钒铁3种不同的钒合金,钢筋性能均满足用户要求。通过对比分析其成分控制,认为对于钒吸收率,氮化钒铁最高、氮化钒次之、钒铁最低。对比其钢筋性能,在碳当量相同时,认为加氮化钒的钢筋其屈服强度和抗拉强度最高,氮化钒铁次之,钒铁最低,对低成本冶炼三级钢具有指导意义。     

纳米级氮化钒最佳纳米化尺度的计算研究

为了研究纳米氮化钒添加到钢中的性能优势,通过有关纳米级氮化钒颗粒所含的晶胞数、原子数以及表面原子数的计算,得到相关纳米氮化钒结构参数的表征,并结合纳米微粒的特性对纳米氮化钒的最佳纳米化尺度进行模拟计算。结果表明,纳米级氮化钒的最佳纳米化尺度为200 nm,此时颗粒内的总原子数和平行于(001)面原子数达到平衡。     

Creep inhibition at grain boundaries in a stainless steel

The inhibition of creep in a vanadium alloyed austenitic stainless steel has been found to rely upon heterogeneous precipitation of vanadium nitride both on matrix and grain bound-ary dislocations together with the formation of M₂₃C₆ grain boundary carbides. The effect of these precipitation reactions on the separate stages of the creep test has been investi-gated microstructurally, particularly with reference to the processes occurring at grain boundaries. Dislocation configurations in grain boundaries, especially in the region of grain boundary carbides are modified by the presence of vanadium nitride precipitates. It is suggested that the roles of M₂₃C₆ and vanadium nitride precipitation during creep of this steel are interrelated and complimentary in reducing creep rates and extending creep ductility.     

Use of aluminum nitride in melting a V-Al-N master alloy

The possibility to use aluminum nitride as a nitriding agent for out-of-furnace aluminothermic melting of V-Al-N master alloys is studied and tested. It has been found that the replacement of nitrided vanadium by aluminum nitride in a charge for melting does not change the phase composition of the master alloy and the uniformity of the distribution of nitride inclusions in the ingot volume. The nitrogen-containing phase of the V-Al-N master alloy is represented by aluminum nitride. The mean values of the structural parameters of the master alloys melted from charges containing nitrided vanadium or aluminum nitride are identical.     

Low carbon manganese steels microalloyed with vanadium and nitrogen

With the objective of studying the effect of vanadium and nitrogen microalloying on microstructure and strength of low carbon steels with different manganese contents, three series of low carbon steels (0.1% C) with manganese content (between 0.8 and 3.5%), vanadium content (up to 0.17%) and nitrogen content (up to 0.025%) have been designed and investigated in the hot forging condition using a preheating and finish forging temperatures of 1200 and 950°C, respectively. Steels with a manganese content up to 2.3% revealed ferrite-pearlite structures, whereas higher manganese contents from 2.7 to 3.5% resulted in the formation of bainitic structures. A pronounced effect of manganese on the mechanical properties of steels was detected at lower manganese contents < 1.5%, due to solid solution and grain refining effects, and higher manganese contents > 2.3, due to bainite formation. Manganese content in the range of 1.5-2.3% had less pronounced effect due to solely solid solution hardening. Vanadium microalloying effectively increased the strength of steels through solely precipitation strengthening or both precipitation strengthening and grain refining effect. The effectiveness of vanadium was greatly enhanced by increasing the nitrogen content. The grain refinement of vanadium-nitrogen microalloying seems to be due to inhibition of austenite grain growth as a result of precipitation of vanadium nitride in austenite during forging. Precipitation strengthening of these steels is achieved by precipitation of vanadium carbide and nitride in ferrite or bainite. Nitrogen enhanced the precipitation strengthening of vanadium microalloyed steels which could be attributed to the finer vanadium nitride dispersion precipitates compared with vanadium carbide. Up to 70% of the total nitrogen content of steel precipitates as vanadium nitride which could be achieved with V/N ratio of about 6-7. Microalloying of low carbon-manganese steels (0.1% C and 1.8% Mn) with 0.15% vanadium and 0.025% nitrogen was found to be effective in attaining high levels of yield and ultimate tensile strengths of 835 and 940 N/mm², respectively in the forging condition.     

还原氮化五氧化二钒制备氮化钒的研究

对还原氮化制各氮化钒的过程进行了理论分析和实验探讨。结果表明，五氯化二钒还原过程中同时发生了直接还原和间接还原，在高温氮化条件下巳生成的氮化钒又转化为碳化钒。本试验条件下直接还原的开始温度为656K，氮化的开始温度为1160K，氮化钒转化为碳化钒的温度为1560K。间接还原发生的可能性与配碳系数有关，配碳系数越大，其发生的可能性越大。     

偏钒酸铵一步法制备氮化钒研究

在热力学计算基础上,通过热重—差热试验的分析,对偏钒酸铵碳热还原制备氮化钒的过程进行了探索,研究了原料配碳比和反应温度对产物物相和成分的影响。结果表明,配碳比为理论碳比时氮化产物氮含量最高,碳含量随着配碳比增加而升高。一步法制备氮化钒的过程是钒氧化物的碳热还原和氮化同时进行的耦合反应。     

Surface Characteristics and Hardness Variations in Electrical Discharge Machining of Enhanced Nitrogen in Vanadium Steels

Metallurgical and Materials Transactions B - Enhanced nitrogen in steels containing vanadium causes fine precipitates of vanadium nitride, which improve the hardenability properties. However,...