铌氯代磺酚S光度法中乙醇（丙酮）作用探讨

通过实践证明，用氯代磺酚Ｓ光度法测定钢中铌的方法过程中，所引入的乙醇（丙酮），并非能加快络合物的形成（或者说能加快显色速度）。在该显色反应的体系中，其主要是有助于显色剂的质子化，降低及稳定了试剂背景的吸收，另一方面对配合反应起了一点增溶效果而已。     

氯代磺酚C分光光度法测定钒钛磁铁矿中铌

在采用氯代磺酚C分光光度法测定钒钛磁铁矿中铌时,存在试样较难分解的问题,同时试样中的钛易水解干扰显色,钒也会与氯代磺酚C发生络合反应从而干扰测定。实验采用盐酸-氢氟酸-硫酸(1+1)溶解试样,通过加入酒石酸作为掩蔽剂消除了钛和钒的干扰,实现了氯代磺酚C分光光度法对钒钛磁铁矿中铌的测定。实验表明,在0.5~3.0mol/L盐酸介质中,铌的质量浓度在0.050~0.500μg/mL范围内与其对应的吸光度符合比尔定律,相关系数为0.9999。方法的检出限为 0.002%(质量分数),测定下限为 0.005%(质量分数)。干扰试验表明,试样中共存元素对铌测定的干扰可忽略。采用实验方法测定3个钒钛磁铁矿试样中铌,结果的相对标准偏差(RSD,n=6)小于1.0%。按照实验方法测定6个钒钛磁铁矿样品,结果与电感耦合等离子体原子发射光谱法(ICP-AES)相吻合。     

丹宁沉淀——氯代磺酚S测定钢中铌的探讨

本文详细研究了丹宁沉淀铌(V)过程中钼(VI)的沉淀情况；显色时酒石酸，硫酸乙醇，EDTA，氯代磺酚S的用量影响，找到了一种准确测定钢中铌含量的分析方法。使用该方法，除钽外，其余元素皆不干扰，适用各种钢的日常分析和仲裁分析。     

光度分析法测定包头铁矿及其冶炼渣中铌

系统研究了铌（V）与氯代磺酚S的显色反应,优化了反应条件．考察了该显色体系的分析性能,研究了样品的分解方法,拟定了用光度法分析包头铁矿及其冶炼渣中铌的方案．     

丹宁沉淀-氯代磺酚S光度法测定钢中铌含量

本文详细研究了丹宁沉淀铌(Ⅴ)过程中钼(Ⅵ)的沉淀情况;显色时酒石酸、硫酸、乙醇、EDTA、氯代磺酚S的用量的影响,找到了一种准确测定钢中铌含量的分析方法.使用该方法,除钽外,其余元素皆不干扰,适用各种钢的日常分析和仲裁分析.     

高钼低铌钢中铌的测定

在高钼低铌钢中的铌的测定中,钼对铌的测定存在严重的干扰.本文介绍了使用显色剂氯代磺酚S在强酸条件下,加入掩敝剂消除钼离子的影响后,与铌生成11深蓝色的络合物.在3mol/L盐酸介质中,加入适量新型柠檬酸混合掩蔽剂就能有效地消除钼的干扰.通过多项平行试验筛选出合适的掩蔽剂用量、显色剂用量、给出加快络合反应速度的条件.本方法测定数据稳定,准确度高,速度快,能有效地应用于生产.     

氯代磺酚S光度法测定水中微量铜

探讨了氯代磺酚S与Cu（Ⅱ）的显色反应条件,在pH5的HAC－NaAc缓冲介质中,Cu（Ⅱ）与试剂形成1:1的蓝色配合物,其最大吸收峰位于635nm处,摩尔吸光系数。为2．03×104,Cu（Ⅱ）的浓度在0～40μg／25mL范围内遵守比耳定律。用于水中微量铜的测定,结果满意。     

丹宁沉淀-氯代磺酚S测定钢中铌

研究了丹宁沉淀铌过程中钼的沉淀情况；显色时酒石酸，硫酸乙醇，EDTA，氯代磺酚S的用量的影响，找到了一种准确测定钢中铌含量的分析方法，使用该方法，除钽外，其余元素皆不干扰，适用各种钢的日常分析和仲裁分析。     

分光光度法间接测定高炉生渣中氧化亚铁

利用生渣的还原特性,在pH为5-6的缓冲溶液中,加入显色剂,采用光度法间接测定生渣中氧化亚铁的含量,分析结果能满足生产的要求。     

Effect of Niobium on Transformations From Austenite to Ferrite in Low Carbon Steels

Niobium has an important effect on the transformation behaviour,grain size refinement and precipitation strengthening during hot rolling and subsequent cooling in low carbon steels,with even a low content of niobium having a strong effect on the transformation rate from austenite to ferrite.However,the effects of niobium on transformation behaviour have not been fully characterised and understood to date.This paper examines in detail austenite grain growth as a function of austenitisation time in high strength low alloy (HSLA) steels with three different niobium contents,together with the effect of niobium on the isothermal transformation kinetics from austenite to ferrite as a function of temperature.It is shown that austenite has the slowest grain growth rate in the steel with the highest niobium content.When austenite grain sizes are consistent,the steel with the highest niobium content was found to have the slowest transformation rate from austenite to ferrite.     

以铌铁作为铌矿替代原料生产高纯氧化铌的研究

以铌铁代替铌矿原料,通过常温低酸度溶解,纯水返铌等改良工艺更加高效、环保地生产高纯氧化铌。与传统工艺相比,该方法可以突破原料缺乏瓶颈,降低生产与环保成本。     

重量法测定草酸铌中的铌量

文章建立了重量法测定草酸铌中铌量的方法。通过采用正交试验优化了测定的工艺参数，将草酸铌灼烧成五氧化二铌，通过质量的减少测定草酸铌中铌量。该方法的相对标准偏差小于0．4％，通过与不同方法的结果对照，方法的准确度和精密度良好，操作简便快速，易于掌握，完全能够满足生产工艺的需要。     

Niobium in Engineering Steels for Automotive Applications

In the last decade, the European niobium consumption in automotive strip and sheet has more than tripled. The development of high strength and advanced high strength steel grades for strip and plate products focused upon constantly increasing strength levels combined with excellent fatigue properties as well as formability and weldability. Until now, the high potential of microalloyed steel has not been used to the same extent in forgings and springs. This paper reviews automotive components as transmissions, suspensions and springs highlighting new material solutions for special steels having optimized processing and in‐use properties. Special consideration is given to the metallurgical background as well as to examples for the processing and application of niobium microalloyed steel in forgings and springs from low carbon and higher carbon containing steels. Niobium metallurgy permits the reduction of carbon to meet more stringent end‐user requirements demanding high strength combined with improved toughness, fatigue strength and weldability at a competitive manufacturing cost.     

铜合金中铌的快速测定

基于盐酸介质中，铝与硫氰酸盐形成铝氧硫氰酸H[NbO(CNS)4]黄色络合物而能被乙酸乙酯所萃取。最大吸收峰位于385nm处，以铝盐消除溶样时所带入的氟离子。铌含量在0-12μg/15ml范围内有良好的线性关系。用于铜合金中铌的测定，结果满意。     

High Strength Low Alloy (HSLA) Steels in Building Construction

Majority of the buildings,including industrial buildings,are constructed using either structural steel (plates and structural shapes) or deformed bar steel reinforced concrete.Such buildings,however,must be designed to be safe and serviceable during construction and during use and occupancy.These objectives can be easily achieved by the use of steels having superior mechanical properties,ductility,weldability,fire resistance,etc.Over the years,the steel industry has made improvements in steel making technologies resulting in high strength low alloy (HSLA) steels with superior steel properties well suited for building construction.First part of this paper presents the structural design considerations,and the constructional considerations associated with the building structures in general,and steel structures in particular.This second part of the paper looks at the acceptance criteria for HSLA steels for North American building codes and construction.The third part of the paper presents the structural properties of currently available HSLA steels for building construction.The discussion focuses on hot-rolled structural steel shapes as well as deformed steel bars for concrete reinforcement.The paper argues that Niobium microalloying is the key to achieving superior properties in such steels.     

铌对低温钢组织及性能的影响

通过金相组织观察、低温冲击试验和拉伸试验及拉伸断口形貌观察,研究了铌对正火+调质处理低温钢组织及性能的影响。结果表明:铸态下随着试样中铌含量的增加,组织中珠光体片间距逐渐减小,经过930℃正火+900℃淬火+630℃回火热处理后,铌质量分数为0.039%的试样组织及综合性能最佳,组织为回火索氏体,-20、-40℃夏比冲击功分别达到44.4和28.4J,抗拉强度和屈服强度分别为995和885MPa,断后伸长率达到17.0%。     

铌微合金化高碳钢的连续冷却转变

在Geeble-1500热／力模拟试验机上测定了铌微合金化高碳钢与普通高碳钢变形后的连续冷却转变曲线，分析比较了它们的组织演变规律。实验结果表明，与普通高碳钢相比，含铌高碳钢的转变温度较高，A P两相区的温度范围较大(在所测定的冷速下，温度范围均在100℃以上)，且在相同冷速下，先共析铁素体的数量明显增多，而奥氏体晶粒较小。在本实验条件下，当冷速大于10℃／s时，含铌高碳钢转变后的珠光体片层间距较小；在冷速大于30℃／s时，其基体中出现贝氏体组织。     

Computer Model of Phase Transformation From Hot-Deformed Austenite in Niobium Microalloyed Steels

Based on thermodynamics and kinetics, a new mathematical model was developed to calculate the CCT diagrams and the transformation kinetics in low carbon niobium steels, in which the effect of deformation on the degree of supercooling was taken into account. The undercooling caused by deformation is the major reason for the increase of the starting transition temperature during continuous cooling. The critical cooling rate of bainite formation is within 2--5 ℃s for the studied niobium steels and deformation is suitable for the occurrence of pearlite. The ferrite volume fraction increases with the increase of the austenite boundary area, and decreases with the increase of the cooling rate. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with the measurements.