钢液氢含量检测技术研究

测量钢液氢含量的方法有离线定氢和在线定氢。离线定氢通过从钢液中取样,凝固后实验室检测氢含量。在线定氢通过测量出钢液的平衡氢分压后利用Sievert定律换算出氢含量。与离线定氢相比,在线定氢影响因素少,系统重现性好,测量周期短,满足真空处理、连铸等快节奏定氢的需要。     

金属中气体元素分析典型案例

金属中气体元素分析已经存在60余年,其检测方法不同于其他化学元素.论文列举5个典型案例(铝中氢、金属中氩、金属中氦、稀土钢中氢、(铝)镁中氧),以进行技术交流和讨论.铝中氢作为金属中气体分析之最难当之无愧,有研究尝试简化铝中氢分析方法,期望像钢样那样快速准确地得到结果,比如应用现有通用的脉冲熔融法反复试验上百次,未能成...     

重轨钢中的氢及其控制工艺

介绍了钢中氢对钢质量的影响以及对重轨钢的危害,对钢液中氢的检测方法和检测设备作了简单说明,阐述了采用转炉→LF→RH(VD)→连铸工艺生产重轨钢时,钢中氢的来源及其过程氢含量,并提出了有效控制重轨钢中氢含量的措施及实施效果。     

金属薄板的氢扩散试验

 金属板材氢扩散计算试验选用材料为40Cr及4Cr13轧制板材,运用电化学方法进行氢扩散试验。通过对薄板进行表面处理,且进行预镀镍及镀镍的处理,最终进行氢扩散系数的测定试验,并根据氢扩散试验得到的数据参数进行氢扩散系数的计算,最终得到两种钢的氢扩散系数。氢扩散计算试验适用于各种不同金属材料氢扩散系数的测定,为检测钢在使用过程中氢的积累提供基本参数及计算依据,且对于材料中氢的定量计算起到至关重要的作用。通过对两种材料成分及扩散系数的比较,进一步研究金属中合金元素质量分数对氢在金属中扩散的影响作用。     

钢液在线测氢技术的应用研究

由钢铁研究总院完成的“钢液在线测氢技术应用研究”利用钢铁研究总院开发研制的“钢液中在线测氢分析仪”,采用平衡分压法实现测量 ,即将测头浸入钢液 ,并向吹气管中吹入惰性气体 (氮气 ) ,钢液中的氢向氮气气泡中扩散 ,最后达到平衡。用仪器回收该平衡气体 ,通过热导检测器检测出钢液中的氢含量。这顶技术可应用于冶金系统及重型机械系统的炼钢、精炼领域。　　性能指标分别达到 :分辨率 0 .0 1× 10 - 6 ;分析精度± 2 % ;测量重现性± 0 .2× 10 - 6 ;测量范围 <10× 10 - 6 ;分析时间 <2 .5 m in;可显示并存储分析曲线 ;具有热导池保护…     

钢液中气体分析样取制样方法的完善

金属中气体元素氢、氧、氮三种填隙式相元素的分析俗称金属中气体分析。钢中氢对钢材造成很多严重缺陷，危害极大。氧对于把铁冶炼成钢是必不可少的，铁中杂质元素均通过氧化来去除或使之降低到需要的程度，但钢中的氧会形成氧化物夹杂引起钢组织不均匀，使工艺性能变坏。因此在冶炼后期会采取加入脱氧剂等方法降低钢中的氧。而钢中的氮在一定条件下可导致钢材的蓝     

熔融金属中氢的直接测定

熔融金属中氢的直接测定ＤｉｒｅｃｔＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＨｙｄｒｏｇｅｎｉｎＭｏｌｔｅｎＭｅｔａｌｓ摘自冶金部钢铁研究总院研究生秦卫东的硕士学位论文，导师：漆　邦钢和铝中的氢会对其性能造成危害。熔融金属中氢的溶解度受金属温度、环境湿度及金属成...     

钢液定氢的几种采样法及试样制备

1、绪言 氢在钢中只能产生有害的作用。它一直受到学术界的极大关心,七十年代间曾举行过三次有关研究钢中氢的国际学术会议。随着各自生产实践及氢脆事故的发生,金属中氢及其分析手段受到重视,并得到发展。 我国78年组织的“全国定氢攻关”活动经过二年工作,在采样枪、标钢、分析仪器     

脉冲加热-程序升温法研究金属中氦和氢的释放

在一次改造脉冲-热导氢测定仪的基础上,进行二次改造使其具备程序升温功能,应用两次改造后的不同组合,开展了金属中氦和氢热释放的研究。实验结果表明:金属中氦的热释放符合固溶态气体的释放特征,氦在样品熔点附近快速释放,未见高温分解的化合物峰;金属中氢提取未见缓慢热释放图谱,说明氢在固体中的扩散和迁移相对缓慢,固溶态的氢在样品熔点附近快速释放。两种仪器两次改造组合的分析发现脉冲热导法无法区分氦和氢,氦和氢同时释放构成同一个峰,因此,富氦样品必须应用脉冲红外等其他方法定氢,才能确保氢分析的准确性。由于日常普通样品贫氦,考察了7种普通金属中氦含量,探明其值均小于仪器检测限,不会影响到氢的定量分析结果。     

喷吹卤化物气体脱除钢液中的氢

此系美国专利技术。炼钢时为了消除钢液中的氢，一般采用真空脱气或喷吹惰性气体的方法，但对钢水量少而言．从设备投资费用和气体量考虑，这些方法不经济。美国航空化学品公司进行了将SF；、（”F等由化物气体吹入八95kg钢液中的小型试验，成功地脱去了钢水中的氢，随即由伯努利钢厂进行了处理81钢水的中间试验。喷吹脱氧一定时间后．钢液中的红含量降低到IXIO－‘以下。该项技术现已应用于生产中。喷吹卤化物气体脱除钢液中的氢     

稀土金属脱除氧杂质的新技术及驱动机制研究进展

介绍了活泼金属除气法、等离子体熔炼法和固溶氢原子除气法等稀土金属脱除氧杂质的新方法,详细归纳了将氧杂质含量限制在5×10-5以下的工艺条件.重点介绍新方法中引入活泼金属、氢等离子体、活性固溶氢原子等各种外部驱动因素的设计思想,提出提纯新技术的同时探究了痕量杂质的迁移规律及去除机制,深化对杂质存在形式、行为规律及提纯机理的认识.采用FAST-2D与Stefan数值模拟技术、18O₂示踪同位素标记技术、CALPHAD相图数据库模拟计算技术对稀土金属高纯化的新工艺提供理论指导与评价,加深对提纯驱动机制的理解.      

A Model for Calculating Hydrogen Solubility in Liquid Transition Metals

The documented experimental results of hydrogen solubility in different liquid metals were summarized according to the periodic table. It is found that the hydrogen solubility in liquid transition metals is much higher than in others and it changes regularly with the atomic number to form a V-shaped curve. It is supposed that the electron interaction between the hydrogen and metal atoms of the liquid is the major factor in determining hydrogen solubility in the liquid metal. Based on this consideration, a model was proposed for characterizing electron interaction and calculating the hydrogen solubility in various liquid metals according to the nearly free-electron theory. The calculated hydrogen solubility in liquid transition metals agrees well with the documented experimental results, and some undocumented results could be predicted.     

Development and Application of Hydrogen Storage

Hydrogen,as a secure,clean,efficient,and available energy source,will be successfully applied to reduce and eliminate greenhouse gas emissions.Hydrogen storage technology,which is one of the key challenges in developing hydrogen economy,will be solved through the unremitting efforts of scientists.The progress on hydrogen storage technology research and recent developments in hydrogen storage materials is reported.Commonly used storage methods,such as high-pressure gas or liquid,cannot satisfy future storage requirement.Hence,relatively advanced storage methods,such as the use of metal-organic framework hydrides and carbon materials,are being developed as promising alternatives.Combining chemical and physical hydrogen storage in certain materials has potential advantages among all storage methods.Intensive research has been conducted on metal hydrides to improve their electrochemical and gaseous hydrogen storage properties,including their hydrogen storage capacity,kinetics,cycle stability,pressure,and thermal response,which are dependent on the composition and structural feature of alloys.Efforts have been exerted on a group of magnesium-based hydrides,as promising candidates for competitive hydrogen storage,to decrease their desorption temperature and enhance their kinetics and cycle life.Further research is necessary to achieve the goal of practical application by adding an appropriate catalyst and through rapid quenching or ball milling.Improving the kinetics and cycle life of complex hydrides is also an important aspect for potential applications of hydrogen energy.     

Effect of hydrogen on the frequency of breaks in a metal during continuous casting of steel

Data from a number of metallurgical works in Ukraine are used to analyze the possibility of break formation in a metal at a various hydrogen content in a liquid steel during continuous casting. A critical hydrogen content in the metal to be cast at which the probability of breaks in the metal increases sharply is revealed. Possible mechanisms of the suspension of the skin of an ingot in a continuous-casting mold and of breaks in a metal are considered.     

New methods for the determination of hydrogen content of aluminum and its alloys: Part III. Quantitative Vacuum Gas Test (Straubbe-Pfeiffer Test) by use of a mass spectrometer

A new method is proposed for determining quantitatively the hydrogen content of molten aluminum directly in the cast house. It consists in measuring, with a small mass spectrometer (an industrial helium leak detector), the partial pressure of hydrogen evolved during solidification of a liquid metal sample at a reduced pressure of 1 Torr in a vacuum chamber,e. g. under operating conditions similar to the usual Vacuum Gas Test. A detailed investigation permits a definition of the following characteristics for the method. 1) The detection limit is on the order of 0.03 ml/100 g for a 200 g metal sample. 2) Dehydrogenation occurs essentially at the end of the solidification of pure metal or eutectics, and can be explained by the difference in solubility of hydrogen in liquid and solid aluminum. 3) The correlation between the phase diagram of the alloy to be studied and dehydrogenation permits the consideration of the dehydrogenation curve as a characteristic spectrum of the alloy. 4) No simple correlation could be established between hydrogen content and bubble nucleation. 5) Hydrogen contents derived from this method before casting an alloy are not significantly different from those obtained by a laboratory method on the solidified final product. 6) The time required for a determination (10 to 20 min) is short enough to allow a plot of the evolution of hydrogen content during a whole metal treatment cycle. 7) The new Vacuum Gas Test combines the information from the usual test for metal clean-liness (visible bubbles rucleated by the presence of inclusions) and the possibility of obtaining a quantitative value of the hydrogen content.     

Convective heat-transfer measurements in liquid metals under different fluid flow conditions

In this study an experimental method to measure convective heat transfer characteristics in liquid metals is presented. This method involves the immersion into a metal bath of a solid specimen whose melting point is equal to or lower than that of the metal or alloy in the metal bath, and which will not react chemically with the liquid metal or alloys used. The specimen should have a hollow bore whose opening is held above the surface of the liquid metal; immersion continues until such a time as the liquid metal penetrates the hollow bore. The apparent weight of the specimen is monitored to determine the rate at which the net downward force changes. Experimental results are reported for liquid aluminum, liquid copper, and liquid steel. Those experimental results were conducted under different fluid flow conditions. The applicability of this method to liquid slags is also discussed. Formerly Postdoctoral Research Fellow with the Department of Metallurgy and Materials Science, University of Toronto     

PRODUCTION OF SOME METAL POWDERS BY HYDROMETALLURGICAL PROCESSES

Abstract

Nickel, cobalt, copper, and iron powders can be manufactured by hydrometallurgical processes. It is possible to use a wide variety of materials, including waste solutions, as the metal-containing feed. Estimates of the capital cost of reduction autoclaves and ancillary equipment show the advantage of increasing the scale of the operation from 2 to 50 tons of metal produced per day.

A major factor in the economics of producing the powders is the cost of purifying the solutions to give a liquor from which metal of the desired purity can be precipitated. Liquid–liquid extraction does not appear to have been used so far in a refinery in which metal is precipitated by hydrogen. The possible application of the technique is examined briefly.

Metal powders can be precipitated directly by reducing with hydrogen some organic phases produced by liquid–liquid extraction of aqueous solutions containing several metals. A suitable solvent mixture is acarboxylic acid with hydrocarbon diluent. The total pressure necessary for reduction is lower than that required when water is the solvent.

An important factor in considering the use of hydrometallurgical methods for producing metal powders is that in some cases the cost of obtaining metal is competitive with any other kind of process, and the fact that it is formed as powder is an added advantage. Also it is possible to make powders with physical characteristics that can be controlled withinnarrow limits over a very wide range.     

The rate of hydrogen solution in liquid alloys

A study has been completed on the rate of hydrogen solution in inductively stirred liquid pure copper, nickel, cobalt, and several binary alloys of copper and of nickel. Results on the hydrogen solution rate in liquid pure iron also were obtained. A constant-volume Sieverts’ apparatus was used. The melts were exposed to hydrogen, and the rate of solution determined by the time change of gas pressure in the system. The rate of hydrogen solution for all pure metals in this study was controlled by transport of atomic hydrogen in the metal phase. This was directly supported by a) an increase in the hydrogen solution rate constant with melt surface area-volume ratio, b) a decrease in the rate constant with reduced melt stirring, and c) adherence of the initial rate of hydrogen solution to a metal-phase mass transport relation. Formerly Graduate Student, The University of Michigan This paper is based on a portion of a thesis submitted by W. M. Small in partial fulfillment of the requirements for the degree Doctor of Philosophy at The University of Michigan, 1971.     

Behavior of carbon,oxygen, and sulfur during hydrogen blowing of liquid steel

The decarburization of liquid steel during hydrogen blowing has been studied. The decarburization is caused by the interaction of carbon with oxygen dissolved in the metal. As the melt is blown with hydrogen, the decarburization is enhanced owing to hydrogen bubbles, which increase the effect of mixing of a metal bath and substantially increase the melt-gas phase interface. As a result, the rate and completeness of decarburization increase significantly. It is experimentally shown that hydrogen blowing of a melt substantially decreases the sulfur concentration in the metal because of the interaction of hydrogen with sulfur.