Exothermic ferromanganese

No chilling effect and higher recovery are the two chief advantages which have turned steel producers toward exothermic ferroalloys—a blend of an oxidizing agent, a reducing agent, and a conventional ferroalloy. The reducing and the oxidizing agents, upon contact with the molten metal, produce sufficient heat to deliver the ferroalloy in molten state. Satisfaction has been such that use of exothermic ferroalloys has greatly multiplied since exothermic ferrochrome was introduced in 1939 by the Chromium Mining & Smelting Corp.Exothermic ferromanganese has found the broadest applications of this group of alloys and was the subject of a special session at this year’s National Open Hearth Conference. Below is presented an article on production at the Electro Metallurgical Co., and three conference reports on the use of exothermic ferromanganese: at Youngstown Sheet & Tube, Bethlehem Steel, and U. S. Steel.     

铁锰多金属矿综合利用新工艺

以生物制剂KZSH01作为还原剂与铁锰多金属矿发生氧化还原反应,研究了铁锰矿的细度和还原剂的含量对还原效果的影响,考察了还原过程中温度和物相的变化,探讨了H2SO4用量对Mn和Zn浸出效果的影响.结果表明:生物还原剂KZSH01可使铁锰矿中93.0%MnO2转化为MnO,90.0?2O3转化为Fe3O4;Mn和Zn的浸出率均大于90.0%;Fe的磁选回收率大于85.0%,79.0%Pb和82.5%Ag富集在渣中.     

Oxygen refining of molten high-carbon ferromanganese

The effects of the oxygen/argon mixing ratio and temperature on the decarburization behaviour of high-carbon ferromanganese melts were investigated. The decarburization reaction was promoted and the oxidation reaction of manganese diminished by increasing temperature and decreasing the oxygen/argon mixing ratio. However, the carbon content in the melt appeared to increase during blowing at low temperatures and high oxygen/ argon mixing ratios because of faster manganese oxidation. An empirical equation was derived to predict the utilization ratio of oxygen for decarburization. The lower oxygen/argon mixing ratio and higher melt temperature were found to be essential in enhancing the efficiency of decarburization and suppressing the oxidation of manganese in the early stage of oxygen/argon refining of high-carbon ferromanganese melts.     

Manganese loss during the oxygen refining of high-carbon ferromanganese melts

Decarburization tests of high-carbon ferromanganese melts by oxygen refining were successfully carried out in a model converter with 2-ton production capacity. During the oxygen refining, the manganese loss was inherently accompanied by oxidation and evaporation. The oxidation loss of manganese into slag was affected by slag composition, melt temperature and slag weight. The oxidation loss of manganese into slag was minimum at a slag basicity of about 1.5 and it increased with temperature and slag weight. The amount of manganese evaporation loss was comparable to that of oxidation loss. An empirical equation for the evaporation loss of manganese was derived as a function of process variables. The apparent vaporization coefficient, β, was significantly affected by the oxygen mixing ratio in bottom blowing gas and the fraction of top blown oxygen.     

Evaporation behavior of low carbon ferromanganese alloy melt at reduced pressure

The distillation of an industrial Fe-Mn alloy at a high temperature and under a low pressure was suggested as an efficient method for manufacturing high purity manganese in our study. This study examined the evaporation behavior of a low carbon ferromanganese alloy melt at reduced pressure. The melt temperature, pressure, initial specific surface area of the melt and reaction time were considered as experimental variables. The evaporation ratio of manganese increased sharply in the initial reaction and remained relatively constant under various experimental conditions. The evaporation rate of manganese increased with an increasing temperature and the initial specific surface area of the melt and decreasing pressure. The activation energy of the manganese evaporation reaction decreased with a decreasing pressure. The initial specific surface area of the melt had a lesser effect than pressure. An empirical equation was derived for the rate of manganese evaporation from a low carbon ferromanganese alloy melt.     

Isothermal formation of the ε-phase after phase hardening in ferromanganese alloys

Conclusions The investigations carried out show that isothermal formation of the -phase can be controlled not only by alloying, but also by means of repeated phase transitions. Reduction of the temperature at which the formation of the -phase commences intensifies the isothermal transformation near the martensite point and at room temperature. The latter is valid if the -transformation during continuous cooling begins not lower than the temperature at which the isothermal soaking is carried out, otherwise the intensity of the isothermal process decreases, and the lower the commencement of the -transformation with respect to the temperature isothermal line, the more the intensity drops. It was found that if the -phase forms at –60, –70°C, there is a complex dependence between the rate of the isothermal process and the temperature.It was demonstrated that when the -transformation temperature is fairly low, austenite can be supercooled by rapid cooling and the -phase may form during heating. Given the same supercooling rate, the transformation of austenite into -phase during heating is more complete when the heating rate is slow.It was noticed that if in continuous cooling the -phase forms at –60, –70°C, preliminary supercooling broadens the temperature range over which the isothermal -transformation is observed. The intensity of the process is influenced by the heating rate after supercooling.It was found that the maximum amount of -phase forming in the alloy G19 during continuous cooling after repeated phase transitions and subsequent isothermal soaking does not exceed 50–55%.It was discovered that isothermal soaking at room temperature in between repeated phase transitions intensifies the stabilization of the austenite.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 2–8, April, 1965     

锰铁合金渣浸出液制备电子级硫酸锰(英文)

以锰铁合金渣为原料,经研磨、硫酸浸出后,采用中和-水解、氟化沉淀、硫化沉淀和重结晶法去除浸出液中的铁、铝、钙、镁和重金属以及钠、钾等离子以制备电子级硫酸锰。研究反应pH、反应温度和不同添加剂的用量对硫酸锰产品中杂质含量的影响,并得到了较优的温度、pH、沉淀剂的用量等工艺条件。结果表明:在较优工艺条件下,所制备的碳酸锰中,Ca2+、Mg2+、Na+、K+杂质离子的含量小于0.005%,Fe3+、Al3+和重金属离子的含量小于0.001%,Mn2+的含量大于32%,硫酸锰产品的质量满足锂离子电池正极材料的要求。     

The method of production of damask steel

The Russian term is "bulat" steel and to bulat is related the understanding of steel with high elastic and cutting properties, for which a unique microstructure, a patterned surface, is characteristic. To it was imparted special value and it was assumed to be a compulsory component of damask steel. The word "bulat" is of Iranian origin (pulad).In the modern understanding steel is a material with a certain chemical composition and damask steel does not fit under it.     

The production of large structural titanium castings

Titanium-alloy castings have recently become an attractive option for critical-structural applications in aerospace structures. These opportunities have occurred primarily because of the development of advanced-process technologies, such as rapid-prototyping methodology and solidification modeling, which have dramatically reduced the cost and time required to obtain first-article castings through concurrent engineering. Moreover, these technologies have lowered the risk involved in examining new applications for titanium castings. This article examines the implementation of these new technologies and the heat treatment and mechanical properties of large structural castings, particularly in relation to section size. Additionally, the production of a cast-titanium transmission adapter for the V-22 Osprey Tiltrotoraircraft is described. Editor’s Note: Although JOM typically employs metric units only, this article features U.S. customary units as a reflection of the industry standards described. J. Klepeisz earned his B.S. in metallurgical engineering at the University of Illinois in 1984. He is currently plant manager of structural business operations at Howmet Hampton Casting. S. Veeck earned his B.S. in metallurgical engineering at the University of Illinois in 1963. He is currently senior staff engineer at Howmet Research Corporation.     

The optimization of material flow in production

Market demands are different: they tend to require individual, customized products of high reliability and high quality and also produced in right time. Material flow optimization is an indispensable step to be taken. The proposed optimization method is material flow analysis, which is giving an insight of the production organization of a company and its evaluation at different organizational levels. The analysis is based on a technological database and on the organization of individual departments of a company. It enables a material and information flow analysis as well as an analysis of the department and machines layout respectively. The result of the analysis is material flow rationalization, thus minimizing production costs.     

The production of high-purity aluminum in Japan

The two most widely industrialized techniques for aluminum refining are the three-layer electrolytic refining process and the segregation process. The three-layer process uses molten salt electrolysis to produce aluminum of greater than 99.99% purity. The segregation process produces aluminum of 99.98–99.99% purity. Although aluminum refined by the segregation process has a somewhat lower purity than that produced by the other methods, the segregation process has become increasing common since it consumes less energy. Ultrahigh-purity aluminum (99.9999%), which has uranium and thorium impurities reduced to less than 1 ppb, can also be produced.     

The high-volume production of heterojunction bipolar transistors

The insertion of advanced microwave devices into high-volume applications is critically dependent upon a robust and reproducible epitaxial growth technology accompanied with a reproducible process technology. The precise control of the material and device parameters is essential to maintain a high-yield process, which leads to a low-cost product. Although AlGaAs/GaAs heterojunction bipolar transistors have been widely demonstrated in many company research laboratories and universities, the transition from a laboratory environment to high-volume production requires a thorough understanding of the metalorganic chemical vapor deposition growth process and its correlation with device performance. In this work, high-performance AlGaAs/GaAs heterojunction bipolar transistors grown by MOCVD with excellent control in the device parameter tolerances have been demonstrated in very high volumes. N. Pan earned his Ph.D. in electrical engineering at the University of Illinois in 1988. He is currently chief scientist at Kopin Corporation. Dr. Pan is a member of TMS. D. Hill earned his M.S. in materials science at the Polytechnic Institute of New York in 1986. He is currently vice president of epioperations at Kopin Corporation. Mr. Hill is also member of TMS. C. Rose earned his M.S. in advanced manufacturing engineering at Worcester Polytechnic Institute in 1990. He is currently a quality assurance engineer at Kopin Corporation. R. McCullough earned his A.S. in mechanical design engineering at Wentworth Institute of Technology in 1970. He is currently engineering manager at Kopin Corporation. P. Rice earned his BSEET in electrical engineering at Wentworth Institute of Technology in 1990. He is currently a characterization engineer at Kopin Corporation. D.P. Vu earned his Ph.D. in solid-state physics at Louis Pasteur Institute in 1983. He is currently a principal scientist at Kopin Corporation. K. Hong earned his Ph.D. in electrical engineering at the University of Michigan in 1996. He is currently an electronic design engineer at Rockwell Semiconductor Systems. C. Farley earned his Ph.D. in engineering at the University of Texas at Austin in 1986. He is currently manager, advanced device technology, at Rockwell Semiconductor Systems.     

厚板生产技术的发展

综述了厚板轧机的发展及其技术改造的特点;介绍了厚板生产TMCP技术的控制环节,立辊轧机的应用以及卷轧中板的生产工艺特点。     

The production of ultrahigh-purity copper for advanced applications

Ultrahigh-purity copper (UHPC) of five to seven nines has been developed, and commercial production has been started by Nippon Mining and Metals Company. This value-added copper has such characteristics as high electrical and thermal conductivity at very low temperatures, low softening temperatures, and high workability due to fewer nonmetallic inclusions and voids as compared with conventional high-purity copper (i.e., four nines). Taking advantages of these characteristics, UHPC is being applied to bonding wire of integrated circuits and cables for audio devices.     

马钢火车轮生产系统技术改造

分析了马钢车轮轮箍厂在车轮生产中存在的主要问题,介绍了车轮生产工艺及设备的改造情况。改造后取得了能生产高质量、高精度、高速重载火车轮的显著成果。     

半连续式小型车间工艺改造

介绍了通钢辉南轧钢厂半连续式小型车间“一火成材”技术改造前后的主要设备、生产工艺及改造后的效果。