• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.3
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• pp.246-253
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• 2002

This paper describes the development and the field application of the ultrasonic gas flowmeter for accurate measurement of the volumetric flow rate of gases in a harsh environmental conditions in iron & steel making company. This ultrasonic flowmeter is especially suited for measuring LDG, COG, BFG gases produced in iron & steel making process. This is a transit time type ultrasonic flowmeter. We have developed the transmitting & receiving algorithm of ultrasonic wave and the ultrasonic signal processing algorithm to develope a transit time type ultrasonic flowmeter. We have evaluated the performance of ultrasonic flowmeter by the calibration system with Venturi type standard flowmeter. We has confirmed its reliability by extensive field tests for a year in POSCO, iron & steel making company. Now we have developed the commercial model of ultrasonic flowmeter and applied to the POSCO gas line.

• Journal of the Korea Society for Simulation
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• v.17 no.3
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• pp.63-73
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• 2008

The aim of study is to analyze the berth occupancy rate according to the ship size. P Iron and steel company operate exclusive bulk terminal at P port and G port and the depth of water at berth are not so equal each other. And to reduce the sea transport cost between loading port and unloading port P and G, P company increases the number of large ship while ship scheduling. But it causes to increase the berth congestion at the specific water depth berth owing to the draught of large ship. At this point, usually ship waiting time starts to rise even at low levels of berth occupancy rate, and will rise more and more sharply at the level of full utilization. But it is not common at exclusive terminal like P port and G port. Bulk ships arrive at port according to the early planned arrival time and the coefficient of variation of ship arrival time is not so big. So queueing time at exclusive terminal does not rise sharply near 80-90 berth occupancy rate.

• Resources Recycling
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• v.23 no.5
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• pp.12-20
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• 2014

Calcium ferrite is a major bonding material self-fluxed sintered ore, and it is used as a flux in the steelmaking process. Calcium ferrite is more effective binder for making sintered ore and flux for steel making because of it's low melting temperature. In this Study, calcium ferrite was made by using variety industrial by-products from steel plant. The property of calcium ferrites was investigated on the basis of test method using in the cement manufacturing process. Crystal analysis, compression test as well as thermal analysis were carried out to evaluate physical properties of calcium ferrite.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.1
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• pp.200-213
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• 2014

During the 1970s and 1980s, most of the industrial cities of the Western World went through serious de-industrialization process. While the economy of the cities declined, the cities were suffering from the lack of job opportunities, under-use of industrial infrastructure, and environmental degradation. Many of the cities attempted to tackle such problems, but very few of them have succeeded. However, the Ruhr area is showing some promising signs. This paper attempts to analyze regional revitalization policies of Dortmund, a central city of the Ruhr, and looks into the processes and outcomes of the policies. The author argues Dortmund has successfully created and set forth a new industrial path based on high-tech industries, such as information technology, micro-electromechanical systems(MEMS), logistics, and biomedical industries, away from its traditional industries, such as coal mining and steel making. Speaking from the perspective of path theory, he continues to argue that Dortmund has successfully 'locked-out' from the traditional industries, in contrast to the Grabher's argument.

• Resources Recycling
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• v.19 no.1
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• pp.21-26
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• 2010

In order to understand the microwave carbothermic reduction of steelmaking slag to recover Fe, the effects of gas atmosphere and carbon addition on the carbothermic reduction behavior of CaO-$SiO_2$-FeO slag were investigated. It was found that the maximum temperature and the reduction rate were higher in air than in nitrogen atmosphere. In addition, under air atmosphere, the maximum temperature and the reduction rate were increased by increasing the amount of additive carbon. When the carbon equivalent is 5, the maximum temperature reached as high as 1800K and the reduction rate was approximately 90%. As the Carbon equivalent increased further, the maximum temperature and the reduction rate did not change.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.84-94
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• 1996

In order to prevent shell sticking by providing sufficient lubrication between the strand and the mold, the mold oscillation has been used. Now it is well known that the shape of the oscillation curve has a decisive effect on the surface quality of the cast product. Besides, oscillation parameters such as stroke and frequency are also very important. In order to guarantee that parameters which have been found to be optimal for a certain grade of steel do not change with time, periodical checks of the physical condition of the whole equipment are necessary. The portable mold oscillation analyzer with integrated computer, developed by POSCO, records the movement of the mold in every spatial direction. The system uses the gap sensors to measure the mold movement (displacement ) in the two horizontal directions according to the mold narrow and broad faces and the vertical strokes in the four corners of mold. The gap sensor is a non-contacting minute displacement measuring device using the principle of high frequency eddy current loss. The mold oscillation diagnosis system integrates the gap sensors, their converters and the industrial portable computer with plug-in data acquisition boards. The all programs, such as the fast Fourier transformation module (amplitude and phase spectrums) and harmonic analysis module, was coded by LabVIEW$^{TM}$ software as the graphical language. In an own 'expert module' which is included in the diagnosis program, one can obtain much information about the mold oscillation equipment.

• Journal of Conservation Science
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• v.35 no.6
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• pp.631-640
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• 2019

The purpose of this study was to compare analytical results of sand iron bars reproduced by the traditional iron-making method through a destructive analysis and a non-destructive analysis. For these studies, we produced two types of samples. One was sample(SI-A), a part of the sand iron bar for destructive analysis. The other was SI-B(9 ㎠) for non-destructive analysis. A metallurgical microscope and scanning electron microscope were used for the destructive analysis, and neutron imaging analysis with the Hokkaido University Neutron Source (HUNS) at Hokkaido University, Japan, was used for the non-destructive analysis. The results obtained by destructive analysis showed that there was ferrite and pearlite of fine crystallite size, and some of these showed Widmanstätten ferrite microstructure grown within the pearlite and coarse ferrite at the edge of the specimen. The results from the neutron imaging analysis showed that there was also ferrite and pearlite with 3 ㎛ α-Fe of BCC structure. Based on these results, neutron imaging analysis is capable of identifying material characteristics without destroying the object and obtaining optimal research results when applying it to objects of cultural heritage.

• Journal of Conservation Science
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• v.31 no.4
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• pp.411-427
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• 2015

The purpose of the present study is to examine the objects excavated from the archaeological site of the Nogye Village in terms of their relationships with the iron production facilities such as 1ho smithing hearth and 2ho smelting furnace. 32 samples including slags, iron ores, and wall were analyzed to identify the mineralogical and chemical characterization. In addition, in the case of the 1ho smithing hearth slag, differing points of the cross-section were analyzed to examine its formation in depth. The analysis results suggest that the slags from the each site adjacent to the 1ho smithing hearth and 2ho furnace are related to smithing and smelting process respectively. Furthermore, it is possible to draw some conclusions that the aspects of the increased contents of nonferrous elements such as CaO in the slags in comparison with those of the iron ores are due to various factors such as charcoal ash and analytical reasons rather than an addition of CaO as flux.

• Journal of Conservation Science
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• v.33 no.2
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• pp.75-83
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• 2017

This study produced smelting slag through the reproduction of an ancient iron manufacturing technique, with the aim of facilitating a comprehensive understanding of the process by analyzing the slag components. The research suggests an interpretation method using the ratio of the subcomponents relative to the main slag components as an alternative to existing methods. We investigated the component source within the smelting furnace from which the slag is derived by developing an understanding of the tendency between slags. Based on bivariate graph and triangular coordinate data analysis, it was found that a slag can be categorized according to its components. The groups were identified as the ore slag group(centered on the ore), and the clay slag group(centered on clay and granite soil). This research determined that it is possible to estimate the components derived from the slag, depending on which group they belong to or resemble, as shown in Figure 4~7. It was found that a comprehensive understanding of the ratio between the components was more accurate than a simple analysis of the contents, for the interpretation of ancient iron manufacturing processes. This is based on the fact that a higher ratio of $TiO_2$ was detected by the components analysis, and an analysis of all the slag showed that the value of $CaO/SiO_2$ ratio was lower than 0.4, which corresponds to the reproduction experiment condition in which flux was not used.

• Journal of Conservation Science
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• v.34 no.5
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• pp.433-442
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• 2018

In this study, metal properties were compared by preparingthree iron knives from steel ingots produced via traditional iron-making, and ingot which jointed the steel of modern times. Metal microscope and SEM-EDS analysis revealed fine ferrite and pearlite structures of the hypo-eutectoid steel of Fe-C alloys. All samples also exhibited martensite on the blade of the knife. By Vicker's hardness analysis, the hardness of the sand iron knife (K1) was 533.38 HV, sand iron-nickel steel knife (K3) was 514.8 HV, and sand iron-carbon steel knife (K2) was 477.02 HV. The mass reduction due to wear was 0.058% for K1, 0.059% for K3, and 0.144% for K2. EPMA(Electron probe micro-analyzer) analysis of the surface pattern of the specimens confirmed that the patterns were exposed due to differences in the content of C or the chemical composition. Additional research on heat treatment processes is needed to increase the abrasion resistance of blades. Traditional steel ingots could produce high-quality steel if combined with nickel steel.