• Journal of the Korean Society for Heat Treatment
• /
• v.25 no.4
• /
• pp.181-189
• /
• 2012

The demand on quantitative measurement of the heat flux is motivated in making higher-quality steel product through a water quenching process of plate mill. To improve a spatial degree of heat flux measurement, the multi-point heat flux measurement was carried out by a unique experimental technique that has a combination of the existing single-point heat flux gauge. The corresponding heat flux can be easily determined by Fourier's law in a conventional way. The multi-point heat flux gauge developed in this study can be applicable to measure the surface heat flux, the surface heat transfer coefficient during a water quenching applications of steelmaking process. The results exhibit different heat transfer regimes; such as single-phase forced convection, nucleate boiling, and film boiling, that are occurred in close proximity on the multi-point heat flux gauge quenched by water impinging jet.

• Resources Recycling
• /
• v.23 no.5
• /
• pp.12-20
• /
• 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 Korea Foundry Society
• /
• v.24 no.1
• /
• pp.26-33
• /
• 2004

The pressure of the mold flux acting on the meniscus shell was investigated through the coupling analysis of heat transfer in the mold and fluid flow in the flux caused by the mold oscillation. Finite element method was employed to solve the conservation equation associated with appropriate boundary conditions. As reported by previous workers, the axial pressure is positive on the negative strip time and negative on the positive strip time. A maximum pressure is predicted toward the top of the meniscus shell which has the thin shell arid a maximum value is in proportion to the relative mold oscillation velocity. The relative mold oscillation velocity was changed by the effect of meniscus level fluctuation. Therefore the pressure of the mold flux acting on the meniscus shell was different each cycle of the mold oscillation due to the irregularity of relative mold oscillation velocity.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.25 no.4
• /
• pp.287-292
• /
• 2012

In this study, Multi-Channel Magnetic Flux Leakage(MFL) sensor - based inspection system was applied to monitor the condition of cables. This inspection system measures magnetic flux to detect the local faults(LF) of steel cable. To verify the feasibility of the proposed damage detection technique, an 8-channel MFL sensor head prototype was designed and fabricated. A steel cable bunch specimen with several types of damage was fabricated and scanned by the MFL sensor head to measure the magnetic flux density of the specimen. To interpret the condition of the steel cable, magnetic flux signals were used to determine the locations of the flaws and the level of damage. Measured signals from the damaged specimen were compared with thresholds set for objective decision making. In addition, the magnetic flux density values measured from every channel were summed to focus on the detection of axial location. And, sum of flux density were displayed with threshold. Finally, the results were compared with information on actual inflicted damages to confirm the accuracy and effectiveness of the proposed cable monitoring method.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.7
• /
• pp.1-7
• /
• 2021

Restrictions on the emissions of nitrogen oxides, sulfur oxides, carbon dioxide, and particulate matter from marine engines are being tightened. Each of these emissions requires different reduction technologies, which are costly and require many pieces of equipment to meet the requirements. Liquefied natural gas (LNG) fuel has a great advantage in reducing harmful emissions emitted from ships. Therefore, the marine engine application of LNG fuel is significantly increasing in new ship buildings. Accordingly, this study analyzed the internal support structure, insulation type, and fuel supply piping system of a 35 m3 International Maritime Organization C type pressurized storage tank of an LNG-fueled ship. Analysis of the heat transfer characteristics revealed that A304L stainless steel has a lower heat flux than A553 nickel steel, but the effect is not significant. The heat flux of pearlite insulation is much lower than that of vacuum insulation. Moreover, the analysis results of the constraint method of the support ring showed no significant difference. A553 steel containing 9% nickel has a higher strength and lower coefficient of thermal expansion than A304L, making it a suitable material for cryogenic containers.

• Journal of Conservation Science
• /
• v.30 no.4
• /
• pp.335-343
• /
• 2014

This study classified the result of non-metallic inclusion analysis and result of microstructure investigation on the ironware excavated in the Baekje region into Han River, Geum River, and Yeongsan River to estimate the iron making temperature and study the characteristics of regional and temporal characteristics of the heat treatment technology and steel making technology. Regardless of era, bloom iron and sponge iron are judged to be the major method for making as a directreduction process in all three regions. The result of the reinterpretation of the non-metallic inclusion by the oxide ternary constitutional diagram suggest that the temperature inside of the furnace is estimated to be between $1,100{\sim}1,300^{\circ}C$ while making the steel. The magnetic iron ores are the major raw material of steel ore and irons with high $TiO_2$ are estimated to use iron sands. Ironware with $CaO/SiO_2$ rate higher than 0.4% are considered to have artificially added the flux of calcareous materials. It was found that the iron making method is the solid caburizing-steel which caburizes low-carbon steels by the CO gas and $CO_2$ gas created when heating the forging furnace with charcoal. Also, the ironware manufacturers in the Baekje during 3rd century recognized the heat treatment technology as they performed carburizing process and quenching to intentionally increase the strength of necessary parts.

• Resources Recycling
• /
• v.23 no.5
• /
• pp.3-11
• /
• 2014

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 calcinating method in the cement manufacturing process in order to reduce manufacturing costs and increase productivity. Limestone and calcination sludge were used as CaO source, steelmaking sludge, blast furnace dust and iron ore were used as Fe-bearing raw materials. The sintering temperature of specimens is in the range of $950{\sim}1170^{\circ}C$. For Calcium ferrite can be used 'binder for making sintered ore' or 'flux for converter/electric furnace' with a low melting point properties, the raw material characteristics and sintering properties were investigated.

• Resources Recycling
• /
• v.30 no.6
• /
• pp.53-60
• /
• 2021

In EAF steelmaking industries, MgO content in slag increases due to the addition of dolomite flux to protect refractory lines of furnaces and improve the desulfurization capability of slag. In addition, coal powder is injected in the molten steel bath to increase the energy efficiency of the process. In this regard, the utilization of waste MgO-C refractory material as a flux was examined because it has high amounts of MgO (>70%) and graphite carbon (>10%). A series of experiments were carried out using industrial EAF slag with added light burnt dolomite and waste MgO refractory material from a Korean steel company. The results for the addition of the two fluxes were similar in terms of slag basicity; therefore, it is expected that waste MgO-C refractory material can successfully replace dolomite flux. In addition, when the waste MgO-C refractory material was added as flux, slag foaming phenomenon was demonstrated because of the reaction between the graphite from the refractory material and iron oxides in the slag.

• Journal of Conservation Science
• /
• v.28 no.4
• /
• pp.367-376
• /
• 2012

The ironware production technology is a measure to fathom the society's level of development in time. To understand iron-manufacure methods in the past, various investigations on the fine structures and additions of ironware remains and Iron ingot have been conducted in a way of natural science. This study metallurgically reclassifies remains excavated in iron-manufacture remains located in Beokje, Goyang, which are thought to be in time of Goryeo Dynasty, and draws an inference from the element analysis on the iron-manufacture and smelting technology. Iron ingot samples with a cast iron structure are divided into those with a white cast iron structure and those with a grey cast iron rich in P. The P content of grey cast iron appeared to be the result of adding a flux agent like lime, iron ingot and carbon steel iron ingot with a cast iron structure excavated in the area is regarded as pig iron which was made without a refining process. In this study it seems that two methods of making ironware were used in the area; one is the method of making ironware by pouring cast iron to the casting, and the other is the method of making carbon steel through the refinement of pig iron. It appears that highly even steel structure of carbon steel and a small amount of MnS inclusion are very similar with that of the modern steel to which Mn is artificially added. Nevertheless, these data alone cannot be used to determine the source of Mn in the carbon steel of the excavated from the iron-manufacture remains, which raises the need for further studies on the source and the possibility of carbon steel via the iron-manufacture process of cast iron.

• Resources Recycling
• /
• v.24 no.3
• /
• pp.34-43
• /
• 2015

Raw materials in steel industry decide on the productivity, quality and price competitiveness. Utilizing iron-containing by-products as raw materials for steel products can save the cost of cleaning up iron-containing by-products and solve environmental issues. Iron-containing by-products have a small particle size. If they are directly inserted in a steel making process, it cause a problem such as poor heat flow and scattering. To solve these problems and induce the additional reduction, study concern with iron ore-coal mixed briquette technique are conducted by many researchers. In this paper, method of making carbon composite briquette iron(CCBI) using iron-containing by-products was studied. The effect of composition of Fe-containing process wastes, reducing agent, flux and binder on formability of CCBI (carbon composite briquette iron) was measured.