• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.4-23
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• 2020

The purpose of this study was to explore the diversity of Korea's iron casting technology and to examine various casting methods. The study involved a literature review, analysis of artifacts, local investigation of production tools and technology, and scientific analysis of casting and cast materials. Bellows technology, or Bulmi technology, is a form of iron casting technology that uses bellows to melt cast iron before the molten iron is poured into a clay cast. This technology, handed down only in Jeju Island, relies on use of a clay cast instead of the sand cast that is more common in mainland Korea. Casting methods for cast iron pots can be broadly divided into two: sand mold casting and porcelain casting. The former uses a sand cast made from mixing seokbire (clay mixed with soft stones), sand and clay, while the latter uses a clay cast, formed by mixing clay with rice straw and reed. The five steps in the sand mold casting method for iron pot are cast making, filling, melting iron into molten iron, pouring the molten iron into the cast mold, and refining the final product. The six steps in the porcelain clay casting method are cast making, cast firing, spreading jilmeok, melting iron into molten iron, pouring the molten iron, and refining the final product. The two casting methods differ in terms of materials, cast firing, and spreading of jilmeok. This study provided insight into Korea's unique iron casting technology by examining the scientific principles behind the materials and tools used in each stage of iron pot casting: collecting and kneading mud, producing a cast, biscuit firing, hwajeokmosal (building sand on the heated cast) and spreading jilmeok, drying and biyaljil (spreading jilmeok evenly on the cast), hapjang (combining two half-sized casts to make one complete cast), producing a smelting furnace, roasting twice, smelting, pouring molten iron into a cast, and refining the final product. Scientific analysis of the final product and materials involved in porcelain clay casting showed that the main components were mud and sand (SiO₂, Al₂O₃, and Fe₂O₃). The release agent was found to be graphite, containing SiO₂, Al₂O₃, Fe₂O₃, and K₂O. The completed cast iron pot had the structure of white cast iron, comprised of cementite (Fe₃C) and pearlite (a layered structure of ferrite and cementite).

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

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.77-84
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• 2000

In this paper, the stress analysis of the cast iron insert of spent nuclear fuel disposal canister in a deep repository at 500m underground is done for the underground pressure variation. Since the nuclear fuel disposal usually emits much heat and radiation, its careful treatment is required. And so a long term safe repository at a deep bedrock is used. Under this situation, the canister experiences some mechanical external loads such as hydrostatic pressue of underground water, swelling pressure of bentonite, sudden rock movement etc.. Hence, the canister should be designed to withstand these loads. The cast iron insert of the canister mainly supports these loads. Therefore, the stress analysis of the cast iron insert is done to determine the design variables such as the diameter versus length of canister and the number and array type of inner baskets in this paper, The linear static structural analysis is done using the finite element analysis method. And the finite element analysis code, NISA, is used for the computation.

• Smart Structures and Systems
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• v.7 no.4
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• pp.241-262
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• 2011

Cast iron pipe has been used as a water distribution technology in North America since the early nineteenth century. The first cast iron pipes were made of grey cast iron which was succeeded by ductile iron as a pipe material in the 1940s. These different iron alloys have significantly different microstructures which give rise to distinct mechanical properties. Insight into the non-destructive structural condition assessment of aging pipes can be advantageous in developing mitigation strategies for pipe failures. This paper examines the relationship between the small-strain and large-strain properties of exhumed cast iron water pipes. Nondestructive and destructive testing programs were performed on eight pipes varying in age from 40 to 130 years. The experimental program included microstructure evaluation and ultrasonic, tensile, and flexural testing. New applications of frequency domain analysis techniques including Fourier and wavelet transforms of ultrasonic pulse velocity measurements are presented. A low correlation between wave propagation and large-strain measurements was observed. However, the wave velocities were consistently different between ductile and grey cast iron pipes (14% to 18% difference); the ductile iron pipes showed the smaller variation in wave velocities. Thus, the variation of elastic properties for ductile iron was not enough to define a linear correlation because all the measurements were practically concentrated in single cluster of points. The cross-sectional areas of the specimens tested varied as a result of minor manufacturing defects and levels of corrosion. These variations affect the large strain testing results; but, surface defects have limited effect on wave velocities and may also contribute to the low correlations observed. Lamb waves are typically not considered in the evaluation of ultrasonic pulse velocity. However, Lamb waves were found to contribute significantly to the frequency content of the ultrasonic signals possibly resulting in the poor correlations observed. Therefore, correlations between wave velocities and large strain properties obtained using specimens manufactured in the laboratory must be used with caution in the condition assessment of aged water pipes especially for grey cast iron pipes.

• Analytical Science and Technology
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• v.6 no.3
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• pp.297-305
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• 1993

Generally, it is difficult to analyze cast iron samples with spark discharge emission spectrometry since the content of carbon in these samples is high as a few percent. The cast iron samples were analyzed with the developed glow discharge emission spectrometer composed of glow discharge emission source and polychromator. The discharge condition of glow discharge lamp(GDL) has been optimized by variation of Ar gas pressure, discharge voltage and discharge time. Under the optimum conditions obtained in this work, relationships between the measured emission intensities and concentration of two types of cast iron standard samples(BAS, LECO) were investigated. Most of elements(Mn, Si, P, S etc.) showed the good linearity in one calibration curve. And the carbon showed slightly the systematic difference according to the type of standard samples.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.155-161
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• 2012

It was attempted to evaluate the microstructure and quality of various types of cast iron by ultrasonic velocity measurement. Three types of commercial gray cast iron and ductile cast iron were used for this investigation, respectively. One type of the ductile cast iron was heat-treated as a function of annealing time to produce different microstructure. Ultrasonic velocity measurement, microstructural analysis (pearlite area fraction, graphite length and nodularity), and hardness measurement were performed to find empirical correlations among these parameters. Ultrasonic velocity of ductile cast iron was markedly faster than that of gray cast iron. Ultrasonic velocity decreased with the decrease of fraction of pearlite structure. As a quality monitoring parameter of cast iron, potential of ultrasonic velocity was suggested.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.76-82
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• 2017

The cylinder liner of a diesel engine is commonly made of gray cast iron. However, this cylinder liner can be damaged by the cavitation phenomenon in wet conditions. This cavitation has remained an unsolved problem until now. In this study, the cause of cavitation corrosion due to antifreeze solution was examined using a scanning electron microscope (SEM) and a 3D microscope. The necessary data to prevent the damage caused by cavitation erosion and the corrosion of gray cast iron cylinder liner was obtained. Analysis determined that the gray iron structure consists of an ${\alpha}-matrix$, flake graphite, and steadite. Cavitation erosion was initiated in the coarse flake graphite and propagated into the steadite with pitting. Under repetitive reaction conditions, the ${\alpha}-matrix$ was partially separated from the gray cast iron. This study is expected to be used as the basic data for the prevention of gray cast iron cavitation erosion and corrosion by controlling the graphite and steadite phases.

• Corrosion Science and Technology
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• v.20 no.3
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• pp.143-151
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• 2021

In this study, optimal shot peening process conditions were investigated for improving the cavitation erosion resistance of gray cast iron under a marine environment. Shot peening was performed with variables of injection pressure and injection time. The durability was then evaluated through cavitation erosion test which was conducted according to the modified ASTM G-32 standard. The tendency of cavitation erosion damage according to shot peening process condition was investigated through weight loss rate, surface and cross-sectional analysis of the specimen before and after the test. As a result, the shot peening process condition that could minimize cavitation erosion was when the injection pressure was the lowest and when the injection time was the shortest. This was because the flake graphite exposed on the gray cast iron surface could be easily removed under such condition. Therefore, the notch effect can be prevented by surface modification. In addition, the cavitation erosion damage mechanism of gray cast iron was discussed in detail.

• Journal of Korea Foundry Society
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• v.21 no.3
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• pp.198-203
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• 2001

In determining properties of ductile cast iron, it is well known that nodularity plays a significant role. Therefore, the national and/or international standards for ductile cast iron such as KS, ISO, ASTM and JIS have specified some methods for evaluating it. However, most of standards have not recommended the methods using image analyzer which is known as an objective analyzing tool for evaluating microstructure. In this study, a reliable method for evaluating nodularity by image analyzing method was proposed, and the result was compared with that from the common counting method proposed in KS D 4302-1999. It was found that there was a reasonable relationship in nodularities measured by these two methods.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.3
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• pp.33-37
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• 2009

Manifold could apply stainless steel with light weight and durability to improve fuel efficiency at automotive industry. This study is analyzed and compared by heat transfer and deformation according to the materials of cast iron and stainless steel. The heat transfer at manifold of cast iron at the distribution of heat temperature is more than that of stainless steel. But the value of maximum heat deformation in case of stainless steel is 1.5 times as great as that in case of cast iron. The value of maximum heat equivalent stress in case of stainless steel is 2.7 times as great as that in case of cast iron. This maximum stress at manifold is shown at the part assembled with engine body.