• Journal of the Korean Chemical Society
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• v.37 no.10
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• pp.861-866
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• 1993

In general, the concentration of constituents can be more accurately measured in x-ray fluorescence analysis of Fe-Ni-Cr alloy by reducing and correcting the matrix effect with standard ingot samples. Because of the difficult the treatment at a high temperature in preparing the ingot samples of various concentrations, several standard specimens were prepared by mixing the powders of the metallic oxides in certain proportions and pressing them with a costant pressure. With the metallic oxide specimens thus obtained, different matrix coefficients were calculate from the intensities of the strength of the x-ray fluorescence and the concentration of the substances. It is found that effects of Fe and Cr on Ni are absorption rich and effects of Fe and Ni on Cr are enhancement rich, whereas Ni enhances Fe Fluorescence but Cr absorves Fe K${\alpha}$ line. And the x-ray fluorescence intensities were compared and analyzed between the metallic oxides and the ingot samples.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.907-911
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• 2012

High purity silicon can be obtained from Al-Si alloys by a combination of solvent refining and centrifugation. Silicon purification by crystallization of silicon from an Al-Si alloy melt was carried out using 2N and 4N purity aluminum and 2N purity silicon as raw materials. The effect of the purity of raw materials on the final silicon ingot purity by centrifugation was investigated for an Al-50 wt% Si alloy. Alloys were melted using an electrical resistance furnace, and then poured into a centrifuging apparatus. A silicon lump like foam was obtained after centrifugation and was leached by an acid in order to get pure silicon flakes. Then silicon flakes were melted to make a silicon ingot using an induction furnace. The purities of the silicon flakes and silicon ingot were enhanced significantly compared to those of the raw materials of silicon and aluminum. The silicon ingot made of 4N aluminum and 2N silicon showed the lowest impurities.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.819-823
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• 1996

In the large steel ingosts, void defects exhibiting microvoid shapes are inevitably formed in the V-segregation zone of the ingots during solidification. In the hot open-die forging process, material properties are improved by eliminating internal porosity. The void size is practically very small as compared with the huge large ingot. Thus, for deformation analysis of a large ingot, a massive number of elements are needed in order to describe a void surface and to uniform mesh sturcture. In the present work the Global/Local scheme has been introduced in order to reduce the computational time and to easily generate the mesh system as a void module of local mesh for obtaining the accurate solution around a void. The procedure of the global- local method consists of two steps. In the first step global analysis is carried out which seeks a reasonably good solution with a cpurse mesh system without describing a void. Then, a local analysis is performed locally with a fine mesh system under the size-criterion of a local region. The computational time has been greatly reduced. Though the work it has been shown that large ingot forging incorporation small voids can be effectively analyzed by using the proposed Global/Local scheme.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.8-13
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• 2012

Ti-3Al-2.5V ingot was produced, processed into a titanium alloy wire of 9mm diameter, and the characteristics were studied in comparison with imported material. The ingot satisfied ASTM Grade 9 standard showing oxygen content of 0.11wt% and iron content of 0.085wt%. The hardness of the 9mm diameter titanium alloy was similar to that of the imported material showing values between 225 and 250Hv, and the tensile strength of the imported material was 804MPa while that of the domestic development was 734MPa. The elongation of the imported material was 12% while that of the domestic development was 22%. A new process of manufacturing 9.0mm diameter titanium alloy wire through forging and multi-step hot rolling process out of 400mm diameter ingot was developed.

• Korean Journal of Materials Research
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• v.13 no.9
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• pp.619-624
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• 2003

This paper describes a method to control Mn and Fe contents in recycled AZ91D ingots, based on the mutual solubility of Mn and Fe in AZ91 alloy melts. For this purpose, Fe solubility with the change of Mn content and temperature was investigated in the homogenized and re-precipitated liquid AZ91 alloy. The increase of the amount of Mn added to the melt resulted in the decrease of Fe content. The data obtained in this study was adopted to the pilot plant for recycling of the scrap. As a result, Mn and Fe contents measured in the recycled ingot were in good agreement with ASTM B93 standard.

• Journal of Magnetics
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• v.13 no.3
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• pp.102-105
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• 2008

This study examined the feasibility of the combining HDDR-process (hydrogenation, disproportionation, desorption and recombination) with mechanical milling to prepare single domain $Nd_2Fe_{14}B$ particles from a Nd-Fe-B alloy ingot. The $Nd_{15}Fe_{77}B_8$ alloy was HDDR-treated and then subjected to a roller-milling. In the HDDR-treated $Nd_{15}Fe_{77}B_8$ alloy, very small $Nd_2Fe_{14}B$ grains comparable to their critical single domain size(0.3 ${\mu}m$) were observed. These fine individual grains were separated successfully along the grain boundaries by a roller-milling. The separated $Nd_2Fe_{14}B$ grains were found to be single domain particles. These results suggest that single domain particles of the $Nd_2Fe_{14}B$ phase can be prepared from a Nd-Fe-B ingot alloy by combining a HDDR-process with mechanical milling.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.05a
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• pp.56-60
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• 2006

In 2005, the imports of titanium metals was about 22.8 million US$(7,700 tons) in Korea. New scrap produced was estimated to be 359 tons and the exports were about 352 tons. Generally scrap is recylced into titanium ingot either with or without virgin metal using traditional vacuum-arc-melting and cold hearth melting. In Korea, there is no titanium ingot producers(recyclers). In this paper, the brief summary of major titanium melting technology, such as vacuum arc remelting(VAR), electron beam melting(EBM), plasma arc melting(PAM) is given and discussed. In view of titanium market situation of Korea, the technological development of ingot production from scrap is big problem to be solved in order to realize extensive cost reduction for titanium products.

• Nuclear Engineering and Technology
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• v.38 no.7
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• pp.675-680
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• 2006

The neutron transmutation doping of silicon (NTD), as a method to produce a high quality semiconductor, utilizes the transmutation of a silicon element into phosphorus by neutron absorption in a silicon single crystal. In this paper, we present the design of a neutron screen for a 6' Si ingot irradiation in the NTD2 hole of HANARO. The goal of the design is to achieve an even flat axial distribution of the resistivity, or $Si^{30}(n,{\gamma})Si^{31}$ reaction rate, in the irradiated Si ingot. We used the MCNP4C code to simulate the neutron screen and to calculate the reaction rate distribution in the Si ingot. The fluctuations in the axial distribution were estimated to be within ${\pm}2.0%$ from the average for the final neutron screen design; thus, they satisfy the customers' requirement for uniform irradiation. On the other hand, we determined the optimal insertion depths of the Si ingots by varying the critical control rod position, which greatly affects the axial flux distribution.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.815-819
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• 2018

In this study, criticality safety assessments of the potential for storing transuranic element (TRU) ingots via a pyroprocess were evaluated to determine the appropriate TRU storage design parameters, in this case the ratio of the TRU ingot height to the radius and the number of TRU ingot canisters stacked within a container. Various accident situations were modeled over a modeling period of 5 years for a cumulative inventory of TRU ingots with various water densities in submerged containers and with various pitches between the containers in the facility. Under these combinations, we calculated the threshold of TRU height and radius ratio depending on the number of canisters in a container to keep the stored TRU in a subcritical state. The ratio of the TRU ingot height to radius should not exceed 4.5, 1.1, 0.5, 0.3, and 0.2 for two, three, four, five, and six levels of stacked canisters in a container, respectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.67-70
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• 2008

This paper deals with the effect of radial parameters in cogging process such as reduction in height (Rh) and rotational angle ($\theta$) of a billet on a void closure for large forged products. Usually closing and consolidation of internal void defects in a ingot is a vital matter when utilized as large forged products, using a press with limited capacity and the sizes of the ingots becoming larger. Consequently, it is important to develop cogging process for improvement of internal soundness without a void defect and cost reduction by solid forging alone with limited press capacity. For experiments of cogging process, hydraulic press with a capacity of 800 ton was used together with a small manipulator which was made for rotation and overlapping of a billet. Size of a void was categorized into two types; $\emptyset$ 6.0 mm and $\emptyset$ 9.0 mm to investigate the change of closing and consolidation of void defects existed in the large ingot during the cogging process. Also open void and closed void in the ingot were tackled to show the differentiation of closing process of internal voids with respect to void sizes. In this paper systematic configuration for closing process of void defects were expressed based on this experiment results in the cogging process.