• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 가을 학술발표회 논문집
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• pp.240-247
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• 1994

The purpose of this study is to examine the raising of strength of concrete and workability using casting foundry fly ash. First, we conducted analysis of chemical components of fly ash. Then, we tested uniaxial strength of concrete at ages of 3, 7, and 28 days. As a result, we found that the strength of concrete using casting foundry fly ash is raisen up 16% than plain concrete when the fly ash is added 0.6% of weight of cement.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 추계학술발표대회 개요집
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• pp.207-209
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• 2003

In FE analysis for residual stress of a casting, contact force between mould and casting material and gravity force must be considered for exact simulation. Preheating of a repair weldment had a little effects on the reduction of residual stress. However, preheating with hammer peening had a great deal of effects on the reduction of residual stress. A method for estimation of fatigue life for a repair weldment has been established.

• 한국주조공학회지
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• 제30권3호
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• pp.100-110
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• 2010

The solidification sequence and formation of intermetallic phase of Fe-rich Al-Si-Cu alloy were investigated by using real-time imaging of synchrotron X-ray radiation. Effects of cooling rate during uni-directional solidification on the resultant solidification behavior was also studied in a specially constructed vacuum chamber in the SPring-8 facility. The series of radiographic images were complementarily analyzed with conventional analysis of OM and SEM/EDX for phase identification. Detailed solidification sequence and formation mechanisms of various phases were discussed based on real-time image analysis. The growth rates of $\alpha$-AlFeMnSi and ${\beta}-Al_5FeSi$ were measured in order to understand the growth behavior of each phase. It is suggested that real-time imaging technique can be a powerful tool for the precise understanding of solidification behavior of various industrial materials.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.786-789
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• 2005

The proper parameters in a twin roll strip casting are important to obtain the stabilization of the Mg sheet. What is examined in this paper is the quantitative relationships of the important control parameters such as the roll speed, height of pool region, outlet size of nozzle, solidification profile and the final point of solidification in a twin roll strip casting Unsteady conservation equations were used for transport phenomena in the pool region of a twin roll strip casting in order to predict a velocity, temperature distributions of fields and a solidification process of molten magnesium. The energy equation of cooling roll Is solved simultaneously with the conservation equations of molten magnesium In order to consider the heat transfer through the cooling roil. The finite difference method (2-D) and the finite element method (2-D) are used in the analysis of pool region and cooling roil to reduce computing time and to improve the accuracy of calculation respectively.

• 한국산업융합학회 논문집
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• 제9권2호
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• pp.141-145
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• 2006

In case of sense case manufactured by method of outage capacity, sensitivity is declined by outside effect and method of the photo electricity has a problem in transmission. therefore, packing case of composite sense should be developed to improve such a problem about influence of outside environment and its property evaluation has been performed. Mechanical property and result of analysis & test evaluation of Mat'l on aluminum die-casting(ADC 12type) Mat'l developed are as following. Tensile test piece, No. 4 of KS B 0801, has been applied to mechanical property test of Mat'l and It has been tested by method of metal mat'l tensile test(KS B 0802 : 2003). It can be found that physical property to KS(Korea Standard) is excellent. and homogeneous mechanical property appears. Test of Mat'l analysis has been performed by using OE Spectrometer, according to ASTM E 1251 : 1994 regulation. Consequently, good and homogeneous component contents classified by element to standard, except for Fe, have been obtained with coordination of Fe content as below 1.3% from composition standard of Aluminum Die-casting.

• 한국산업융합학회 논문집
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• 제22권3호
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• pp.337-351
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• 2019

We Proposed a new technology to develop vertical type multi-joint robot system enable to adapt in high temperature environment. The main contents is a new approach to design a vertical type articulated robot with prismatic joint and analysis of thermal for process automation of casting and forging. The proposed robot is suitable to use handling working parts of casting and forging. for the manufacturing process of forging and casting. The reliability is illustrated that the proposed technique is more stable and robust than the conventional system. This study is concerned with an analytical methodology of kinematic computation for 7 DOF manipulators for optimization of forging manufacturing process.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2364-2369
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• 2015

본 논문에서는 고정밀 로터용 원심주조기 방식을 연구 및 개발함으로써 관련 업종의 생산성 향상을 위하여 로터의 충진율 해석을 통해 RPM에 따른 로터의 충진율을 비교해 최적의 RPM을 제시하였다. 회전속도가 600 rpm일 때 충진율 99.47%를 보여줌으로써 실제 작업현장에서의 결과와 비슷하므로 이를 토대로 추가적으로 수행하여 그 결과를 이용한다면 보다 정확한 공정설계를 할 수 있을 것으로 사료된다. 또한 소형 레이들의 전도율해석을 통하여 고품질의 주조제품이 생산될 수 있도록 적합한 소형 레이들의 온도를 분석하였다. 니크롬선을 이용한 가열장치가 없는 경우는 $427^{\circ}C$까지 급격히 떨어진 상태로 알루미늄용액이 급격히 굳어지기 시작했다. 그러나 니크롬선의 가열장치가 있는 경우에는 알루미늄 용액의 용융온도인 $660^{\circ}C$이상을 유지한 상태에서 작업을 할 수 있었으며 온도변화가 거의 없음을 알 수 있었다.

• 대한기계학회논문집A
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• 제25권9호
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• pp.1438-1443
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• 2001

The significance of the casting/forging process for reducing the production cost of large components is being noted in these days. This casting/forging process is a method of forging a workpiece preformed by casting into the final shape. In this study, the casting/forging process has been applied in manufacturing a large aluminum flange in order to reduce press capacity and material cost. Firstly, a hot compression test was performed with cast cylindrical billets in order to determine the optimum forging condition of the aluminum flange. The optimum range of forging temperature of Al 5083 was from 420$\^{C}$ to 450$\^{C}$. The suitable strain rate was 1.5 sec(sup)-1. The deformation amount of a preform of a preform in a forging process is a key role in the mechanical properties of casting/forging products. In order to find the change of mechanical properties according to effective stain of cast aluminum billets, a hot upsetting test were performed with rectangular blocks and then a uniaxial tensile test was performed with specimens cut from the upsetted billets. The tensile strength and the elongation of cast/upsetted aluminum billets were increased largely until the effective strain was 0.7. FE analysis was performed to determine the configurations of case preform and die for an aluminum flange. In the FE analysis, the forging load-limit was fixed 1500ton for low equipment cost. The cast preform was designed so that the effective stain around the neck of a flange exceeded 0.7. From the result of FE analysis, optimal configurations of the cast preform and the die were designed for a large flange. The filling and solidification analysis for a sound cast-preform was carried out with MAGMA soft. In the forging experiment for an aluminum flange, it was confirmed that the optimal configuration of the cast preform predicted by FE analysis was very useful. The cast/forged products using designed preform were made perfectly without any defects.

• 한국IT서비스학회지
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• 제10권3호
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• pp.113-126
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• 2011

The smelting and the continuous casting of steel are important processes that determine the quality of steel products. Especially most of quality defects occur during solidification of the steel continuous casting process. Although quality control techniques such as six sigma, SQC, and TQM can be applied to the continuous casting process for improving quality of steel products, these techniques don't provide real-time analysis to identify the causes of defect occurrence. To solve problems, we have developed a detection model using decision tree which identified abnormal transactions to have a coarse grain structure. And we have compared the proposed model with models using neural network and logistic regression. Experiments on steel data showed that the performance of the proposed model was higher than those of neural network model and logistic regression model. Thus, we expect that the suggested model will be helpful to control the quality of steel products in real-time in the continuous casting process.

• 한국정밀공학회지
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• 제31권8호
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• pp.671-675
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• 2014

Nozzle ring is an important part of turbocharger which is applied to today's most diesel engines. Turbo charger nozzle ring is difficult to process and takes a high cost and a long time relatively. For this reason, it is largely produced by using a precision casting. Investment method, the representative technology of precision casting, has excellent dimensional accuracy and can produce complex shapes relatively easily. However, it is difficult to avoid the casting defects such as shrinkage cavity and short shot. This study is to predict the casting defects which could be occurred during the investment method by use of finite element analysis software and to design the process and mold of the marine turbocharger nozzle ring.