• Transactions of Materials Processing
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• v.20 no.2
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• pp.132-139
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• 2011

Three dimensional simulations were performed for the deformation of a slab in a roller hearth type slab reheating furnace. The main objective of this study was to examine the deformation pattern of the slab due to the shadow effect, i.e., the temperature difference between the upper and lower slab surfaces, in particular, the variations of displacement and effective stress in the vertical direction. A commercially available FE code, ANSYS Workbench $12.1^{TM}$, was used in a fully coupled thermo-elasticity analysis. Several cases with different slab surface temperatures were selected for the simulations. For the sake of simplicity, the temperature environment inside the furnace was assumed to be homogeneous for the upper and lower faces of the slab. Two cases of with different slab width were selected as model geometry. The deformation patterns were computed and explained in terms of periodicity and symmetry. The results indicated that the shadow effect leads to a significant displacement in the vertical direction and, thereby, is one of the main reasons for the separation of the slab and its supports. These simulations also predicted that the deformation is more severe along the transverse direction than along the longitudinal direction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.11
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• pp.51-57
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• 2014

This paper presents an algorithmic type computing technique of process coefficient in predicting model of temperature for reheating furnace and also suggests a design method of neural network model to find an adequate value of process coefficient for arbitrary operating conditions including test conditons. The proposed neural network use furnace temperature, line speed and slab information as input variables, and process coefficient is output variable. Reasonable process coefficients can be obtained by an algorithmic procedure proposed in this paper using process data gathered at test conditons. Also, neural network model output equal process coefficient under same input conditions. This means that adquate process coefficients can be found by only computing neural network model without additive test even if operating conditions vary.

• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.74-79
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• 2019

Specially designed test material was used for workpiece temperature measurement in the commercial reheating furnace and a linearized thermal model was applied for real time temperature prediction. The applied furnace is a walking beam type and specification of the workpiece is a STS302 which is 160mm in width, 160mm in height and 8100mm in length. Also six thermocouples were installed in width, height and length direction for temperature measurement. Ambient temperature in the furnace was raised to 1265 Celsius degrees and it took about 2.5 hours from loading to discharging of the workpiece. As a result of the experiment, temperature of the workpiece at discharge was 1257 Celsius degrees on the average in the range of 1256 to 1259 Celsius degrees, and predicted average temperature through the thermal model was 1251 Celsius degrees. Therefore, the deviation of the analysis and test results is about 6 degrees, which is within the range of 10 degrees required by the industry.

• ICROS
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• v.5 no.4
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• pp.8-13
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• 1999

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.11a
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• pp.9-12
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• 2004

• Journal of Korea Foundry Society
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• v.34 no.4
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• pp.123-129
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• 2014

This work presents the results of a thixo-extrusion process applied to aluminum alloy and and reheating characteristics of semi-solid A356 Alloy using have been discussed. The reheating experiment was performed using an electric resistance furnace and multi-stage heating for uniform reheating. The thixo-extrusion was performed at the optimal reheating conditions of the semi-solid A356 alloy, the the extrusion conditions were an extrusion ratio of 33 and ram speed of 6 mm/sec. The results showed that the thixo-extrusion of semi-solid A356 alloy fabricated by the cooling slope reduced the extrusion pressure by 180% in comparison with hot extrusion, and that a sound extrusion could be obtained in spite of the same extrusion ratio and strain rate.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.58-68
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• 2000

In this paper, a mathematical model of describing oxygen density in multi-band type reheating furnaces was presented. Model designed in this paper was composed of majorly two parts. One is a model regarding 'variation of existing gas'. The other is a model of showing 'variation of oxygen content'. Each model is designed by considering four factors related to variation of oxygen density based on chemical reaction, fluid dynamics and fuzzy theory. Four factors to be considered are combustion reaction in burner, fluid transfer between adjacent combustion bands, fluid transfer from furnace's inner space to external space, and input of external air via gates. According to simulation results, it was shown that varying pattern of oxygen density in each combustion band is similar to generally expected operation data in reheating furnace.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.175-180
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• 2003

An inverse problem to determine two-dimensional total heat exchange factor is studied for the prediction of the billet temperature in the reheating furnace. Temperature measurements by the experiment are used in the inverse analysis. This inverse analysis employs the conjugate gradient method. The total heat exchange factors for 12-zones of the cross-section of the billet are estimated. The estimated temperatures at measurement locations are in good agreements with the measured temperatures.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.970-981
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• 1991

본 연구에서는 총괄 열 흡수율법과 분할법이 지니고 있는 전열 해석상의 한계 를 보완하고 슬래브 가열로의 전열해석에 실질적으로 적용하기 위하여, 분할법으로 내 내 분위기 온도를 계산하고 이로부터 슬래브의 노내 온도이력을 예측하는 계산모델을 제시하였다. 계산모델의 유용성 확인을 위하여는, Fig.1에 보인 바와 같은 최대 슬 래브 처리량이 235ton/hr인 후판 가열로를 대상으로 하여, 노내 분위기 가스 온도 및 슬래브의 온도이력을 측정하고 이를 계산 결과와 비교하였다. 이와 아울러 연료유량, 슬래브 재로시간(residence time) 및 장입 온도등의 조업조건 변화가 분위기 가스온도 와 슬래브의 온도이력에 미치는 영향을 검토하여 가열로의 효율적 조업을 위한 자료를 제시하였다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.11a
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• pp.183-190
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• 2001