• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1479-1485
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• 2010

In recent times, due to wire drawing of high carbon steel at a high speed to ensure a high productivity and high strength, axial residual stress are generated because of rapid increase in surface temperature. In the process, the temperatures of the wires increased because of the deformation of the wires and the friction between the die and wire. In particular, in the case of the wire drawing at a high speed, friction leads to a large temperature gradient so that considerable axial residual stress is generated on the surface. In this study, the relationship between axial residual stress and increase in the surface temperature was investigated, and a prediction model of uniform temperature was proposed. Then, a prediction model for residual stress was developed. The proposed model was verified by measuring the residual stress by X-ray diffraction on drawn wires.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.7
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• pp.743-749
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• 2014

In this study, a noncircular drawing (NCD) sequence for manufacturing high-strength and high-ductility pearlitic steel wires was investigated. Multipass NCD was conducted up to the 12th pass at room temperature with two processing routes (defined as the NCDA and NCDB), and compared with the wire drawing (WD). During the torsion test, delamination fracture in the drawn wire was observed in the 10th pass of the WD whereas it was not observed until the 12th pass of the NCDB. From X-ray diffraction, the circular texture component that increases the likelihood of delamination fracture of the drawn wire was rarely observed in the NCDB. Thus, the improved ability of the multipass NCDB to manufacture high-strength pearlitic steel wires with high torsional ductility compared to the WD (by reducing the likelihood of delamination fracture) was demonstrated.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1632-1636
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• 2007

Generally, fine high carbon steel wire is produced using a multi-pass drawing process with speeds over 1000 m/min. The productivity of the wire drawing mainly depends on achieving the highest drawing speed without breaking the wire. In the multi-pass drawing, as the final drawing speed increases, the temperature rises several hundred Celsius. High temperature of wire increases the brittleness and leads to breaks. The objective of this study is to design pass schedule and wire drawing machine for superhigh speed. In the drawing experiment, it was possible to increase the productivity through the increase in final speed from 1100 m/min to 2000 m/min.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.427-430
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• 2005

Improving the productivity of steel cord is required due to the increase in demand for it, even though steel cord being used as a reinforcement of a tire has been produced at multi-pass wet wire drawing process over 1000m/min. To improve the productivity, if just increase drawing speed, it causes temperature rise, fracture arisen by embrittlement during drawing process. To increase drawing speed affecting productivity, the variation of wire temperature during multi-pass wet wire drawing process is investigated in this study. In result, the multi-pass wet wire drawing process is redesigned. The redesigned wet drawing process with 27 passes efficiently controls wire temperature during drawing process. It, therefore, enables drawing process to be possible at ultra high speed with 2000m/min. It becomes possible to improve the productivity of steel cord in this paper because the increase in drawing speed could be achieved.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.8
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• pp.70-75
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• 2010

The aim of this study is to evaluate the axial residual stress in multi-pass drawn high carbon steel wire by using FE analysis and XRD. When FE analysis is applied to evaluate the residual stress in drawn wire of multi-pass drawing process, obtaining the reliable effective stress-strain curve at high strain is very important. In this study, a model, which can express the reliable effective stress-strain curve at high strain, is introduced based on the Bridgman correction and tensile test for multi-pass drawn high carbon steel wires. By using the introduced model, FE analysis was carried out to evaluate the axial residual stress in the drawn wires. Finally, the effectiveness of the FE analysis with the introduced stress-strain relation was verified by the measurement of residual stress in the drawn wires through XRD. As a result, the evaluated residual stress of FE analysis shows good agreement with the measured residual stress.

• Transactions of Materials Processing
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• v.26 no.3
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• pp.162-167
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• 2017

The tensile surface residual stress in the multi-pass drawn wire deteriorates the mechanical properties of the wire. Therefore, the evaluation of the residual stress is very important. Especially, the axial residual stress on the wire surface is the highest. Therefore, the objective of this study was to propose an axial surface residual stress prediction model of the multi-pass drawn steel wire. In order to achieve this objective, an elastoplastic finite element (FE) analysis was carried out to investigate the effect of semi-die angle and reduction ratio of the axial surface residual stress. By using the results of the FE analysis, a surface residual stress prediction model was proposed. In order to verify the effectiveness of the prediction model, the predicted residual stress was compared to that of a wire drawing experiment.

• Transactions of Materials Processing
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• v.28 no.5
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• pp.275-280
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• 2019

The aim of this study is to fabricate an ultra-fine pure rhodium wire using multi-pass wire drawing process. To manufacture $30{\mu}m$ ultra-fine rhodium wire from the initial $50{\mu}m$ wire, a multi-pass wire drawing process was designed based on the uniform reduction ratio theory. The elastic-plastic finite element analysis was then conducted to validate the efficacy of the designed process. The drawing load, drawing stress, and the distribution of the effective strain were evaluated using the finite element analysis. Finally, the wire drawing experiment was performed to validate the designed wire drawing process. From the results of the experiment, the diameter of the final drawn wire was found to be $29.85{\mu}m$.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.43-43
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• 2021

로즈마리(Rosmarinus officinalis)는 지중해 지역이 원산이고 꿀풀과에 속하는 다년생 식물로 자생지에서는 식물의 크기가 2m까지 자라는 관목성 식물이다. 식용, 약용, 미용, 향료뿐 아니라 관상용으로도 널리 이용되고 있고 특히 향이 좋아 세계 로즈마리 추출물 시장은 연평균 4.8%씩 증가하여 2027년에는 10억 달러를 넘을 것으로 예측된다. 우리나라도 소비 트렌드 변화에 따른 이용성 확대로 신선허브의 수요가 증가하고 있으나 아직은 허브 식물원료의 대부분을 수입에 의존하고 있고, 로즈마리 역시 식물원료뿐 아니라 가공품까지 외국에서 수입하여 사용하는 실정이다. 2018년 로즈마리 수입량은 신선상태 978kg, 건조상태 23,404kg으로 높은 수입의존에 따른 가격 상승과 긴 유통기간에 의한 품질 저하 등의 문제가 발생하고 있다. 본 연구는 로즈마리 어린 순 재배 적정 삽수 길이를 설정하고 어린 순 생산 가능 기간을 구명하여 추후에 고품질 로즈마리 어린 순 집약생산을 위한 다단재배기술을 확립하고자 수행되었다. 삽수 길이는 5, 10, 15cm로 하였고, 삽목 시기는 4월 하순 ~ 8월 하순까지 30일 간격으로 5회 실시하였다. 적정 삽수 길이 설정 실험에서는 15cm 삽수 발근률이 85.6%로 가장 높았으며 신초 출현시기는 5월 26일, 어린 순 생산시기는 6월 23일로 가장 빨랐고 수확시까지 소요일수는 56일로 가장 짧았다. 기대수량 또한 728g/m²로 가장 높았다. 로즈마리 어린 순 생산 가능 기간 구명 실험에서는 4월 28일 삽목시 발근율이 85.6%로 가장 높았고 육묘기간은 28일 어린 순 생산까지 소요일수는 56일로 가장 짧았다. 삽목 시기별 어린 순 품질 및 생산량은 4월 28일 삽목시 품질이 좋았으며 기대수량 또한 728g/m²로 가장 높았다. 결과적으로 상품성 있는 어린순 생산에 적합한 삽수 길이는 15cm, 삽목 시기는 4월 하순 경에 했을 때, 로즈마리의 생육상태, 수확까지의 기간, 어린 순 생산량 등 종합적인 면에서 가장 우수한 값을 얻을 수 있었다.

• Transactions of Materials Processing
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• v.14 no.8 s.80
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• pp.689-695
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• 2005

Multi-pass wet wire drawing process is used to produce fine wire in the industrial field. The production of fine wire through multi-pass wet wire drawing process with appropriate dies pass schedule would be impossible without understanding the relationship among many process parameters such as material properties, dies reduction, friction conditions, drawing speed etc However, in the industrial field, dies pass schedule of multi-pass wet wire drawing process has been executed by trial and error of experts. This study investigated the relationship among many process parameters quantitatively to obtain the important process information fur the appropriate pass schedule of multi-pass wet wire drawing process. Therefore, it is possible to predict the many important process parameters of multi-pass wet wire drawing process such as dies reduction, machine reduction, drawing force, backtension force, slip rate, slip velocity rate, power etc. The validity of the analyzed drawing force was verified by FE simulation and multi-pass wet wire drawing experiment. Also, pass redesign was performed based on the analyzed results, and the wire breakage between the original pass schedule and the redesigned pass schedule was compared through experiment.

• Transactions of Materials Processing
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• v.19 no.4
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• pp.224-229
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• 2010

During the multi-pass wire drawing process, wires suffer a great amount of plastic deformation that is through the cross-section. This generates tensile residual stress at surface of drawn wires. The generated residual stress on surface is one of the problems for quality of wires so that prediction and reduction of residual stresses is important to avoid unexpected fracture. Therefore, in this study, the effect of process variables such as semi-die angle, bearing length and reduction ratio on the residual stress was evaluated through Finite Element Analysis. Based on the results of the Analysis, a prediction model was established for predicting residual stress on the surface of high carbon steel(AISI1072, AISI1082). To identify the effectiveness of the proposed model, X-ray diffraction is used to measure the residual stresses on the surface. As the result of the comparison between calculated residual stresses and measured residual stresses, the model could be used to predict residual stresses in cold drawn wire.