• 한국분말재료학회지
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• 제29권3호
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• pp.240-246
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• 2022

Novel Ni- and Fe-based alloys are developed to impart improved mechanical properties and corrosion resistance. The designed alloys are manufactured as a powder and deposited on a steel substrate using a high-velocity oxygen-fuel process. The coating layer demonstrates good corrosion resistance, and the thus-formed passive film is beneficial because of the Cr contained in the alloy system. Furthermore, during low-temperature heat treatment, factors that deteriorate the properties and which may arise during high-temperature heat treatment, are avoided. For the heattreated coating layers, the hardness increases by up to 32% and the corrosion resistance improves. The influence of the heat treatment is investigated through various methods and is considered to enhance the mechanical properties and corrosion resistance of the coating layer.

• 한국산학기술학회논문지
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• 제8권4호
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• pp.938-945
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• 2007

본 연구는 국내의 금속열처리 중소기업을 대상으로 필요한 정보를 현장에서 수집하고 발취하는 체계적인 방법을 결정하는데 있다. 그러므로 본 연구는 부산지역에 소재한 중소기업을 중심으로 연구되었으며, 중요한 점은 열처리 공정 현장 데이터를 의미 있는 생산기술관리 정보 데이터로 변환하여 생산기술관리를 위한 금속열처리 프로그램을 개발하였다. 결론적으로 중소기업형 금속열처리의 생산정보시스템을 구축하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.125-126
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• 2006

The characteristics of the tool system give many effects into the costs and qualities for the finished components. Therefore, a tool life is one of the important issues on cold forging industry. However, since variables related with tool life are many complicated, the studies for solution should be investigated by the systematic research approach. In this study, heat-treatment of tool material is investigated to improve the tool life. Deep cryogenic treatment of tool steel is very efficient to improve the wear resistance due to the fine carbide. And, it is investigated that the shape and dimension of tool give effect into both tool life and quality of forged product.

• Journal of the Korean Wood Science and Technology
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• 제44권3호
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• pp.457-476
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• 2016

본 연구에서는 목재의 열처리가공에 대하여, 문헌 연구를 통하여 이와 관련된 주요 이슈 및 기술 동향을 조사하였다. 산업적으로 이용되는 주요 열처리기술은 네덜란드의 Plato-process, 프랑스의 Retification process, 독일의 OHT-process, 및 핀란드의 Thermowood process 등이었다. 열처리 공정상의 주요 영향인자들은 대상 수종, 가열 온도, 시간, 열전달 매질(air, 증기, 진공, 질소, 오일 등)이며, 이들 인자들을 변수로 한 최적조건 탐색 등의 연구가 주류를 이룬다. 열처리 목재는 치수안정성 증가, 중량 및 강도 감소, 부후균에 대한 내후성 향상에 변이, 변색균 및 해충에 대해 불충분한 저항성 등의 특징을 가진다. 열처리 목재의 내후성 향상을 위해 각 수종에 적합한 열처리 공정과 처리조건 탐색의 필요성이 시사되었다. 지속가능한 환경보존 및 목재자원 절약을 위해 열처리 목재의 새로운 용도 개발 및 이용 확대 노력이 반드시 필요한 과제인 것으로 고찰되었다.

• 동아시아식생활학회지
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• 제11권2호
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• pp.131-139
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• 2001

The physicochemical and sensory characteristics of brown rice flakes by different processing conditions such as flaking Process and their heat treatments were investigated to establish the brown rice flake processing procedure. To successfully make the compressed rice grain type flakes, the most appropriate water steeping conditions were 5 hours at 60'C. The brown rice flakes by compressed flaking procedure and heat treatment with microwave toasting showed the best crispiness-texture that tested from textrometer or sensory evaluation, and there was no significant difference between the source of rice varieties. The water absorption index(WAI) of tested flakes were negatively correlated with the water soluble index( WSI) and positively correlated with bowl life. The flakes made by compressed flaking procedure and heat treatment with microwave toasting showed longer bowl life, which is the length of the time that the cereal can retain its crispness after being soaked in milk.

• 소성∙가공
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• 제7권6호
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• pp.530-538
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• 1998

Elimination of the heat treatment process is very important in automation of metal forming since controlling heat treatment by computer has many difficulties and it has bottle neck problem. non-heat-treated steels materials which are not in need of heat treatment have been developed for cold forging. However to apply non-heat-treated steel to structural parts. it is necessary to prove reliability of mechanical properties. In order to define the reliability of mechanical properties we have investigated microstructure, hardness, the tensile strength compressive strength and tensile fatigue strength for both steels. Considering the results of high cycle fatigue test for both specimen the characteristics of non-heat-treated steel are decided on the yield strength, It has same tendency for heat-treated steel. Therefore non-heat-treated steel which has the appropriate yield strength may be applied in cold forging.

• 소성∙가공
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• 제8권6호
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• pp.626-633
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• 1999

$Al_{85}Ni_{10}Y_5$ (at. %) amorphous alloy ribbons have been produced by rapidly solidification process and consolidated by the conventional powder metallurgy method. The grains with ∼90 nm were obtained in the Al85Ni10Y5 alloy extrudates by hot-pressing followed by hot-extusion. To investigate the effect of heat treatment on microstructural change of the extrudates, heat treatment was carried out from 200℃ to 400℃ at the step of 50℃. In addition, mechanical properties of the extrudates were analysed from torsion test at the temperature range or 400∼500℃ under a strain rates of 0.2, 0.5, and 1.0/sec. The extrudates showed a flow stress of ∼190 MPa and low elongation of ∼150% at 400℃, contributing to the enhancement of ductility and hardness for extrudates. Also, grain boundary sliding was occurred in the $Al_{85}Ni_{10}Y_5$ alloy during hot deformation.

• 한국결정성장학회지
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• 제10권3호
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• pp.258-263
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• 2000

마이크로파 열처리공정이 여러 가지 CuO 조성을 가진 $Li_2O-2SiO_2$-xCuO 유리의 전기전도도와 결정화 거동에 미치는 영향을 조사하기 위하여 재래식 열처리 공정과 비교하였다. 각기 재래식과 마이크로파 가열법으로 열처리하였을 때, 시편들의 전기전도도는 CuO 함량이 증가할수록 증가하였고, 각 조성에서 마이크로파로 열처리된 시편이 재래식으로 열처리된 시편에 비하여 높은 전기전도도를 보였다. 또한 X-선 회절 실험 결과, 마이크로파 열처리는 $Li_2Si_2O_5$ , $Li_2Cu_5(Si_2O_7)_2$및 $Li_2Cu_O_3$상의 결정화 정도를 향상시켜주었다. $Li_2O-2SiO_2$-1.3CuO(30 mo1% CuO) 유리를 $500^{\circ}C$에서 30분 동안 재래식과 마이크로파로 열처리한 후 상온에서 측정한 시편들의 전기전도도는 각기 $0.11{\times}10^{-4}(\Omega \textrm {cm})^{-1}$과 $0.68{\times}10^{-4}(\Omega \textrm {cm})^{-1}$이었다. 마이크로파 에너지는 시편들의 결정화를 향상시키고, 전기전도도 값도 증가시킨다고 판단되었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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• pp.73-79
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• 2003

Recently many kinds of gears have been produced by forging in order to enhance the mechanical properties of the gears and the productivity of the process. Developments in forging technology are the reason for the increased usage. However, a critical problem of the forged gears is the dimensional change or distortion caused by elastic recovery after forging, and relief of the residual stresses during subsequent heat treatments. Distortion is of great concern to the manufacturers of precision parts, because it influences directly the dimensional accuracy and the grade of carburized bevel gears. In the present paper, distortion due to cold forging and heat treatment of bevel gears is investigated. Distortions of forged gears, machined gears and die are measured and compared. Numerical analysis is used to simulate the complete cold forging process and heat treatment process for the machined gears and shows good agreement with the experimental measurements.

• 소성∙가공
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• 제30권2호
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• pp.61-68
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• 2021

As part of efforts to reduce the weight of automotive body-in-white, a hybrid center pillar with high strength 7075 aluminum alloy (AA7075) sheet and carbon fiber reinforced plastic (CFRP) has been recently studied. In the fabrication of the AA7075-CFRP hybrid center pillar, the AA7075 sheet might go through heating-forming-in-die quenching (HFQ), artificial aging, hybridizing, and then paint baking processes. In this study, we investigate the effects of the heat treatment history associated with each process on the tensile strength of the AA7075 sheet. Typical heat treatment conditions are HFQ for 20 minutes at 480℃ and then cooling down with die, artificial aging of T6 temper for 24 hours at 120℃, hybridizing for 10 minutes at 150℃, and paint baking for 20 minutes at 180℃. The tensile strength of the AA7075 sheet is continuously increased by a series of heat treatments of hybridizing and paint baking and is expected to have yield stress above 500MPa without artificial aging of T6 temper.