• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.143-144
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.703-704
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• 2008

• The Optical Journal
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• v.14 no.2 s.78
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• pp.36-43
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• 2002

• Laser Solutions
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• v.4 no.3
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• pp.1-10
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• 2001

• Journal of the Korean Society for Heat Treatment
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• v.20 no.4
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• pp.203-208
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• 2007

고출력 다이오드레이저(High Power Diode Laser, HPDL)는 독일을 중심으로 한 유럽내의 여러 국가에서 적용분야를 점차 높여가고 있으며, 금속소재에 있어서의 높은 흡수율 및 발진장치의 높은 에너지 변환효율이 중요한 요인이라고 할 수 있다. 레이저소스로부터 출력되는 사각형 또는 라인형의 레이저-빔은 다이오드레이저를 이용한 금속의 열처리분야에 매우 적합하며, 이미 Body-in-White 차체(Car Body) 양산라인의 브레이징 공정에는 수 년 전부터 실제 적용되어왔다. 또한, 다양한 빔 형상, 균일한 에너지 밀도, 낮은 운전비용, 간단한 유지보수, 좁은 설치공간, 손쉽게 이동이 가능한 구조, 광케이블을 이용한 레이저-빔의 전송 등 여러 장점으로 인하여 보다 유연하고 효과적인 생산환경을 구축할 수 있다는 것 또한 다이오드레이저의 응용분야를 확대하는 요인이 되었다.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.600-607
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• 2011

Recently, high carbon steel has become essential not only for shipbuilding parts, but also mass production. Its surface has been treated by carburizing, nitriding and induction hardening, but these existing treatments cause considerable deformation and increase the expense of postprocessing after treatment; furthermore, these treatments cannot be easily applied to parts that requiring the hardening of only a certain section. This is because the treatment cannot heat the material homogeneously, nor can it heat all of it. Laser surface treatment was developed to overcome these disadvantages, and when the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source. To estimate, microstructural changes and hardness characteristics of two parts (the surface treatment part, and parental material) are observed with the change of laser beam speed and surface temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.783-784
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.9-10
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• 2007

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.8
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• pp.961-969
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• 2007

The laser material processing has replaced a conventional material processing such as a welding, cutting, drilling and surface modification and so on. LTH(Laser Transformation Hardening) is one branch of the laser surface modification process. A lot of energy is needed for the LTH process to elevate workpiece surface to temperature of the austenite transformation($A_3$), which results from utilizing a beam with a larger size and lower power intensity comparatively. The absorptivity of the laser energy with respect to material depends on the wave length of a beam. This study is related to the surface hardening for the rod-shaped carbon steel by the high power diode laser(HPDL) whose beam absorptivity is better than conventional types of lasers such as $CO_2$ or Nd:YAG laser. Because a beam proceeds on the rotating specimen the pretreated hardened-phase can be tempered and softened by the overlapping between hardened tracks. Accordingly, the longitudinal hardness measurement and observation of the micro structure was carried out for an assessment of the hardening characteristics. In addition, a hardening characteristics as a hardenability of materials was compared in the point of view of the hardness distribution and hardening depth and width.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.5
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• pp.257-262
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• 2010

Recently, metal molding has become essential not only for automobile parts, but also mass production, and has greatly influenced production costs as well as the quality of products. Its surface has been treated by carburizing, nitriding and induction hardening, but these existing treatments cause considerable deformation and increase the expense of postprocessing after treatment; furthermore, these treatments cannot be easily applied to parts that requiring the hardening of only a certain section. This is because the treatment cannot heat the material homogeneously, nor can it heat all of it. Laser surface treatment was developed to overcome these disadvantages, and, when the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source.