• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.657-662
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• 1997

In these day, there have been shortage of construction workers and an increase of labor cost in our county. In order to overcome these problems, prefabricated and mechanized system of bar placing have been used in the construction fields. As a part of this tendency, welded wire fabric(WWF) reinforcement were studied several years ago. In this study, the required working hour. the labor power and the construction process of WWF reinforcement for the apartment building slabs are reported. From the result of field investigations, it is showed that the WWF reinforcement facilitates the field placing and the working time of WWF placing is saved, and then the labor cost of WWF reinforcement is less than that of the conventional bar reinforcement.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.282-288
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• 2001

This paper deals with determining the proper friction welding condition and analyzing various mechanical properties of friction welded joints of the bladepart heat resisting steel(STD11) for cold die punch to the shank part alloy steel(SCM440). And the in-process real-time weld quality evaluation technique by acoustic emission during friction welding of STD11 to SCM440 steels with higher confidence and reliability has been much required even though it might be the first trial approach for developing it. Also, the high temperature properties of STD11-SCM440 weld were considered in this paper.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.239-241
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• 2004

Stress intensity factor of semi-circular crack front was calculated by FEM, and also allowable crack size which doesn‘t break out the fracture by SCC in residual stress field of STS materials. Allowable crack size was increased with compressive residual stress provided by shot peening on material surface, and with magnitude of compressive residual stress for depth direction.

• Journal of Advanced Marine Engineering and Technology
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• 제12권1호
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• pp.47-54
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• 1988

TMCP steel manufactured by controlled rolling followed by accelerated cooling process is known to have extra-ordinary mechanical properties such as tensile strength and toughness. However, there is much uncertainty about the fatigue fracture characteristics of this steel. In this paper, the fatigue fracture behaviour of the TMCP steel in base metal and weldment were inspected through the Dynamic Implant test method. Those results were quantitavely compared with those of the ordinary normalized steel of same strength level. Moreover, the effect of the diffusible hydrogen included in the welded part on the fatigue fracture behaviour were made clear. As the experimental results, the fatigue fracture characteristics of the TMCP steel in case of base metal proved out to be superior to that of the normalized steel. However, the TMCP steel weldment including the diffusible hydrogen appeared to have inferior fatigue characteristics compared with the same conditioned normalized steel weldment.

• 한국기계가공학회지
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• 제5권4호
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• pp.86-92
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• 2006

In the automobile and machine industry, Forming type conveyer system have problems in that hinge belt plate are stretched, produce a noise and get abrasion. they make the machine get out of order. we make hinge belt thicker for reducing the trouble. Thick hinge belt was stronger. But it was heavier. And it was hard to come up with buyer's expectations because the mold which makes the hinge belt have limit of strength, life cycle and size. So, we developed the machine welded each part of hinge belt plate.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.493-497
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• 2002

In the part industry, pipe has required high accuracy in surface roughness and size. Especially, when producing the high frequency welding pipe, cutting process is very important as the finishing process that remove the hot welding bead. The objective of this paper is to investigate the hot machining high frequency welded pipe by simulation and experimental tests. To test the cutting process as hot machining, all cutting environment is reproduced in turning with heating system, and the test is accomplished by comparing with room temperature machining and hot machining in consideration of cutting force, tool wear and cutting temperature.

• 선박안전
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• 통권24호
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• pp.4-20
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• 2008

Stainless steel 304 or stainless steel 630 types using propeller shaft of a small ship or a FRP fishing boat generally restrain localization corrosion and abrasion damage occurrence to shaft bearing or grand packing contact. In general, the residual stress which remains after welding or heat treatment in material can cause the stress concentration or localization corrosion. In case of small ship, stainless steel such as STS304 has long been used for propeller shaft. Meanwhile, crew of small ship tend to reuse damaged propeller shaft after repair by welding and performing heat treatment to save cost. However, it was found that reused propeller shaft by repair often caused troubles in ship's operation. In this study, the basic guideline for maintenance and treatment of propeller shaft are investigated. From the results of investigation, remarkable deterioration of the material properties and corrosion resistance on the welded work part was observed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.36-41
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• 2003

Among welded structure bogies in use for high speed freight car, a part of bogies manufactured in 1999 and 2000 have found problems that failure occurs in its end beam. In case of a freight car a difference of weight between empty and loading conditions are worse than in case of a passenger car. Moreover its brake system is tread brake without second suspension system. A failure of end beam is supposed to be due to loading by brake rather than vertical loading by freight. This failure can make brake system useless and may be a cause of derailment in the worst case. In this study, we have proposed a simple torsion-free brake shoe holder hanger to remove torsion of hanger bracket which is supposed to be one of causes of failure and performed finite element analyses for making trial manufactures and its application.

• 보존과학연구
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• 통권20호
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• pp.81-90
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• 1999

We performed the non-destructive analysis of objects excavated at the Tomb of Mich’un-ri in Ch’ung-won. We analysed components using of Energy Dispersive X-Ray Micro-Fluorescence Analyzer. Glass bead inlaid with silver was classified as K2O-CaO-SiO2 type of glass. Purity of silver inlaid in the surface was verified above 97%.All small ear-ring were made by rolling up gold broad to a bronze wick. The composition ratio of Au : Ag has significantly higher 87 : 11 than bigear-ring. As a result of composition analysis of a welded part with big ear-ring, it contained the more Cu, Hg contents and the less Au, Ag contents than the surface of big ear-ring.

• 보존과학연구
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• 통권19호
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• pp.179-191
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• 1998

The Dumu of casted iron objects which is the big vessel for the prevention of fire to wood building is conserved in Kyongpok Palace(Dumu sizes：diameter 97cm, height 42cm, thickness 2cm, weight 250kg). The treated objects which some parts were lost, were not corroded, but cracted and broken by an external power, and strongly attached an cement layer on inside surface. First of all cement layer was mechanically removed by pneumatic needle scaler, welded to electric method for broken and cracked pieces, and then the lost sections were restored to use a epoxy resin and glass fiber. In order to prevent a damage during the handling, the restoration section of the inside surface was treated different colour in comparison with original part.