• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.181-184
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• 2008

오스테나이트 계열 스테인리스강의 경우 뛰어난 내열성으로 인해 가스 터빈 블레이드나 디스코 등으로 많이 사용되고 있다. 본 연구에서는 터빈 블레이드로 사용되는 316 스테인리스강의 고온 인장 및 저주기 피로 물성을 실험적으로 구하였다. 실험 결과 탄성계수와 항복강도, 최대인장강도 모두 온도 증가에 따라 감소하는 것으로 확인되었다. 소성변형률 진폭, 소성변형률 에너지 등의 인자들이 피로파괴에 미치는 영향도 조사하였다. 실험을 통해 얻어진 고온 인장 물성을 이용하여 316 스테인리스강으로 제작된 가스터빈 블레이드의 구조해석을 수행하였다.

• Journal of Biosystems Engineering
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• 제39권4호
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• pp.253-260
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• 2014

Purpose: This study investigated the harvesting properties of the giant miscanthus (Miscanthus ${\times}$ giganteus) to measure the required mowing power for different stem conditioning methods in order to shorten the drying time after mowing and the bale density so that the crop can be used as biomass in the winter season. Methods: The required mowing power and bale density were measured using a power measurement device, three different mower-conditioners, and a mid-sized round baler under different working speeds and conditioning methods. Results: For the various mower-conditioners, the average stem length from mowing was 0.86-0.91 m, and the available working speed was 1.6 m/s. The steel roller-type mower-conditioner showed better stem conditioning but could not mow over a working speed of 1.6 m/s. The required average power of the mower-conditioners varied from 23.8 kW for the steel roller-type rotary disk mower-conditioner with a working width of 2.4 m to 37.2 kW for the flail-type rotary disk mower-conditioner with a working width of 3.2 m at a working speed of 1.6 m/s. The bale densities were $155.8-172.2kg/m^3$. The highest bale density was measured for stems with no conditioning and a moisture content of 11.3% (d.b.) mowed by the rotary disk mower. The bale density was affected by the mowing method because of the low moisture content of the miscanthus stems. Conclusions: In terms of the working performance and conditioning statue, the steel roller-type mower-conditioner is a better choice at a working width of 2.4 m, while the flail finger-type mower-conditioner is better at a working width of 3.2 m. The type of mower-conditioner used for giant miscanthus harvesting should be determined by considering the harvest area, workable period, and working performance of a mower-conditioner and baler during the winter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.521-522
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.181-182
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• 2010

• Tribology and Lubricants
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• 제5권2호
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• pp.83-86
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• 1989

A wear transition mechanism during sliding in glass has been observed. Disk specimens of sodalime-silicate glass were slid against AISI 52100 steel with paraffin oil as lubricant. Observations of the micrrx structural change on the worn surface showed that semi-circular cone cracks (SCCCs) were suddenly produced after a certain critical sliding time. These SCCCs brought about the severe damage in the form of extensive microchipping during further sliding. It was shown that the abrupt appearance of the SCCCs is attributable to the grooves formed during sliding, which act as surface flaws.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.325-329
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• 2002

This study targets mainly to reduce the manufacturing costs of cam spindles and manufacturing of mechanical components with longer service durations through application of surface engineering techniques on cam spindles. Within the frame of this study, we have attempted to establish the performances of cam spindles manufacture from forged steel and SGCI, through performance of wear tests in plate-disk system, metalographic investigations, SEM imaging, EDS analyses and micro hardness scans on test samples having the same sizes with original cam that once obtained from casting of Spherical Graphite Cast Iron (SGCI) are subjected partially to Boronising and partially to hardening in a salt solution and cam spindles currently manufactured from CK 45 through cauterization based reshaping.

• 소성∙가공
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• 제24권4호
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• pp.272-279
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• 2015

The characteristics of the laser metal deposition parameters were studied to enhance the deposition efficiency using a diode pumped disk laser. STD61 hot tool steel plate and Fe based AISI M2 alloy were used as a substrate and powder for the laser metal deposition, respectively. Among the laser metal deposition parameters the laser power, track pitch and powder feed rate were used to estimate the deposition efficiency. From the experimental results, the deposition efficiency was shown to be excellent when 1.8kW laser power 500um track pitch and 10g/min of the powder feed rate were used. For this optimal condition the average hardness of the deposition track was approximately 830HV, and this value is 30~50% better than the hardness of the commercially produced tool steel after heat treatment.

• 전기학회논문지P
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• 제59권2호
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• pp.151-153
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• 2010

This paper is presented for the development of the brushless DC(BLDC) motor for the spindle motor of hard disk drives(HDD). A new BLDC Motor has the use of insulated, compacted, and iron powder for the armature core material of BLDC motors. Insulated iron powder in this paper is generally called soft magnet composite(SMC). The SMC is used for the stator of the motor instead of the laminated steel core. The motor used by SMC can have the good advantages in condition of the high frequency input power and small sized motor. It gets much more high efficiency than laminated steel core at same input power. The proposed motor has a technique of speed sensorless control. Experimental results show the performance of the proposed BLDC motors for an HDD.

• 한국생산제조학회지
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• 제9권3호
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• pp.41-47
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• 2000

The atmospheric humidity is varied between 30% and 90% with season in Korea. Thus the influence of humidity on the behavior of wear for tools and dies. This paper presents the influence of atmospheric humidity on the wear of carbon the un-lubricated pin-on-disk sliding contact. it was found that the severe wear is dominant at a low humidity and the mild wear is strongly related with the carbon concentration of the steel at a high humidity in this study. The experiments were carried out in a chamber where the humidity was accurately maintained by humidifier. To investigate the relationship three different carbon steels such as 1020, 1041, and 1034 steels were used.

• 동력기계공학회지
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• 제5권1호
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• pp.97-103
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• 2001

The present study was investigated changes of precipitation behaviour of laves phase in ferrite single phase and ferrite-martensite dual phase and the mechanical properties of 10%Cr ferritic alloys. In the ferrite phase, laves phase was mainly precipitated, whereas in the martensite phase, carbide was preferentially formed during the initial stage of aging and with increasing aging time. Laves phase and carbide were simultaneously precipitated by precipitation of laves phase at around carbide. Strength and toughness were lowered by the disk-type precipitator in the initial stage of aging and toughness was recovered with increasing of aging time and then, decreasing by precipitation of laves phase.