• 열처리공학회지
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• 제11권3호
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• pp.159-167
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• 1998

In this study, friction-wear test was carried out on the carburized layer depth of a mechanical structure steel SNCM carburized with RX and LPG for 7hrs at $930^{\circ}C$ and also the wear properties of wear loss, wear rate, coefficient of friction, friction force and friction temperature were investigated. The wear properties for carburized layer of SNCM were tested on dry condition at the room temperature by the thrust load of 49~245N range at sliding speed of 0.2m/sec and the sliding speed of 0.2~1.0m/sec range at thrust load of 98N. Wear loss on the depth of carburizing layer was increased with increasing of thrust load and sliding speed, and with decreasing of hardness. The condition of worn surfaces were showed mild wear at less than the thrust load of 98N and sliding speed of 0.6m/sec but were showed severe wear at more than 98N and 0.6m/sec. The friction load and temperature were increased with increasing of thrust load but with increasing sliding speed was appeared minimum at 0.6m/sec. With increasing thrust load the wear rate was increased and the coefficient of friction was decreased, but with increasing sliding speed the wear rate and the coefficient of friction were decreased in 0.2~0.6m/sec and increased in 0.6~1.0m/sec, therefore 0.6m/sec in this testing is a transition velocity.

• Tribology and Lubricants
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• 제10권4호
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• pp.13-26
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• 1994

Effects of resin contents, number of carbonization, graphitization, sliding speed, and oxidation on friction and wear behavior of carbon/carbon composite materials were investigated. Friction and wear tests were carried out under various sliding conditions. An experimental setup was designed and built in the laboratory. Stainless steel disks were used as the counterface material. Friction coefficient, emperature, and wear factor were measured with a data acquisition system. Wear surfaces were observed by the scanning electron microscope. It has been shown that the average friction coefficient was increased with the sliding speed in the range of 1.43~6.10 m/s, but it as decreased in the range of 6.10~17.35 m/s. Specimens prepared by different numbers of carbonization. showed variations in friction coefficient and friction coefficient of the graphitized specimen was the highest. Friction coefficients depended on contribution of the plowing and adhesive components. As the number of carbonization was increased, wear factor was reduced. Wear factor of the graphitized specimens dropped further. In the case of graphitized specimens, sliding speed had a large influence on wear behavior. When the tribological experiments were conducted in nitrogen atmosphere, the wear factor was decreased to two thirds of the wear factor obtained in air. It is obvious that the difference was affected by oxidation. Results of friction and wear tests were applied to a neural network system based on the backpropagation algorithm. A neural network may be a valuable tool for prediction of tribological behavior of the carbon/carbon composite material if ample data are present.

• 소성∙가공
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• 제15권2호
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• pp.112-117
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• 2006

Sliding wear mechanism of a high nitrogen austenitic 18Cr-18Mn-2Mo-0.9N steel has been investigated. Dry sliding wear tests of the steel were carried out at various loads of IN-10N under a constant sliding speed condition of 0.15m/s against AISI 52100 bearing steel balls. Solution ($1050^{\circ}C$) and isothermal aging ($900^{\circ}C$) heat treatments were performed on the steel and the effect of the heat treatments on the wear was investigated. Wear rates of the solution-treated steel specimen remained low until 5N load, and then increased abruptly at loads above 5N. The rates of isothermally aged specimens were low and increased gradually with the applied load. Worn surfaces, their cross sections, and wear debris of the steel specimens were examined with a scanning electron microscopy. Phases of the heat-treated specimen and the wear debris were identified using XRD. The transformed phase underneath a sliding track was investigated and analyzed using a TEM. Effects of the phase transformation during the wear and $Cr_{2}N$ precipitates formed during the isothermal aging on the wear of the austenitic steel were discussed.

• 한국주조공학회지
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• 제24권6호
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• pp.323-330
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• 2004

This study aims to investigate on the effects of the microstructures on the wear characteristics of the different grey cast iron(GC) and spheroidal ductile cast iron(DCI). Wear test using wear tester of pin-on-disc type was carried out under the conditions of load 47.2N , velocity 0.2m/s, distance 4000m. At the GC, Wear rates depend on graphite type and oxide layer formed at wear surface. Weak rosette graphites are easily broken and formed wear debris over 30 ${\mu}m$. This wear debris occurs scuffing at wear surface. As a result of surface deformation, Narrow regions of the matrix between the graphite flakes and the contact surface lead to the failure of the necks. Wear rate for the DCI depended on hardness of matrix more than size of graphite.

• 한국생산제조학회지
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• 제21권1호
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• pp.33-39
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• 2012

The tool wear and failure in automatic production system directly influences the quality and productivity of a product, thus it is essential to monitor the tool state in real time. For such purpose, an ART2-based remote monitoring system has been developed to predict the appropriate tool change time in accordance with the tool wear, and this study aims to experimently find the relationship between the tool wear and the monitoring signals in cutting processes. Also, the roughness of workpiece according to the wool wear is examined. Here, the tool wear is indirectly monitored by signals from a vibration senor attached to a machining center. and the wear dimension is measured by a microscope at the start, midways and the end of a cutting process. A series of experiments are carried out with various feedrates and spindle speeds, and the results show that the sensor signal properly represents the degree of wear of a tool being used, and the roughnesses measured has direct relation with the tool wear dimension. Thus, it is concluded that the monitoring signals from the vibration sensor can be used as a useful measure for the tool wear monitoring.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.64-71
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• 2001

In this paper the ball-on-disk type sliding tests with boundary lubricated steels were carried out to verify the relation between surface profiles and wear as well as scuffing. Three kinds of surface roughness and asperity radius were produced on AISI 1045 steels using the different processes of grinding and polishing. Frictional forces and time to scuffing were measured. Also, the shape and amount of wear particles were analyzed to compare with original profiles. From the tests, it was confirmed that the size of wear particles are very related to original surface profile. The time to failures and wear amounts were sensitive to the surface spacing. The large surface spacing shows much longer sliding life and smaller wear amount than the others. Time to scuffing was increased with increasing surface profile spacing. The size of wear particles was increased and the amount was decreased with increasing surface profile spacing. Wear volume and wear rate K were decreased with increasing surface profile spacing. And after sliding tests, surface cracks of inner parts of the wear track occurred scuffing were observed and compared the differences about each specimen having the different surface profile spacing.

• 복식문화연구
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• 제27권3호
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• pp.251-263
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• 2019

As the spread of the health and wellness trend continues worldwide, many consumers are spending much time on sports activities and expressing their individuality through sportswear. This study analyzes the trade networks of major exporters and importers of athleisure wear to provide an exporting policy for Korean apparel companies. As a result, The USA was found to import the most athleisure wear. On the other hand, China had the largest number of athleisure wear exports, and India's exports, which are becoming increasingly important as apparel producers were notable. Next, using the concept of the centrality of social network analysis, it was found that the USA was the largest importer and the center of athleisure wear's export network, but its influence has decreased gradually since 2010. China has the highest out-degree and betweenness centrality and center in the export of athleisure wear. The centrality of Asian countries such as India and Vietnam has increased. In Korea, the import of athleisure wear has increased greatly, but the export of athleisure wear has continuously decreased. Korea has less price competitiveness than other developing countries in Asia, but many Korean athleisure wear clothing brands are now attracting popularity not only in Korea but also in other countries with their excellent technology and design. In the future, the exporting policy of Korea's athleisure wear should focus on high value-added and differentiated products.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1132-1133
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• 2006

Metal-bonded diamond impregnated tools are being increasingly used in the processing of stone and ceramics, road repair, petroleum exploration, etc. Although the main tool wear mechanisms have been identified, the scientific background is inadequate and fundamental research has to be carried out to better understand the tool field behaviour. This work addresses the complex issues of modelling abrasive wear of the metallic matrix under laboratory conditions. The generated data indicates that the matrix wear resistance can be assessed in a simple manner; whereas tests carried out on diamond impregnated specimens may aid prediction of the tool life in abrasive applications.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.272-278
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• 1999

It is the effective method to diagnosis damage process of gear system such as automobile transmission to observe wear particle in gear oil. We tested with new transmission and took out gear oil according to drive distance. 4 shape parameters of wear particles in gear oil were calculated and wear volume were presumed with the image processing system. To be applied to damage diagnosis of gear system in transmission of automobile, we discuss number of wear particles, shape characteristics and total wear volume according to driving distance.

• 한국생활과학회지
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• 제17권3호
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• pp.501-509
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• 2008

This research intends to help local small fashion industry to outgrow its limitation, preserving and developing environment-friendly dyeing tradition in Jeju renowned for persimmon juice dyeing. The study, then, aims to develop eco-friendly golf-wear designs, with maximizing advantages of natural dyeing (with persimmon juice, indigo plant, gallnut, cochineal, turmeric, and loess) such as rot-proofness, bacteria-proofness, stench-proofness and block of ultraviolet rays. The results are as follows: first, natural fabrics such as muslin(cotton 100%), linen(linen 100%) and spandex(mixed cotton 98%, polyurethane 2%) were developed into eco-friendly ones colored with various natural dye sources. Second, four kinds of golf-wear design were developed to stand out golf wear's natural image, focused on classic, neo-minimal style. The characteristic details and design elements of sportswear were added to basic golf wear design. Therefore, it is hopeful that those designs of naturally dyed golf wear for women could be utilized for other various purposes in the future.