• 제목, 요약, 키워드: Wear

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하이브리드 금속복합재료의 윤활마모특성 (Lubricated Wear Properties of Hybrid Metal Matrix Composites)

  • Fu, Hui-hui;Bae, Sung-in;Ham, Kyung-chun;Song, Jung-il
    • 한국복합재료학회:학술대회논문집
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    • pp.135-138
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    • 2002
  • The purpose of this study is to investigate the lubricated wear properties of Saffil/Al, Saffil/$Al_2O_3/Al$ and Saffil/SiC/Al hybrid metal matrix composites fabricated by squeeze casting method. Wear tests were done on a pin-on-disk friction & wear tester with long sliding distance. The wear properties of the three composites were evaluated in many respects. The effects of Saffil, $Al_2O_3$ particles and SiC particles on the wear behavior of the composites under lubricated conditions were elucidated. Wear mechanisms were analyzed by observing the worn surfaces of the composites. The variation of coefficient of friction (COF) during the wear process was recorded by using a computer. Comparing with the dry sliding condition, all three composites showed excellent wear resistance when lubricated by liquid paraffin. Under intermediate load, Saffil/Al showed best wear resistance among them, and its COF value is the smallest. The dominant wear mechanism of the composites was microploughing, but microcracking also occurred for them to different extent.

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Rheo-compocasting법에 의한 SiC입자분산 복합재료의 마모특성에 관한 연구 (A Study on the Wear Characteristics of SiC Particle Dispersed Composites by Rheo-Compocasting Method)

  • 곽현만;최창옥
    • 한국주조공학회지
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    • v.13 no.3
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    • pp.238-247
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    • 1993
  • Microstructure, hardness and wear characteristics of $SiC_p/Al-6.5wt%Si-1.7wt%Mg$ alloy composites fabricated by the method of rheo-compocasting and hot pressing are investigated in this study. The dispersion of SiC particles in the composites is homogeneous and the hardness improves as additional amount increases. The wear amount of the matrix metal increases highly as wear rates increase, for the wear mechanism changes from adhesive wear to melt wear, and the matrix metal was coated on the surface of revolving disc and its weight increases. In the 5vol% composites, Fe is adhered on the surface of specimen by the projection of the dispersed hard SiC particles which have net-work structure and the coating layer is about $300{\mu}m$. But in the composite more than 20vol%, the wear amount of composite decreases because the SiC particles which have superior hardness, wear resistance and heat resistance properties resist wear, the abrasive wear turn out predominant wear mechanism and so the wear amount of revolving disc increases.

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항공기 브레이크 재료용 탄소/탄소 복합재료의 마찰 및 마모 거동 (Friction and Wear Behavior of Carbon/Carbon Composites for Aircraft Brake Material)

  • 우성택;윤재륜
    • Tribology and Lubricants
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    • v.9 no.1
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    • pp.62-69
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    • 1993
  • Friction and wear behavior of a carbon/carbon composite material for aircraft brake material was experimentally investigated. Friction and wear test setup was designed and built for the experiment. Friction and wear tests were conducted under various sliding conditions. Friction coefficients were measured and processed by a data acquisition system and amount of wear measured by a balance. Stainless steel disk was used as the counterface material. Temperature was also measured by inserting thermocouple 2.5 mm beneath the sliding surface of the carbon/carbon composite specimen. Wear surfaces were observed by SEM, and analyzed by EDAX. The experimental results showed that sliding speed and normal force did not have significant effects on friction coefficient and wear factor of the composite. Temperature increase just below the surface was not large enough to cause any thermal degradation or oxidation which occurred at higher temperature when tested by TGA. Wear film was generated both on the specimen and on the counterface at relatively low sliding speed but cracks, grooves, and wear debris were observed at high sliding speed. Friction coefficient remained almost constant when the sliding speed or normal load was varied. It is believed that the adhesive and abrasive components contributed mainly to the friction coefficient. Wear behavior at low sliding speed was governed by wear film formation and adhesive wear mechanism. At high speed, fiber orientation, ploughing by counterface asperities, and fiber breakage dominated wear of the carbon/carbon composite.

무윤활 미끄럼 마찰하에서 SiC 휘스커 및 입자강화 청동기지 복합재의 마모특성 (The Dry Sliding Wear Properties of $SiC_w$ and $SiC_p$ Reinforced Bronze Matrix Composites)

  • 이상로;허무영
    • Tribology and Lubricants
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    • v.9 no.2
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    • pp.49-55
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    • 1993
  • The dry sliding wear properties of the sintered Cu-10 wt%Sn bronze alloys reinforced with $SiC_w$ and $SiC_p$ were investigated by a pin-on-disc wear testing machine. The worn surfaces and the cross sections of the wear specimens and the wear debris were observed by SEM to study the effect of the variation of the ceramic phase contents in the composite and the wear condition on the wear behaviors. The wear of bronze matrix was dominated by the adhesive wear. The transition from mild to severe wear was found in the bronze matrix specimens at the applied load higher than 20N where the surface delamination caused the severe wear. The addition of $SiC_w$ and $SiC_p$ reinforcements in the romposites was proved to reduce the wear rate by the matrix strengthening at the applied load higher than 20N. SiC whiskers having a large length to diameter ratio which hold the deformed matrix were effective to hinder the crack propagation near the worn surface. Thus the maximum wear resistance was obtained in the composite reinforced by $SiC_w$ at the higher applied load.

전열관의 마모 체적형상에 따른 마모깊이 예측 (Prediction of Wear Depth of SG Tube based on Types of Wear Scar)

  • 유기완;김형진;박치용
    • 한국소음진동공학회:학술대회논문집
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    • pp.475-478
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    • 2005
  • Calculation of wear depth with regard to the wear topology is peformed numerically Four typical wear topology, that is round, crescent, flat, and diamond types are adopted to represent the configuration of wear volume. Diamond and flat types are the most severe topology for wear depth history, whereas round and crescent types have small increasing rate of wear depth to the wear volume. Based on this study we can guess that the most severe wear phenomena happens to be upper side of U-tubes in the KSNP SG, because flat or diamond wear will be generated by the wearing motion between tubes and diagonal, vertical, horizontal strips. The misalignment of tube at the stage of manufacturing or distortion of upper structure due to the thermal expansion or vibration of upper structure such as diagonal, vertical, and horizontal strips will be one of the main causes of flat or diamond wear.

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An hygienical study on fomentation wear textile and design

  • Shim, Boo-Ja
    • 패션비즈니스
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    • v.9 no.6
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    • pp.101-116
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    • 2005
  • The study with the subjects of the female consumers of the fomentation rooms in their 20s, this research made an investigation of the fomentation wear. Also, dye-fastness experiments of the wear's colors against washing and sweating were held. The following are the conclusions; 1. Survey Results of the Present Situations of Fomentation Wear Designs of the fomentation wear, 88% belonged to a T-shirt (upper clothes) and knee pants. The primary colors of the wear were in the order of gray (37.5%), white (31.3%), orange (25%), indigo (18.8%), and yellowish (18.8%). 43% of the wear companies used the same color for two-piece clothes, and 57% employed different colors for upper and lower clothes. 2. Consumers' Attitude about Fomentation Wear The key problem in the attitude to the wear, 25.9% pointed out the worries about physical exposure (like breasts and legs) owing to the improperness in designs and sizes. 32.8% of the subjects were also worried about physical silhouette exposure following sweating. The need for design improvement was felt as the subjects expressed their intention to use better fomentation wear in design and materials if the fare is higher. 3. Experimental Results of the Dye fastness of the Fomentation Wear Dye-fastness experiments by sweating appeared in the order of gray > white > pink. The results by washing were gray & white > pink. As laundry grew in number, the grade of dye fastness fell a little bit. In the fomentation environment with more laundry and more perspiration, dye fastness of the wear's colors against washing and sweating should be fully considered.

A Comparative Study on the Evaluation of the Wear Resistance in Zr-xNb-xSn Alloys

  • Lee, Young-Ho;Kim, Hyung-Kyu;Jung, Youn-Ho
    • KSTLE International Journal
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    • v.4 no.2
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    • pp.47-51
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    • 2003
  • Sliding wear tests have been carried out in room temperature air and water in order to compare the wear resistance of Zr-xNb-xSn alloys of various alloying elements (Nb and Sn). The main focus was to quantitatively compare the wear properties of the recently developed Zr-xNb-xSn alloys with the commercial ones using the evaluation parameters of the wear resistance with the consideration of the worn area. As a result, the recently developed alloys had a similar wear resistance compared with the commercial ones. The dominant factor governing the wear resistance was the protruded volume of the wear debris that was formed on the worn area in the air condition, but the accommodation of the plastic deformation on the contact area in water. In addition, the worn area size appeared to be very different depending on the tested alloys. To evaluate the wear resistance of each test specimen, the ratio of the wear volume or the protruded volume to the worn area ($D_e$ or $D_p$) is investigated and proposed as the evaluation parameters of the wear resistance.

Macroscopic Wear Behavior of C/C and C/C-SiC Composites Coated with Hafnium Carbide

  • Lee, Kee Sung;Sihn, Ihn Cheol;Lim, Byung-Joo;Lim, Kwang Hyun
    • 한국세라믹학회지
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    • v.52 no.6
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    • pp.429-434
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    • 2015
  • This study investigates the macroscopic wear behaviors of C/C and C/C-SiC composites coated with hafnium carbide (HfC). To improve the wear resistance of C/C composites, low-pressure chemical vapor deposition (LPCVD) was used to obtain HfC coating. The CVD coatings were deposited at various deposition temperatures of 1300, 1400, and $1500^{\circ}C$. The effect of the substrate material (the C/C substrate, the C/C-CVR substrate, or the C/C-SiC substrate deposited by LSI) was also studied to improve the wear resistance. The experiment used the ball-on-disk method, with a tungsten carbide (WC) ball utilized as an indenter to evaluate the wear behavior. The HfC coatings were found to effectively improve the wear resistance of C/C and C/C-SiC composites, compared with the case of a non-coated C/C composite. The former showed lower friction coefficients and almost no wear loss during the wear test because of the presence of hard coatings. The wear scar width was relatively narrower for the C/C and C/C-SiC composites with hafnium coatings. Wear behavior was found to critically depend on the deposition temperature and the material. Thus, the HfC-coated C/C-SiC composites fabricated at deposition temperatures of $1500^{\circ}C$ showed the best wear resistance, a lower friction coefficient, and almost no loss during the wear test.

초고강도강판 프레스성형용 금형의 CrN 코팅층 마모수명 예측 (Wear Life Prediction of CrN Coating Layer on the Press Tool for Stamping the Ultra High Strength Steel Sheet)

  • 이정흠;배상범;윤국태;허재영;김세호;박춘달
    • 소성가공
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    • v.26 no.3
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    • pp.137-143
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    • 2017
  • In this study, a wear test method was proposed to predict the wear life of the CrN layer coated on the surface of the press tools for manufacturing the auto-parts with ultra high strength steel (UHSS) with a tensile strength of 1.5 GPa. The pin-on-disc type wear test was carried out to confirm the feasibility and the reproducibility of the wear amount according to the test conditions such as the normal force, the sliding velocity, and the sliding speed. The test conditions were obtained from the finite element stamping analysis and the wear simulation. With the wear amount from the wear test, a prediction model of the wear depth in the CrN coating layer was proposed according to the test conditions with the design of experiments such as Taguchi method and the response surface method. The derived prediction model was then compared to the result of the Archard wear model, fully describing that the proposed model can effectively predict the wear life of the press tools for the auto-parts with UHSS.

The Development of Safety and Functional Snowboard Wear Design - Focus on the Safety Snowboard Pants for the Protection of Hip -

  • Kim, Mun Young
    • 한국의류산업학회지
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    • v.15 no.3
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    • pp.364-370
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    • 2013
  • This research helps secure the safety of snow boarders in an activity that is currently recognized as a minor specific hobby. The research goal is to develop a new board wear product with intensified safety and activity through the development of a safe and convenient snowboard wear that is wearable in ordinary life. The participants consisted of 31 snowboard club members evaluated from January 12 to January 19 at Eden-valley Ski Resort and Phoenix-park Resort in Korea. The result are as follows. First, what domestic snowboard wear consumers consider design difference and brand recognition a significant priority in choosing snowboard wear versus the functionality or safety of clothes. Second, concerning the evaluation of the developed product, they recognize the necessity of safety gear; however, they demand the convenient use of a safety gear with a fixation that can be attached and detached. A unity-type board wear was developed that enables an attachment and detachment that reflects the evaluation results. In conclusion, this research showed various market possibility of board wear into sports casual wear to be able to make it a fashion product through different design and demand of mixing it with general wear rather than functionality or activity, though board wear is a professional sports wear.