• Title/Summary/Keyword: Roll Wear

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Fabrication and Evaluation of Wear Properties of CF/GNP Composites (Graphene Nanoplatelets을 첨가한 탄소직조복합재료의 제조 및 마모 특성 평가)

  • Kim, S.J.;Park, S.B.;Huh, C.H.;Song, J.I.
    • Composites Research
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    • v.28 no.3
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    • pp.124-129
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    • 2015
  • CNT and GNP have several excellent mechanical properties including, high strength, Young's modulus, thermal conductivity, corrosion resistance, electronic shielding and so on. In this study, CF/CNT, GNP/epoxy composites were manufactured by varying the CNT weight ratio at 2wt% and 3wt%, GNP weight ratio at 0.5wt% and 1 wt%. The composites were manufactured by mechanical method (3-roll-mill). Tensile, impact and wear tests were performed according to ASTM standards D638, D256 and D3181 respectively. The results showed that, CF/GNP0.5 wt%/epoxy composites gave good mechanical property in all composites, e.g., tensile strength, impact and were resistance.

Design of Digital Inclinometer for Measuring Postural Balance (자세 균형 측정을 위한 디지털 경사계 설계)

  • Myoung, Hyoun-Seok;Lee, Hyo-Ki;Kwon, Oh-Yun;Lee, Kyoung-Joung
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.1
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    • pp.50-56
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    • 2008
  • In this paper, a digital inclinometer to measure the angle and acceleration signals of subject laid on Roll was designed. The designed system consists of a tilt sensor, biaxial accelerometer, single chip microprocessor and Bluetooth module. The designed digital inclinometer was easy to handle and to wear. To evaluate the performance of the system, we measured simultaneously the angle and acceleration signals from the 3 subjects on the Roll using two instruments which are ZEBRIS and designed system. The measured signals were processed by statistical method and then the correlation coefficient of 0.93 was shown. From the results, the designed digital inclinometer is shown to be useful in assessment of body movement.

Grease from Korean Bentonites (국산 벤토나이트 그리이스 제조)

  • Tak Jin Moon;Oh Kwan Kwon
    • Journal of the Korean Chemical Society
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    • v.16 no.3
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    • pp.193-199
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    • 1972
  • Bentones from Korean bentonites were first prepared by reacting bentonites with high molecular weight imidazolines. The cation exchange capacity of bentonites was found more than 100meq/100g sample. Greases were then prepared by dispersing bentones into a lubricating oil and milling through a three-roll dispersion mill. Consistency in microscale, oxidation stability (static), water resistance, and wear property of the greases were tested by the ASTM methods, and good experimental results were obtained.

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Application of hot rolling oil lubrication on RM stands at Pohang Hot Rolling Mill No.2 (포항2열연 조압연스탠드(RM) 유압연시스템의 개발과 적용)

  • 김철희;조준길;유문석;한영환
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.10a
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    • pp.161-166
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    • 1997
  • Application of hot roiling oil lubrication technology was broadened to the field of RM stands of Hot Rolling Mill at Pohang works. The primary object was to improve the quality of the strip sttrface and the rolls by oil lubrication in hot rolling process. Prior to the actual field application preliminary test was conducted to evaluate the effect of hot rolling oil lubrication at RM stands. From the test, it has been found that the use of oil lubrication tends to prevent the progression of the heat cracks and thereby increases the quality of the strip surface and the wear life of the rolls. New hot rolling oil lubrication system was applied to the RM stands VSB, R1, R2, R3, R4 and edger rolls. With the introduction of a rolling lubricant, the quality of the strip surface and rolls was improved and overall roll dressing has decreased. Also there has been a improvement of productivity from the long roll life.

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Mechanical and wear properties evaluation of Al/Al2O3 composites fabricated by combined compo-casting and WARB process

  • Vini, Mohamad Heydari;Daneshmand, Saeed
    • Advances in Computational Design
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    • v.7 no.2
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    • pp.129-137
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    • 2022
  • Compo-casting method is one of the popular technique to produce metal based matrix composites. But, one of the main challenges in this process is un-uniform spreading of reinforced subdivisions (particles) inside the metallic matrix and the lack of desirable mechanical properties of the final produced composites due to the low bonding strength among the metal matrix and reinforcement particles. To remove these difficulties and to promote the mechanical properties of these kind of composites, the WARM ARB technique was utilized as supplementary technique to heighten the mechanical and microstructural evolution of the casted Al/Al2O3 composite strips. The microstructure evolution and mechanical properties of these composites have been considered versus different WARM ARB cycles by tensile test, average Vickers micro hardness test, wear test and scanning electron microscopy (SEM). The SEM results revealed that during the higher warm- ARB cycles, big alumina clusters are broken and make a uniform distribution of alumina particles. It was shown that cumulating the forming cycles improved the mechanical properties of composites. In general, combined compo-casting and ARB process would consent making Al/Al2O3 composites with high consistency, good microstructural and mechanical properties.

A Study on the Costume of the Gods in the Ancient Roman Myths (고대 로마 신화에 등장한 신들의 복식 연구)

  • 임상임;추미경
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.5
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    • pp.945-956
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    • 2001
  • The costume for gods in the Ancient Roman myth was studied by examining in the embossed-carving, sculptures, mural-painting and various documents of the period. The clothes item, hairstyle, symbol & ornaments and shoes of the gods in the Roman myths were analyzed to understand the formative process in the religious costumes, and results are as follows. First, the costumes for male gods are the same as those for ordinary men lived in ages, including toga, paludamentum, tebenna, tunica. The costumes for female gods are also the same as those for ordinary women lived in ages, including stola, palla, tunica. Second, the hairstyle of male gods is short curled-hair, twisty roll-up hair and braid long-hair due to the influence of Etrurian in the early days. Another hairstyle is appeared in form of the laurelled-crown. The hairstyle of female gods is curled long-hair, chignon style and braid roll-up hair decorated with hairband. Third, the symbol & ornaments which represent the responsible possession of male gods, are appeared in beard, a stick of the message, arrow-case, offering-dish, antlered-glass, shield, spear-handle, as the superhuman forms, such as the lightning shape. For female gods they are is appeared plastron, a stick of the message, flower. some female gods wear necklace, foot-ring, bracelet. Fourth, male gods wear shoes in forms of sandal, buskin, boots, but all female gods are in barefoot. It could be explained by the fact that a man-centered society in the ancient roman is reflected in the world of gods. As mentioned, Gods costume in Roman myths was very similar to or nothing different from the ordinary peoples in Rome. However, they used corps, sacrifices or sepcific symbols depending on the fields that they were responsible for in order to be distinguished from the ordinary people. This is the result from the peoples expression that they should keep a close relationship with Gods hoping to be protected, and rely on them under whatever circumstances.

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A Study in the High Temperature Wear and Thermal Shock Resistance of the Functional Gradient Thermal Barrier Coating by Air Plasma Spray with ZrO$_2$ (APS법에 의한 경사기능성 지르코니아 열장벽 피막의 열충격 및 고온내마모 특성에 관한 연구)

  • 한추철;박만호;송요승;변응선;노병호;이구현;권식철
    • Journal of the Korean institute of surface engineering
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    • v.30 no.4
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    • pp.272-280
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    • 1997
  • The Thermal Barrier Coation(TBC) to improve the that barrier and wear resistant propenrty in high temperature ofthe aircraftength between the accumlation of the aircraft engine and the automobile engine has usually the two layer structure. One is a creamic top layer for heat insulation and the other is a metal bond layer to facilitate the bond strength between the top ceramic layer and the substrate. But, the coated layers should be peeled off because of the accumulation of the thermal stress by the differance of the thermal expantion coefficient between metal and ceramics in a hrat cyclic environment. In this study, the intermediate layer by plasm spray process was introduced to reduce the thermal stress. The powders of plasm spray coating were the Yttria Stabilized Zirconia (YSZ), the Magnesia Stabillized Zirconia(MSZ) and NiCrAlY. the intermediate layer was sprayed with the powders of the bond cast for the purpose of test were executed. The high temperature wear resistance tends to decreasnceee wear and thermal shock test were exeucuted. The high temperature were resistance of the YSZ TBC is better that of the MSZ TBC. The wearrsistance tends to decrease accoring to incresing the temperature between $400^{\circ}C$to $600^{\circ}C$. The thermal shock life of the 3 layer TBC with YSZ top casting was the most outstanding thermal shock rsisstasnce. This means that the intermediate layer should play an importnat roll to alleviate the diffrerence of the thermal expansion coef frcients between metallic layer and cermics layer.

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The Effects of Nb, V on the High Temperature Wear and Corrosion of the Overlaying Materials for Continuous Casting Rolls (연주롤용 육성용접 재료의 고온마모 및 부식특성에 미치는 Nb, V의 영향)

  • Kim, C.G.;Whang, D.S.;Yoon, J.H.;Kang, C.Y.;Kwak, H.H.
    • Journal of Power System Engineering
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    • v.8 no.3
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    • pp.30-35
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    • 2004
  • In the steel making industries, the continuous casting process has been applied to the number of company because of its economical benefit. Casting rolls are utilized for frictional drive and transport of solidifying slap. Dimensional tolerances, mechanical stability and surface condition of the cast roll can affect both the surface and internal quality of the product being cast. To overcome these problems, the industry is accelerating on the rate of technology improvements. Samples were overlaid on the S45C steel by submerged arc welding process. And the hardness, wear, electrochemical corrosion and oxidation tests were carried out. Test results were that all these materials were satisfying basic requirements of caster rolls. By these results, the addition of 0.1%Nb and 0.15%V increase mechanical properties and tempering resistance by its superior carbide forming characteristics in low carbon $12{\sim}13%Cr$ martensitic stainless steels.

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A Study on the Fault Diagnosis of Roller-Shape Using Frequency-Domain Analysis of Tension Signals (장력신호의 주파수 해석을 이용한 롤 형상 이상 진단에 관한 연구)

  • Sin, Gi-Hyeon
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.12
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    • pp.107-114
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    • 2000
  • Rollers and rolls in the continuous process systems are noes of key components that determine the quality of web products. The condition of rollers and rolls(ex. eccentricity wear) should be consistently monitored in order to maintain the process conditions (ex. tension, edge position) within a required specification. In this paper, a new diagnosis technique is suggested to detect the defect of rollers/rolls (ex. eccentricity, wear) based on frequency domain analysis of web tension signal. The kernel of this technique is to use the spectrum amplitude of tension signal which allows to identify the fault rollers/rolls and to also diagnose the degree of fault in corresponding rollers and rolls. The experimental results proved that the suggested diagnosis technique can be successfully used to identify the defect rollers and rolls as well as to diagnose the degree of the defect of those rollers. The suggested technique can be applied to monitor and diagnose the shape of rollers and rolls in various multi-span web transport systems.

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Proposed Approaches on Durability Enhancement of Small Structure fabricated on Camera Lens Surface (카메라 렌즈 표면에 형성된 미세 패턴의 내구성 향상 기법 제안)

  • Park, Hong Ju;Choi, In Beom;Kim, Doo-In;Jeong, Myung Yung
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.5
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    • pp.467-473
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    • 2019
  • In this study, approached to improve durability of the multi-functional nano-pattern fabricated on the curved lens surface using nanoimprint lithography (NIL) was proposed, and the effects of the proposed methods on functionality after wear test were examined. To improve the mechanical property of ultraviolet(UV)-curable resin, UV-NIL was conducted at the elevated temperature around $60^{\circ}C$. In addition, micro/nano hierarchical structures was fabricated on the lens surface with a durable film mold. Analysis on the worn surfaces of nano-hole pattern and hierarchical structures and measurements on the static water contact angle and critical water volume for roll-off indicated that the UV curing process with elevated temperature is effective to maintain wettability by increasing hardness of resin. Also, it was found that the micro-scale pattern is effective to protect nano-pattern from damage during wear test.