• Title, Summary, Keyword: Wear

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Shape Study of Wear Debris in Oil-Lubricated System with Neural Network

  • Park, Heung-Sik;Seo, Young-Baek;Cho, Yon-Sang
    • KSTLE International Journal
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    • v.2 no.1
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    • pp.65-70
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    • 2001
  • The wear debris is fall off the moving surfaces in oil-lubricated systems and its morphology is directly related to the damage and failure to the interacting surfaces. The morphology of the wear particles are therefore directly indicative of wear processes occurring in tribological system. The computer image processing and artificial neural network was applied to shape study and identify wear debris generated from the lubricated moving system. In order to describe the characteristics of various wear particles, four representative parameter (50% volumetric diameter, aspect, roundness and reflectivity) from computer image analysis for groups of randomly sampled wear particles, are used as inputs to the network and learned the friction condition of five values (material 3, applied load 1, sliding distance 1). It is shown that identification results depend on the ranges of these shape parameters learned. The three kinds of the wear debris had a different pattern characteristics and recognized the friction condition and materials very well by neural network. We discuss how these approach can be applied to condition diagnosis of the oil-lubricated tribological system.

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Fretting Wear Mechanisms of Zircaloy-4 and Inconel 600 Contact in Air

  • Kim, Tae-Hyung;Kim, Seock-Sam
    • Journal of Mechanical Science and Technology
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    • v.15 no.9
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    • pp.1274-1280
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    • 2001
  • The fretting wear behavior of the contact between Zircaloy-4 tube and Inconel 600, which are used as the fuel rod cladding and grid, respectively, in PWR nuclear power plants was investigated in air. In the study, number of cycles, slip amplitude and normal load were selected as the main factors of fretting wear. The results indicated that wear increased with load, slip amplitude and number of cycles but was affected mainly by the slip amplitude. SEM micrographs revealed the characteristics of fretting wear features on the surface of the specimens such as stick, partial slip and gross slip which depended on the slip amplitude. It was found that fretting wear was caused by the crack generation along the stick-slip boundaries due to the accumulation of plastic flow at small slip amplitudes and by abrasive wear in the entire contact area at high slip amplitudes.

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Discussion on Wear Ope of Steel in Rolling Friction (철강재료의 구름마찰시에 발생하는 마모형태에 관한 연구)

  • 이한영
    • Tribology and Lubricants
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    • v.16 no.1
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    • pp.9-14
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    • 2000
  • It has been cleared in previous author's paper that the fatigue life before the pitting on the rolling contact surface with lubricant are influenced by the wear amount. In this study, the wear type has been clarified when wear amount is extremely large such as the case without lubricant. The test of rolling contact fatigue has been conducted under two different of herzian pressures and three different of slide ratios without lubricant. In addition, residual stress and half-value breadth using X-ray diffraction on worn surface have been measured as well as the wear amount. The results show that the pitting type wear by rolling contact fatigue has not been occurred when the wear amount is considerably large. Thus this type of wear has been deduced by the fatigue wear depending on delamination theory.

Fracture and Wear Behavior of Dental Composite Resins Containing Prepolymerized Particle Fillers (유기복합필러를 함유하는 차과용 컴퍼짓 레진의 파괴와 마멸거동)

  • Kim, Yeong-Bin;Kim, Gyo-Han;Kim, Seok-Sam;Im, Jeong-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.2
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    • pp.464-471
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    • 2000
  • The fracture and wear behavior of dental composite resins containing prepolymerized particle fillers were investigated. Composite resins such as Metafil, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to evaluate the effect of prepolymerized particle fillers in fracture and wear characteristics. Ball on flat wear tester was used for the wear test at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistances of Silux Plus and Palfique Estelite were better than those of Metafil and Heliomolar at the same experimental condition. It was found that the main wear mechanism was abrasive wear containing of plastic deformation of dental material.

A Study on Solid Particle Erosion Wear Characteristics of High Cr White Iron Hardfacing by Response Surface Method (반응표면분석에 의한 고 Cr 철계 오버레이 용접부의 분체침식마모 특성의 연구)

  • 이형근
    • Journal of Welding and Joining
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    • v.20 no.4
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    • pp.551-556
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    • 2002
  • Solid particle erosion wear characteristics of high Cr white iron hardfacing were investigated using the erosion wear test method according with the ASTM G76-95. Wear experiments, where the blast angle, blast distance and blast pressure were selected as test variables, were planned and analyzed by response surface method (RSM to evaluate the wear loss statistically and quantitatively. The measured wear losses well coincided with the calculated ones by the experimental equation. The wear loss of high Cr cast iron hardfacing was increased with blasting pressure, but affected in a complicated way by the blasting angle and distance. Erosion wear of high Cr cast iron hardfacing could be well predicted by RSM analysis of wear variables.

On the Abnormal Wear of Cylinder Liners and Piston Rings of the Marine Diesel Engine (박용(舶用) 디이젤기관(機關)의 실린더 라이너 및 피스턴 링의 이상마모(異常摩耗)에 관(關)하여)

  • Tae-Choon,Chung
    • Bulletin of the Society of Naval Architects of Korea
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    • v.8 no.1
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    • pp.95-102
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    • 1971
  • Since the fuel oil of the bunker C grade, which is commonly burnt in the large marine diesel engine, causes the corrosive wear of cylinder liners and piston rings, a cylinder oil of high alkality is frequently used to prevent the wear. This practice, however, brings us an another problem to cause the abnormal wear. In this study the author made an investigation of the mechanism of the abnormal wear by the experiments surveying the influences of the alkality of a cylinder oil and the temperature of cylinder wall on the wear. The major results obtained from this study are as follows; A cylinder oil of low alkality is clearly effective for the preventation of the abnormal wear. Therefore, it is recommended that, prio to using a cylinder oil of high alkality, a cylinder oil of low alkality should be used until bringing an end to the initial wear. It is also observed that the abnormal wear depends largely on the temperature of the cylinder wall, that is, the higher the temperature goes up the severer the wear grows.

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A Study on the Wear Characteristics and the Mechanism of KP-4M Steel for Plastic Molding (플라스틱성형용 KP-4M강의 마멸특성 및 이의 기구에 관한 연구)

  • 박흥식;전태옥;김동호
    • Tribology and Lubricants
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    • v.12 no.1
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    • pp.22-28
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    • 1996
  • This study was undertaken to investigate the dry wear characteristics and mechanism of KP-4M steel for plastic molding against SKD 61 hardened by heat treatment. The wear test was carried out under different conditions such as sliding speed, contact pressure, sliding distance, with frictional tester of pin on disc type. The wear loss on variation of sliding speed was little in lower speed range below 0.5 m/sec and in higher speed range above 1.5 m/sec,'but wear loss was high in intermediate speed range. The critical sliding speed, which showed the maximum value of specific wear rate, became lower with increased contact pressure. Increasing the contact pressure, the critical sliding distance Lcr which the wear mechanism changes from severe wear to mild wear was increased due to the decrease of oxidation reaction velocity. Through this study we suggested a model of generation and elimination process of wear debris of KP-4M steel for plastic molding.

A Study on the Corrosive Wear Mechanism on Atmospherical Temperature of STS 304 Steel (STS 304강의 분위기온도에 따른 부식마멸기구에 관한 연구)

  • 전태옥;박흥식;주창식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.2
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    • pp.399-406
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    • 1990
  • This paper is studied to know corrosive wear mechanism of STS304 steel on atmospherical temperature against mating material as the same. The corrosive test was carried out by rubbing the annular surface of two test pieces in distilled water and NaCl aqueous solution. The corrosive wear mechanism was investigated by S.E.M. The experimental results show that there is one Lcr transferring from severe wear to mild wear on change of NaCl concentration and atmospherical temperature, and which is the other still remaining in server wear state. It was found that the critical sliding distance Lcr shorten with increasing NaCl concentration but it is longer with ascending atmospherical temperature and the mild wear state still continues under the condition of high generation rate and elimination rate of the corrosive product. Considering upon the result, the model of corrosive wear mechanism is proposed.

An Experimental Study on the Effect of Contaminated Lubricants on Wear Characteristics (오염된 윤활유가 마멸특성에 미치는 영향에 관한 실험적 연구)

  • Kim, Hae-Won;Hong, Jae-Hak
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.2
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    • pp.113-123
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    • 1990
  • To study deleterious effects of contaminants contained in lubricating systems, the effects of fine alumina particle concentration and size on the critical failure load, friction and wear characteristic were examined on boundary lubrication condition using the four ball machine. The following conclusions are deduced: The abrasive is found to cause a transition from mild wear to severe wear at less severe conditions than with clean oil. In mild wear region the friction and wear increase with particle size and concentration, but in severe wear region do not exhibit any definite trend. In relation to film thinckness there is a threshold of particle size beyond which the failure load no longer decreases with particle size.

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Effect of Primary Si size and Residual Stress on the Wear Properties of B.390 Al Alloys (B.390 알루미늄 합금의 마모특성에 미치는 초정Si 입자크기와 잔류응력의 영향)

  • Kim, Heon-Joo;Kim, Sung-Jae
    • Journal of the Korean Society for Heat Treatment
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    • v.19 no.1
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    • pp.20-29
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    • 2006
  • Wear behaviour of B.390 aluminum alloy with different particle sizes of primary Si against a SM45C counterface was studied as a function of wear load and sliding velocity, using pin-on-disk apparatus under dry condition. The wear rate of specimen with fine primary Si particles showed increased wear resistance at high wear load, on the other side wear resistance of coarse primary Si particle size was improved at low wear load. As the compressive residual stress in the matrix increased remarkably by liquid nitrogen(LN) treatment, wear resistance of the LN treated specimen was more excellent than that of T6 treated specimen.