• Title/Summary/Keyword: Wear

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Fracture Mechanics Study on Wear Mechanism of Ceramics -Discussions on Experimental Results of Wear Test- (세라믹의 마멸기구에 관한 파괴역학적 연구 -마멸실험 결과의 고찰-)

  • 김석삼;김재호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.3
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    • pp.636-645
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    • 1990
  • Analytically induced wear mechanism of elastic body under Hertzian contact is applied in acutual wear test of ceramics. There are two types of wear in ceramics, a large scale wear and a small scale wear. The large scale wear is commensurable with Hertzian contact area and the small scale wear with real contact area. Nondimensional parameter, S$_{c}$, is introduced and fully examined to estimate or predict wear rate of ceramics. Ceramic wear for S$_{c}$.leq.0.8 is in small scale wear and for S$_{c}$;geq.1.6 in large scale wear. wear.

Wear Behavior of Plasma Transferred Arc Deposited Layers for Ni - and Co - base Alloy (Ni계 및 Co계 합금 PTA 오버레이용접층의 마모거동에 관한 연구)

  • 윤병현;이창희;김형준
    • Journal of Welding and Joining
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    • v.19 no.5
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    • pp.540-547
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    • 2001
  • This study has evaluated the wear behavior of PTA (Plasma Transferred Arc) Inconel 625 and Stellite 6 overlays on Nimonic 80A substrate. Nimonic 80A alloy was also included for comparison. In order to evaluate the wear performance, three-body abrasive wear test and pin-on-disk dry sliding wear test were performed. Microstructural development during the solidification of deposits is also discussed. Wear test results show that the wear rate of Stellite 6 deposit is lower than that of Inconel 625 deposit and Nimonic 80A. The sliding wear resistance of overlay deposits follows a similar trend to the abrasive wear resistance, but for Nimonic 80A. The main wear mechanisms were abrasive wear for Inconel 625 deposit, adhesive wear and delamination for Stellite 6 deposit in pin-on-disk dry sliding wear test and ploughing in three-body abrasive wear test. Cross sectional examinations of the worn surface of pin specimens after pin-on-disk dry sliding wear test implies that the plastic deformation near worn surface has occurred during the wear testing.

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Quantitative Analysis of Wear Debris for Surface Modification Layer by Ferrography (Ferrography에 의한 표면개질층의 마모분 정량분석)

  • 오성모;이봉구
    • Tribology and Lubricants
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    • v.15 no.3
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    • pp.265-271
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    • 1999
  • Wherever there are rotating equipment and contact between surface, there is wear and the generation of wear particles. The particles contained in the lubricating oil carry detailed and important information about the condition monitoring of the machine. This information may be deduced from particle shape, composition, size distribution, and concentration. Therefore, This paper was undertaken to Ferrography system of wear debris generated from lubricated moving machine surface. The lubricating wear test was performed under different experimental conditions using the Falex wear test of Pin and V-Block type by Ti(C, N) coated. It was shown from the test results that wear particle concentration (WPC) and wear severity Index( $I_{S}$), size distribution in normal and abnormal wear have come out all the higher value by increases sliding friction time. Wear shape is observed on the Ferrogram it was discovered a thin leaf wear debris as well as ball and plate type wear particles. This kind of large wear shape have an important effect not only metals damage, but also seizure phenomenon.

DETERMINATION OF TRANSIENT WEAR DISTANCE IN THE ADHESIVE WEAR OF A6061 ALUMINIUM ALLOY REINFORCED WITH ALUMINA PARTICLES

  • Yang, L.J.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.217-218
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    • 2002
  • An integrated adhesive wear model was proposed to determine the transient wear and steady-state wear of aluminium alloy matrix composites. The transient wear volume was described by an exponential equation, while the steady-state wear was governed by a revised Archard equation, in which both the transient wear volume and transient sliding distance were excluded. A mathematical method was developed to determine both the transient distance and the net steady-state wear coefficient. Experimental wear tests were carried out on three types of commercial A6061 aluminum alloy matrix composites reinforced with 10%, 15% and 20% alumina particles. More accurate wear coefficient values were obtained with the proposed model. The average standard wear coefficient, as determined by the original Archard equation, was found to be about 51% higher.

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Sliding Wear Behavior of Carbon Steel in changing Sliding Speed (Effects of Mild Wear Mode Test on subsequent Severe Wear Behavior) (미끄럼 속도변화에 따른 철강재료의 미끄럼 마모거동 (중마모 거동에 미치는 연마모 도입시험의 영향))

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.36 no.3
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    • pp.117-123
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    • 2020
  • In this study, the effect of the pre-mild wear mode test condition on the subsequent severe wear behavior of carbon steel has been investigated when the wear mode is varied according to the sliding speed change during sliding contact. Two sliding speeds of 0.3 m/s and 3 m/s for the mild wear mode test have been chosen and a sliding speed of 1 m/s for the severe wear mode test. A mild wear mode test at two different sliding speeds has been carried out during the severe wear mode test and total sliding distance of the mild wear mode test has been changed at this time. As a result, it could be found that the wear rate of carbon steel under the severe wear mode test after performing a pre-mild wear mode test is significantly reduced, compared with that before performing. However, its wear rate was slightly higher than that under the mild wear mode test. Oxides produced during the pre-mild wear mode test have been found to play a significant role in reducing the wear rate under the subsequent severe wear mode test. In particular, it was found that the effect of a pre-mild wear mode test performed at the sliding speed of 3 m/s has more rapid and the reduction in the wear rate was greater than thst at the sliding speed of 0.3 m/s.

Evaluation of Microscopic Wear Characteristics for CVD TiN Coatings with SEM Tribosystem (SEM Tribosystem에 의한 CVD TiN막의 미시적 마모 특성 평가)

  • 문봉호
    • Journal of the Korean institute of surface engineering
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    • v.37 no.3
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    • pp.137-145
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    • 2004
  • This study surveys the microscopic wear of CVD TiN coatings in repeated sliding, using the SEM Tribosystem as in-situ system. According to the research, the depth of wear groove and the specific wear amount are changed by the transition of the microscopic wear mode. This investigation leads to the fact that the change of wear characteristics produces the transition of the wear mode. In this survey, four modes are observed for CVD TiN coatings with the thickness of 1.6$\mu\textrm{m}$: ploughing, powder formation, flake formation and coating delimitation. The microscopic wear properties is quantitatively evaluated in terms with the microscopic wear mode and the specific wear amount. These relationships prove that the observation of wear modes with a SEM Tribosystem is useful to evaluate wear properties.

A Study on The Wear Process and Wear Mechanism of the Alumina Ceramics with Different Alumina Purity (순도를 달리한 알루미나 세라믹스의 마멸과정 및 이의 기구에 관한 연구)

  • 전태옥;진동규
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.12
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    • pp.3404-3412
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    • 1994
  • The present study was undertaken to investigate the dry wear process and wear mechanism of the alumina ceramics in the purity variation which are used for the mechanical seal, roll, liner and dies. The wear test was carried out under different experimental condition using the wear testing device and in which the annular surface rubbed on dry sliding condition various sliding speed, contact pressure and sliding distance. In case of alumina purity 95%, there was speed range which wear loss increased rapidly owing to enlargement of heat impact force and temperature rise of wear surface. According as the alumina purity increased, wear loss decreased but alumina purity 85% with much void and defect had the most wear loss than any other alumina purity. The friction coefficient of sliding initial stage of wear curves has a large value but according to increase of sliding distance, it decreased owing to drop of the shear strength of wear surfaces.

Wear Behavior as Hardness Difference of Material in the Dry Sliding Wear Tests of Using Leaf-Spring (판스프링을 사용한 건식마모실험에서 재료경도에 따른 마모거동)

  • Kim, Jung-Hyun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.3
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    • pp.27-33
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    • 2008
  • It is shown that the rate of wear can be related to 'index of wear intensity' using a leaf-spring in the disc on disk on wear tests. Since both upper and lower specimens have used the same hardness values, equivalent hardness of 'the index of wear intensity' used the mean hardness value of specimens. This index is derived from the external variables of load, sliding speed and the hardness of the sliding pairs. The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a disc on disc configuration. The materials of the specimens are used as ten kinds along their hardness. Using experimental data, we figured the relationship between wear rate and index of wear intensity. A newly wear equation had been derived the result using a leaf-spring in disc on disc wear system.

Development of methodology for evaluating tribological properities of Ion-implanted steel (이온 주입한 강의 미시적 마모 튼성의 평가)

  • B.H. Moon;B.Y. Choi
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.9
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    • pp.146-154
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    • 1997
  • Ion implantation has been used successfully as a surface treatment technology to improve the wear. fatigue and corrosion resistances of materials. A modified surface layer by ion implantation is very thin(under 1 m), but it has different mechanical properties from the substrate. It has also different wear characteristics. Since wear is a dynamic phenomenon on interacting surfaces with relative motion, an effective method for investigtating the wear of a thin layer is the observation of wear process in microscopic detail using in-situ system. The change of wear properties produces the transition of wear mode. To know the microscopic wear mechanism of this thin layer, it is very important to clarify its microscopic wear mode. In this paper, using the SEM and AFM Rribosystems as in-situ system, the microscopic wear of Ti ion-implanted 1C-3Cr steel, a material for roller in the cold working process, was investigated in repeated sliding. The depth of wear groove and the speciffc wear amount were changed with transition of microscopic wear mode. The depth of wear groove with friction cycles in AFM tribosystem and specific wear amount of Ti ion-implanted 1C-3Cr steel were less about 2-3 times than those of non-implanted 1C-3Cr steel. The microscopic wear mechansim of Ti ion-implanted 1C-3Cr steel was also clarified. The microscopic wear property was quantitatively evaluated in terms of microscopic wear mode and specific wear amount.

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Effects of Alloying Elements on the High Pressure Wear Characteristics of Ductile Cast Iron I-Cu, Mn (구상흑연주철의 고압하 마멸특성에 미치는 합금원소의 영향 I-Cu, Mn)

  • Bang, Woong-Ho;Kang, Choon-Sik;Park, Jae-Hyun;Kweon, Young-Gak
    • Journal of Korea Foundry Society
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    • v.20 no.4
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    • pp.230-239
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    • 2000
  • High pressure wear characteristics of DCI(Ductile Cast Iron) were investigated through unlubricated pin-on-disc wear test. Wear test were carried out at speed of 23m/min, under pressure of 3MPa and 3.3 MPa. Cu and/or Mn were added to examine the effect of alloying elements on the high pressure wear characteristics of DCI. To investigate the relationship between wear characteristics and mechanical properties of DCI, Brinell hardness and V-notched Charpy impact energy were tested. Wear surface of each specimen was observed by SEM to determine the wear mechanism of DCI under high pressure wear condition. In the mild wear region, wear characteristics of alloyed DCI specimens were very similar to that of unalloyed DCI. But mild-severe wear transition was occurred at different wear distance and wear rate of DCI specimens were changed by alloying elements. In severe wear condition, wear rate of DCI was dramatically increased by the addition of Mn. Although the addition of Cu 0.46wt% did not decrease the wear rate of DCI in the severe wear region, but it delayed the mild-severe wear transition. Under high pressure wear condition, wear rate and mild-severe wear transition were not concerned with hardness of DCI specimens, but they were deeply associated with impact energy changed by alloying elements.

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