• Title, Summary, Keyword: Sliding wear

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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.

A Study on the surface hardening by repeated sliding contact (반복 미끄럼 접촉에 의한 표면층의 경화에 대한 연구)

  • 박준목;김석삼
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.80-88
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    • 1997
  • Repeated sliding contact wear test was performed with copper specimens to obtain the relationship between wear and surface hardening. Wear surface and wear track section were observed by optical microscopy. Wear volume and micro-vikers hardness of sublayer below wear surface were obtained. These results suggested that wear mechanism depended on contact load than sliding velocity. Therefore wear mechanism was abrasive wear within critical contact load and adhesive wear over critical contact load. Wear rate increased with contact load, sliding distance but decreased with sliding velocity. Surface hardening increased with sliding velocity and sliding distance but decreased with contact load.

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Effects of Corrosion Resistance Characteristics of Opponent Materials in relative Motion on Sliding Wear Behavior of Mild Carbon Steel (상대재 내식성이 철강재료의 미끄럼마모 특성에 미치는 영향)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.35 no.2
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    • pp.139-147
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    • 2019
  • This study investigates the effects of corrosion resistance characteristics of opponent materials in relative motion on the sliding wear behavior of mild carbon steel. Pin specimens made of mild carbon steel are tested at several sliding speeds against mating discs made of two types of alloyed steels, such as type D2 tool steel (STD11) and type 420 stainless steel (STS420J2), with different corrosion resistance characteristics in a pin-on-disc type sliding wear test machine. The results clearly show that the sliding wear behavior of mild carbon steel is influenced by the corrosion resistance characteristics of the mating disc materials at low sliding speeds. However, the sliding wear behavior at high sliding speeds is irrelevant to the characteristics because of the rising temperature. During the steady state wear period, the sliding wear rate of mild carbon steel against the type 420 stainless steel at a sliding speed of 0.5 m/s increases considerably unlike against the type D2 tool steel. This may be because the better corrosion resistance characteristics achieve a worse tribochemical reactivity. However, during the running-in wear period at low sliding speeds, the wear behavior of mild carbon steel is influenced by the microstructure after heat treatment of the mating disc materials rather than by their corrosion resistance characteristics.

Effect of Volume fraction of SiC Particle Reinforcement on the Wear Properties of 6061AI Composites (6061AI 복합재료 마모특성에 미치는 SiC입자 강화재 체적분율의 영향)

  • Kim, Heon-Joo
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.2
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    • pp.82-92
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    • 2002
  • In the present investigation wear behavior of the 6061AI composites reinforced with 5, 10, 20% SiC particles for dry sliding against a SM45C counterface was studied as a function of load and sliding velocity. Sliding wear tests were conducted at two loads(19.6 and 49N) and three sliding velocities(0.2, 1 and 2 m/sec) at constant sliding distance of 4000 m using pin-on-disk machine under room temperature. Presence of SiC reinforcement particles in the composites has displayed a transition from mild to severe wear at relatively higher applied load and sliding velocity compare to that of the matrix metal. As the volume fraction of SiC particles increased, the transition moved to a more severe wear conditions. Eventually, mild wear prevailed at a most severe wear conditions in this study, that was 49N load and 2 m/sec sliding velocity in 20% SiC particle/6061AI composite.

A Study on the Sliding Wear Characteristicsn of the Die Steel for the Cold Molding (냉간성형용 Die 강의 미끄럼 마멸특성에 관한 연구)

  • 전태옥;박흥식;류경곤
    • Tribology and Lubricants
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    • v.9 no.1
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    • pp.38-44
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    • 1993
  • The present study was undertaken to investigate the dry wear characteristics of die steel STD 11 for cold molding. The wear test was experimentally carried out under different conditions using a wear device, which was made in laboratory, and in which annular surfaces of wear testing specimens wear rubbed in dry sliding condition with varying the sliding speed, contact pressure, and sliding distance. The wear loss by variation of sliding speed was much in 0.3 m/sec and less in higher speed range above its sliding speed according to formation of the boundary lubrication film. The critical sliding speed with maximum value of the specific wear rate switched over to lower speed side according. as contact pressure increased. The critical sliding distance was increased with decrease in oxidation reaction velocity. The depth below subsurface showing maximum hardness (Hv) came out at the position, $60 \mu m$, of the maximum shear stress due to strain hardening.

A Study on the Rail Materials Technology for Subway Based on its Sliding Wear Behavior (지하철 레일의 미끄럼 마모거동을 고려한 재료설계에 대한 고찰)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.30 no.6
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    • pp.364-369
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    • 2014
  • To assess the wear behavior of rails against subway rail car wheels, we investigate the sliding wear behavior of pins derived from two types of rails (normal rails and heat-treated rails) against a disc derived from a subway rail car wheel, using a pin-on-disc-type tribometer. We base the sliding wear test conditions on the sliding conditions for wheel flange-rail gauge corner contact. We demonstrate the remarkable transition in the wear behavior of the pins derived from the rails, from severe wear to mild wear, as a function of the sliding distance. The wear rate of the heat-treated rail material in the running-in wear region is much lower than that of the normal rail material. Furthermore, the wear rates of the pins in the running-in wear region decrease with increasing hardness and with decreasing sliding speed. However, there is little difference between the heat-treated rail pin and the normal rail pin in the wear rate in the steady-state wear region. Stricter controls on the decarburized layer beneath the surface of rails are required to reduce the wear rate in the running-in wear region.

Sliding Wear Behavior of Pure Metal, Fe and Cu Having a Cubic Crystal System (입방정계 순 금속 Fe, Cu의 미끄럼 마멸 거동)

  • Yi, S.K.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.19 no.6
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    • pp.357-362
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    • 2010
  • Dry sliding wear behavior of pure Fe and Cu which have BCC and FCC crystal structure, respectively, was investigated. The wear characteristics of the pure metals with different crystal structure were compared. Dry sliding wear tests were carried out using a pin-on-disk wear tester at various loads under the constant sliding speed condition of 0.15 m/s against a silica ball at room temperature. Sliding distance was fixed as 600 m for all wear tests. Wear rate of a specimen was calculated by dividing the weight loss of the specimen after the test by the specific gravity and sliding distance. Worn surfaces and wear debris were analyzed by SEM. The wear of both pure Fe and Cu proceeded with surface deformation, resulting in similar wear rates despite of their structure difference under the current test conditions. Wear rates of both metals were low if the surface deformation due to wear forms thick surface-deformation layer that is strain hardened beneath the wearing surface. The pure Cu specimens showed a lot of oxides on the worn surface when tested at low loads less than 5 N, which resulted in very low wear rate.

Analysis of Sliding Wear Behavior of Mild Steel According to Hardness of Dissimilar Mating Materials (이종 상대재 경도에 따른 철강재료의 미끄럼 마모 특성 해석)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.32 no.6
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    • pp.195-200
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    • 2016
  • This study examines the wear behavior of mild steel pins mated against alloyed tool steel discs in a pin-on-disc type sliding test machine and provides specific clarification regarding the effects of disc hardness on the wear behavior of a mating mild steel pin. The analysis confirms these effects through the observation of differences in the wear rates of the mild steel pins at low sliding speed ranges. These differences occur even though the hardness of the mating disc does not affect the wear characteristic curve patterns for the sliding speeds, regardless of the wear regime. In the running-in wear regime, increasing the hardness of the mating disc results in a decrease in the wear rates of the mild steel pins at low sliding speed ranges. However, in the steady-state wear region, the wear rate of a pin mated against the 42DISC is greater than the wear rate of a pin mated against the 30DISC, which has a lower hardness value. This means that the tribochemical reactivity of the mating disc, which is based on hardness value, influences the wear behavior of mild steel at low sliding speed ranges. In particular, oxides with higher oxygen contents, such as $Fe_2O_3$ oxides, form predominantly on the worn surface of the 42DISC. On the contrary, the wear behavior of mild steel pins at high sliding speed ranges is nearly unaffected by the hardness of the mating disc.

Effect of Pro-eutectoid Ferrite and Cementite-spheroidization on the Sliding Wear Resistance of Carbon Steels (탄소강의 초석페라이트와 시멘타이트 구상화가 미끄럼마멸 거동에 미치는 영향 분석)

  • Hur, H.L.;Gwon, H.;Kim, M.G.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.23 no.6
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    • pp.345-350
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    • 2014
  • The current study elucidates the effects of cementite spheroidization and pro-eutectoid ferrite on the sliding wear resistance in medium carbon (0.45wt%C) and high carbon (1wt%C) steels. Both steels were initially heat treated to obtain a fully pearlite or ferrite + pearlite microstructure. Spheroidizing heat treatments were performed on both steels to spheroidize the pearlitic cementite. Sliding wear tests were conducted using a pin-on-disk wear tester with the steel specimens as the disk and an alumina ($Al_2O_3$) ball as the pin. The sliding wear tests were carried out at room temperature in air with humidity of $40{\pm}2%$. Adapted sliding distance and applied load was 300m and 100N, respectively. Sliding speed was 0.1m/s and the wear-track radius was 9 mm. Worn surfaces and cross-sections of the wear track were examined using an SEM. Micro Vickers hardness of the wear-track subsurface was measured as a function of depth from the worn surface. Hardness and sliding-wear resistance of both steel decreased with increased spheroidization of the cementite. The decrease was more significant in the fully pearlitic steel (1wt%C steel). The steel with the pro-eutectoid ferrite showed relatively higher wear resistance compared to the spheroidized pearlitic steel.

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.