• Title/Summary/Keyword: wear debris

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Sliding Wear Mechanism of the High-Nitrogen Austenitic 18Cr-l8Mn-2Mo-0.9N Steel (고질소 Fe-l8Cr-l8Mn-2Mo-0.9N 강의 미끄럼 마멸 기구)

  • Kim, S.D.;Kim, S.J.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.15 no.2
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    • pp.112-117
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    • 2006
  • Sliding wear mechanism of a high nitrogen austenitic 18Cr-18Mn-2Mo-0.9N steel has been investigated. Dry sliding wear tests of the steel were carried out at various loads of IN-10N under a constant sliding speed condition of 0.15m/s against AISI 52100 bearing steel balls. Solution ($1050^{\circ}C$) and isothermal aging ($900^{\circ}C$) heat treatments were performed on the steel and the effect of the heat treatments on the wear was investigated. Wear rates of the solution-treated steel specimen remained low until 5N load, and then increased abruptly at loads above 5N. The rates of isothermally aged specimens were low and increased gradually with the applied load. Worn surfaces, their cross sections, and wear debris of the steel specimens were examined with a scanning electron microscopy. Phases of the heat-treated specimen and the wear debris were identified using XRD. The transformed phase underneath a sliding track was investigated and analyzed using a TEM. Effects of the phase transformation during the wear and $Cr_{2}N$ precipitates formed during the isothermal aging on the wear of the austenitic steel were discussed.

Sliding wear mechanism of the high-nitrogen austenitic 18Cr-18Mn02Mo-0.9N steel (고질소 Fe-18Cr-18Mn-2Mo-0.9N강의 미끄럼 마멸 기구)

  • Kim S. D.;Kim S. J.;Kim Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.105-108
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    • 2005
  • Sliding wear mechanism of a high nitrogen austenitic 18Cr-18Mn-2Mo-0.9N steel has been investigated. Dry sliding wear tests of the steel were carried out at various loads of 1N-10N under a constant sliding speed condition of 0.15m/s against AISI 52100 bearing steel balls. Solution $(1050^{\circ}C)$ and isothermal aging $(900^{\circ}C)$ heat treatments were performed on the steel and the effect of the heat treatments on the wear were investigated. Wear rates of the solution-treated steel specimen remained low until 5N, and then increased abruptly at loads above 5N. The rates of isothermally aged specimens were low and increased gradually with the applied load. Worn surfaces, their cross sections, and wear debris of the steel specimens were examined with a scanning electron microscopy. Phases of the heat-treated specimen and the wear debris were identified using XRD. Phases transformed underneath the sliding track during the wear were investigated and analyzed using TEM. Effects of the phase transformation during the wear and $Cr_2N$ precipitates formed during the isothermal aging on the wear of the austenitic steel were discussed.

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Observation on the Microstructures of Cu-TiB2 Composites with Wear Behavior (Cu-TiB2 복합재료의 마모거동에 따른 미세조직 관찰)

  • Lee, Tae-Woo;Kang, Kae-Myung
    • Korean Journal of Materials Research
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    • v.16 no.8
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    • pp.511-515
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    • 2006
  • The dispersion hardened $Cu-TiB_2$ composites are a promising candidate for applications as electrical contact materials. The $Cu-TiB_2$ composites for electrical contact materials can reduce material cost and resource consumption caused by wear, due to their good mechanical and electrical properties. In this study, we investigated the wear phenomenon for $Cu-TiB_2$ composites fabricated with hot extrusion, by varying particle sizes and volume fractions of $TiB_2$. The wear tests were performed under the dry sliding condition with a fixed total sliding distance of 40 m. The contact loads at a constant speed of 3.5 Hz were 20, 40, 60, and 80 N. The friction coefficients and wear losses were measured during wear tests. Worn surfaces and wear debris after wear tests were investigated using the scanning electron microscope and the optical microscope. The microstructures of interface between Cu matrix and $TiB_2$ particle before and after wear tests were studied by the transmission electron microscope.

Effects of the Microstructures on the Wear Characteristics of Cast irons (주철의 마모특성에 미치는 미세조직의 영향)

  • Kim, Sug-Won;Park, Jin-Sung;Lee, Hyung-Chul;Kim, Ki-Kon
    • Journal of Korea Foundry Society
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    • v.24 no.6
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    • pp.323-330
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    • 2004
  • This study aims to investigate on the effects of the microstructures on the wear characteristics of the different grey cast iron(GC) and spheroidal ductile cast iron(DCI). Wear test using wear tester of pin-on-disc type was carried out under the conditions of load 47.2N , velocity 0.2m/s, distance 4000m. At the GC, Wear rates depend on graphite type and oxide layer formed at wear surface. Weak rosette graphites are easily broken and formed wear debris over 30 ${\mu}m$. This wear debris occurs scuffing at wear surface. As a result of surface deformation, Narrow regions of the matrix between the graphite flakes and the contact surface lead to the failure of the necks. Wear rate for the DCI depended on hardness of matrix more than size of graphite.

The Characteristics of Wear Resistance of Cu-TiB2 Composites Reinforced by TiB2 Powders (TiB2 분말로 강화된 Cu-TiB2 복합재료의 내마모특성)

  • Lee Tae-Woo;Choi Jong-Un;Kang Kae-Myung
    • Korean Journal of Materials Research
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    • v.15 no.12
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    • pp.824-828
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    • 2005
  • In this study the effect of the content of $TiB_2$ on wear properties was investigated. $Cu-TiB_2$ composites have been fabricated by hot extrusion. Sliding wear tests were peformed by a pin-on-disk type wear test machine under dry condition and loads varied with from 20N to 80N at sliding speed 3.5Hz. The test results showed that the wear losses and the friction coefficients decreased with increasing $Cu-TiB_2$ volume fraction and increasing the size of $Cu-TiB_2$ particle. Wear property of $10{\mu}m,\;5 vol\%\; TiB_2$ specimen was excellent all of the wear specimens. It is thought that the increase of plastic flow resistivity due to uniform distribution of $10{\mu}m,\;5 vol\%\; TiB_2$ wear specimen would improve wear property. The worn surface and wear debris were examined by optical microscope and scanning electron microscope.

Frictional behaviour of Oxide Films Produced on S45C Steel by Plasma Nitrocarburizing and Post Plasma Oxidation Treatment (플라즈마 질탄화 & 후산화처리로 S45C강에 형성된 산화막의 마찰거동)

  • Jeong, Kwang-Ho;Lee, In-Sup
    • Korean Journal of Materials Research
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    • v.16 no.12
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    • pp.766-770
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    • 2006
  • The frictional behavior of oxide films on top of the plasma nitrocarburized compound layers was investigated in terms of post-oxidation treatment temperatures. The post-oxidation treatment at both temperatures($400^{\circ}C,\;500^{\circ}C$) produced magnetite($Fe_3O_4$) films which led to a significant enhancement in corrosion resistance. However, this process did not result in any improvement in frictional behavior of the nitrocarburized surface. The wear mechanisms were governed predominantly by the abrasive action of the slider on the surface irrespective of the counterface material(SiC and Bearing steel). When the specimen was sliding against a SiC counterface, the oxide films were destroyed during the early stage of the sliding process and the wear debris of the oxide film at the sliding track had a great influence on the friction coefficient. On the other hand, when sliding against a bearing steel counterface, the slider was mainly worn out due to the much higher hardness of the surface hardened layer. The fluctuation of the friction coefficient of $400^{\circ}C$-oxidized/ nitrocarburized specimen is much severer than that of $500^{\circ}C$ specimen, due to the less amount of wear debris.

Friction and Wear of Nitrogen Incorporated Diamond-like Carbon Films Under a Vacuum

  • Yoon, Eui-Sung;Kong, Hosung;Lee, Kwang-Ryeol;Oh, Jae-Eung
    • Tribology and Lubricants
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    • v.11 no.5
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    • pp.59-65
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    • 1995
  • Tribological behaviors of nitrogen incorporated amorphous diamond-like carbon films were experimentally measured under a vacuum ($3 \times 10^{-5}$ Torr) using a ball (AISI 52100 steel)-on-disk wear-rig. Nitrogen incorporated DLC films were deposited by r.f. plasma assisted chemical vapor deposition method. Mixtures of benzene and ammonia or nitrogen gases were used as the reaction gases for the r.f. PACVD, and Si (100) wafer was used as the substrate. In the tribo-test, effects of DLC film thickness and normal load in friction were measured and discussed. Results showed that friction of nitrogen incorporated DLC films from a mixture gas of benzene and ammonia was lower than that of 100% benzene, specially in the measurement of minimum coefficient of friction. Differences in frictional characteristics of nitrogen incorporated DLC films were explained with the changes in chemical structures of the films. Result also showed that friction of DLC films increased with the sliding contact cycle, which remarkably accompanied with roll-shaped wear debris. Mechanisms and roles of the polymer-like wear debris were presented and discussed.

A Study on the Prediction of Engine Condition of Supersonic Aircraft by the Condition Monitoring Technique. (Condition Monitoring을 이용한 초음속 항공기 엔진의 상태예측에 관한 연구)

  • 정병학;정동윤
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.176-182
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    • 1996
  • This paper describes an empherical equation which is to predict the engine condition of the supersonic aircraft. The equation, which is a function of running time of engine and engine oil, is derived from the trend analysis of JOAP data. Qualitative analysis is carried out to make up for the weak points in the current JOAP system. Also wear debris collected from the abnormal engine is analyzed by EDS to detect the damaged parts of engine.

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A Study on Synthesis and Wear Characteristics of Metal Dithiophosphates (Metal Dithiophosphates의 합성과 마찰 마모 특성에 관한 연구)

  • 김종호;강석춘;정근우;조원오;한두희;박미선
    • Tribology and Lubricants
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    • v.6 no.2
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    • pp.68-75
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    • 1990
  • The metal-dithiophosphates as lubricant additives for reducing friction and wear, increasing load-carrying capacity and a antioxidant are very important as new additives developed in these day. The synthetic results of Metal-DTPs were described. The wear test was conducted with 4-Ball machine and wear debris were analyzed by ferrography. The tribological performances of Metal-DTPs were compared with Zn-DTP.

A Study on the Wear Testing of Silding Members of Hydraulic Rotary Actuator (유압피스톤 모터용 습동부재의 마모실험에 관한 연구)

  • 김광영;함영복;이태서
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.608-613
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    • 1997
  • This study discusses the developmentof hydraulic rotary actuator design technology for industriol machinery and earthmoving equipment. The lubrication and wear analysis of sliding components of the machinery are very important parameters to sterngth the design technique. The analysis and were test are performed for the selected materials of the above mentioned coupled sliding members using the experimental results. One can selsct the better combination of sliding components.

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