• Title/Summary/Keyword: Wear mechanisms

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Wear and Operation Characteristics of Acetal and Nylon Pinion Against Steel Gear (아세탈과 나일론피니언의 마멸 및 운전특성에 관한 고찰)

  • Kim, Chung-Hyeon;Lee, Seong-Cheol;An, Hyo-Seok;Jeong, Tae-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.9 s.180
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    • pp.2387-2396
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    • 2000
  • Wear and operation characteristics of Nylon and Acetal pinion against steel gear were studied to gain a better understanding of their tribological and mechanical behavior. Tests were conducted with power circulating gear test rig under unlubricated conditions. Specific wear rates were measured as a function of applied load and total revolution. The worn tooth surfaces were examined with a profile projector and camera. Nylon pinion showed lower specific wear rates than Acetal pinion, but it revealed breakage at high load. Principal wear depths were developed at tooth tip and below the pitch line of pinion. Life estimation for the Nylon pinion was made by taking into account steel gear equivalent Hertz stress and average sliding velocity. The dominant wear mechanisms were adhesion and abrasion.

Abrasive Wear Characteristics of Materials for Diesel Engine Cylinder Liner and Piston Ring (디젤엔진 실린더 라이너-피스톤 링 소재의 연삭 마멸 특성)

  • Jang, Jeong-Hwan;Kim, Jung-Hoon;Kim, Chang-Hee;Moon, Young-Hoon
    • Journal of the Korean Society for Heat Treatment
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    • v.20 no.2
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    • pp.72-77
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    • 2007
  • Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

Effects of Cryogenic Temperature on Wear Behavior of 22MnB5 Under Cold Stamping (극저온이 22MnB5강의 냉간 스탬핑 마모에 미치는 영향)

  • Ji, Min-Ki;Noh, Yeonju;Kang, Hyun-Hak;Jun, Tea-Sung
    • Tribology and Lubricants
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    • v.38 no.6
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    • pp.241-246
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    • 2022
  • This paper presents the effects of cryogenic temperature on the wear behavior of 22MnB5 blank under cold stamping. After immersing the blank in liquid nitrogen (LN2) for 10 min, a strip drawing test was performed within 10 s. The hardness was measured using the Rockwell hardness test, which increased from 165 HV at 20℃ to 192 HV at cryogenic temperature. The strip drawing test with 22MnB5 blank and SKD61 tool steel shows that for the different wear mechanisms on the tool surface with respect to temperature; adhesive wear is dominant at 20℃, but abrasive wear is the main mechanism at cryogenic temperature. As the friction test is repeated, sticking gradually increases on the tool surface at 20℃, whereas the scratch increases at cryogenic temperature. For the friction behavior, the friction coefficient rapidly increases when adhesive wear occurs, and it occurs more frequently at 20℃. The results for nanoindentation near the worn blank surface indicate a difference of 1.3 GPa at 20℃ and 0.8 GPa at cryogenic temperature compared to the existing hardness, indicating increased deformation by friction at 20℃. This occurs because thermally activated energy available to move the dislocation decreases with decreasing temperature.

Analysis of Wear Resistance and Wear Mechanism Change of Ti-5Mo-xFe (x=2,4 wt%) Alloys Based on Fe Addition (Ti-5Mo-xFe (x=2,4 wt%) 합금의 Fe 첨가에 따른 마모 메커니즘 변화와 내마모 특성 분석)

  • Yeong-Hun Jung;Yong-Jae Lee;Dong-Geun Lee
    • Journal of the Korean Society for Heat Treatment
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    • v.37 no.5
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    • pp.247-254
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    • 2024
  • Metastable β titanium alloys have been used in implants due to their high specific strength and excellent corrosion resistance. However, the high cost of β-stabilizing elements limits the application of metastable β titanium alloys. Consequently, research has been conducted on low-cost metastable β titanium alloys using relatively inexpenisve β-stabilizing elements such as Mo and Fe. This study analyzes the wear resistance of Ti-5Mo-xFe (x=2,4 wt%) alloys, designed and manufactured as low-cost metastable β titanium alloys. The wear mechanisms of Ti-5Mo-xFe alloys were identified through ball-on disk testing and observation of the worn surfaces. Additionally, the influence of Fe addition on the microstructure and the resulting changes in wear resistance were examined. The wear resistance of the Ti-5Mo-xFe alloys were evaluated in comparison to the Ti-6Al-4V ELI alloy.

A Study on Fretting-Wear Behavior of Inconel 690 due to Surrounding Temperature (주위 온도에 따른 Inconel690의 마멸 거동에 관한 연구)

  • 임민규;박동신;김대정;이영제
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.11a
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    • pp.296-303
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    • 2001
  • In nuclear power steam generators, high flow rates can induce vibration of the tubes resulting in fretting wear damage due to contacts between the tubes and their supports. In this paper the fretting wear tests and the sliding wear tests were performed using the steam generator tube materials of Inconel 690 against STS 304. Sliding tests with the pin-on-disk type tribometer were done under various applied loads and sliding speeds at air and water environment. Fretting tests were done under various vibrating amplitudes, applied normal loads and various temperatures. From the results of sliding and fretting wear tests, the wear of Inconel 690 can be predictable using the work rate model. Depending on normal loads and vibrating amplitudes, distinctively different wear mechanisms and often drastically different wear rates can occur. At room temperature, the wear coefficient K of Inconel 690 is 7.57${\times}$10$\^$13/Pa$\^$1/ in air and it is 1.93${\times}$10$\^$13/Pa$\^$1/ in water. At room temperature, it is found that the wear volume in air is more than in water. In water, the wear coefficient K at 50$^{\circ}C$ and 80$^{\circ}C$ is 4.35${\times}$10$\^$-13/Pa$^1$ and 5.81${\times}$10$\^$-13/Pa$^1$ respectively, Therefore, it is found that the wear volume extremely increases by increasing on temperature in water. This study shows that the dissolved oxygen with temperature increment increases and the wear due to fluidity is severe.

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A Study on Wear Mechanism in Diamond-like Carbon Coated Surface by Finite Element Analysis (유한요소해석에 의한 DLC 코팅면의 마멸기구에 대한 연구)

  • Lee, Jun-Hyuk;Park, Tae-Jo
    • Tribology and Lubricants
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    • v.29 no.6
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    • pp.366-371
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    • 2013
  • Various heat treatment and surface coating methods have been applied to machine parts. Nowadays, diamond-like carbon (DLC) coatings are widely used because of their excellent tribological characteristics. Despite the numerous studies on DLC-coated engineering surfaces, the exact wear mechanisms related to the coating thickness and elastic modulus have not been fully examined. In this study, a sliding contact problem between a small spherical hard particle and a DLC-coated steel surface is analyzed using a nonlinear finite element code, MARC. The maximum principal stress distributions and deformed surfaces are compared for different coating thicknesses and Young's modulus values. Plastically deformed surface shapes such as a groove and torus indicate that the most dominant wear mechanism for a DLC-coated surface is abrasive wear. Fatigue wear can also play a role in a case where the coating thickness is relatively large and the elastic modulus is high.

Wear Behavior of TiN Coatings Deposited on High Speed Steel and Alloy Tool Steel (TiN 코팅된 고속도강과 합금공구강의 마멸거동)

  • 김석삼;서창민;박준목
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.3
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    • pp.705-712
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    • 1995
  • The wear characteristics and wear mechanisms in TiN coating deposited on high speed steel and alloy tool steel by ion plating were investigated. Pin on V-block wear tester was used for a wear test method. The specimen was composed of three kinds of high speed steel and alloy tool steel which had different hardness by changing the heat treating condition. Three kinds of coating thickness were also applied to each specimen. Microscopic observation of worn surfaces was made by SEM. The scratch test of coating surface by the ion plating showed that critical load to break the coating interface was greater than 50N. The critical load increased with both substrate hardness and coating thickness. The wear resistance of TiN coated high speed steel became 10 times greater than that of non-coated ones. SEM observation showed that leading edge of contact was compressive and trailing edge was under maximum tensile stress and then surface cracking broke out perpendicular to sliding direction.

Study in the Mechanisms of Formation of Transfer Film under the Condition of Wear of Steel AISI1020 by Natural Rubber

  • Wang, De-Guo;Zhang, Si-Wei;He, Ren-Yang;Li, Ming-Yuan
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.223-224
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    • 2002
  • The mechanisms of formation of transfer film under the condition of wear of Steel AISI1020 by natural rubber were investigated. The transfer film was observed and the formation mechanisms were clarified. The formation process of transfer film on the worn surface of the steel could be divided into two stages. Firstly, the adhesive layer emerged on the worn surface of the steel by adhesion of natural rubber. in which the macromolecular chains of natural rubber joined to the surface of the steel by Van der Waals' force. And then, the iron atom and metal oxide reacted with the macromolecular of natural rubber in the adhesive layer and produced Fe-polymer compound. As a result, the transfer film was formed on the worn surface of the steel. The transfer film was joined to the worn surface of the steel by the chemical bonds and electrostatic force.

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Friction and Wear Characteristics of Plasma Coated Surface of Casting Aluminum Alloy (플라즈마 코팅한 주조용 알루미늄합금의 마찰 및 마멸특성)

  • Chae, Young-Hun;Ren, Jing-Ri;Park, Jun-Mock;Kim, Seock-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.5
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    • pp.791-799
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    • 1997
  • The wear characteristics and wear mechanisms of plasma sprayed Al/sub 2/ O/sub 3/-40%TiO/sub 2/ and Cr/sub 2/O/sub 3/ deposited on casting aluminum alloy(AC4C) were investigated. Specimens were processed for various coating thicknesses. Ball on disk type wear tester was used for wear test. The scratch test on plasma sprayed coating surface showed that critical load to break the coating layer was greater than 40 N. The critical load increase with the increase of coating thickness of specimens. The friction coefficient of Cr/sub 2/O/sub 3/ coating layer was less than that of Al/sub 2/O/sub 3/-40%TiO/sub 2/ coating layer. The wear resistance of Cr/sub 2/O/sub 3/ coating layer was greater than that of Al/sub 2/O/sub 3/-40%TiO/sub 2/ coating layer. Microscopic observation of worn surfaces was made by SEM. SEM observation showed that the main mechanism of wear for Al/sub 2/O/sub 3/-40%TiO/sub 2/ coating layer was abrasive wear under 50 N. For the case of Al/sub 2/O/sub 3/-40%TiO/sub 2/ coating layer, as the surface cracks perpendicular to sliding direction propagated, the wear debris was generated in wear track. However, the main mechanism of wear for Cr/sub 2/O/sub 3/ coating layer was brittle fracture under 150 N.

Sliding Contact Analysis between Rubber Seal, a Spherical Particle and Steel Surface (시일과 스틸면 사이에 구형 입자가 있는 미끄럼 접촉 해석)

  • Park, Tae-Jo;Lee, Jun-Hyuk
    • Tribology and Lubricants
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    • v.28 no.1
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    • pp.1-6
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    • 2012
  • In this paper, a three elastic body sliding contact problem is modeled to investigate more precise wear mechanisms related with the sealing surface. A 3-D finite element contact model, a small spherical elastic particle, PTFE seal and steel surface, is solved using a nonlinear finite element code MARC. The deformed seal and steel surface shapes, von-Mises and principal stress distributions are obtained for different seal sliding distances. The entrapped small particle within PTFE seal results in very high stresses on the steel surface which exceeded its yield strength and produce plastic deformation such as groove and torus. The sealing surface could also be worn down by sub-surface fatigue due to intervening small particles together with the well-known abrasive wear. Therefore the proposed contact model adopted in this paper can be applied in design of various sealing systems, and further studies are required.