• Title/Summary/Keyword: Wear Mechanism

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A Study on Wear Properties of Plasma Sprayed $Cr_3C_2$-NiCr Coating at High Temperature (크롬탄화물 용사피막의 고온마모 특성연구)

  • 김의현;권숙인
    • Journal of Welding and Joining
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    • v.11 no.4
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    • pp.91-102
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    • 1993
  • The plasma sprayed $Cr_3C_2$-NiCr coatings are widely used as wear-resistant and corrosion-resistant materials. The mechanical and wear properties of the plasma sprayed $Cr_3C_2$-NiCr coating on steel plate were examined in this study. The pore in the coatings could be classified into two types, the one is the intrinsic pore originated from the spraying powder, the other is the extrinsic pore formed during spraying. During the tensile adhesion test, the fracture occured at the interface of top coating and bond coating. It is though that the compressive residual stress increases with the increase of the top coating thickness. From the wear test, it was found that the wear rate increased with the increase of the sliding velocity regardless of the temperature. It is thought that the fracture toughness reduces with the increase of the sliding velocity at $30^{\circ}C$ and that the adhesion amount increases with the increase of the sliding velocity at $400^{\circ}C$ It is concluded that the wear mechanism at $30^{\circ}C$ is the fracture and pull-out of the carbide particles due to the fatigue on sliding surface, while the wear mechanism at $400^{\circ}C$ is the adhesion of the smeared layer formed during wear process.

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Wear Mechanism of CrN Coating on Aluminum Alloys Deposited by AIP Method

  • Kim, Seock-Sam;Suh, Chang-Min;Murakami, Ri-ichi
    • KSTLE International Journal
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    • v.3 no.1
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    • pp.43-48
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    • 2002
  • Dry sliding wear and friction test of CrN coaling on two types of aluminum alloy substrates,6061 Al and 7075 Al deposited by arc ion plating, was peformed with a ball-on-disk tribometer. The effects of normal Bead and the mechanical properties of substrate on the friction coefficient and wear-resistance of CrN coating were investigated. The worn surfaces were observed by SEM. The results show that surface micro-hardness of CrN- coated 7075 Al is higher than that of CrN-coated 6061 Al. With an increase in normal lead, wear volume increases, while the friction coefficient decreases. The friction coefficient of CrN-coated 6061 Al is higher than that of CrN-coated 7075 Al, while the wear-resistance of CrN-coated 6061 Al is lower than the CrN-coated 7075 Al's, which indicates that the substrate mechanical properties have strong inf1uences on the friction coefficient and wear of CrN coating. The main wear mechanism was fragments of CrN coating, which were caused by apparent plastic deformation of substrate during wear test.

A study on Adhesion and Wear Resistance of Vanadium Carbide Coating on Die Steels by Immersing in Molten Borax Bath (용융 붕사욕 침지법에 의해 금형용 강에 형성된 VC coating층의 밀착성과 내마모성에 관한 연구)

  • Lee, B.K.;Nam, T.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.2
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    • pp.71-84
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    • 2000
  • A study on adhesion and wear resistance of VC(vanadium carbide) coating on die steels, STD11 and STD61, has been carried out. The VC coating on the die steels was made by immersing them in molten borax bath, a kind of TRD(thermo-reactive deposition and diffusion). Adhesion strength and wear resistance were investigated using scratch test, indentation test and plate-disc test(Ogoshi type) respectively. The influence of sliding distance on the amount of wear has been determined and dominant wear mechanisms has been characterized using optical microscopy, scanning electron microscopy and EDS spectroscopy. The critical adhesion strength($L_c$) between VC coating layer and substrate(STD11) was increased to 60N($L_c$) in the scratch test. In the case of STD61, the strength increased to 24N. The wear resistance of VC coated die steels was excellent because the diffusion layer formed just below the coating layer. The dominant wear mechanism was identified as adhesive wear for VC coating die steels which were worn by combination of cracking and plucking of VC fragments and disc.

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A Study on the Wear Characteristics of Austempered Ductile Cast Iron in Corrosive Environments (오스템퍼링한 구상점연주철의 부식환경중의 마멸특성에 관한 연구)

  • Kang, Myug-Soon;Jun, Tae-Ok;Park, Heung-Sik;Jin, Dong-Gyu
    • Journal of Ocean Engineering and Technology
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    • v.2 no.2
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    • pp.87-95
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    • 1988
  • This paper is studied to know corrowive wear characteristics of austempered ductile cast ironin corrosive environments against mating SM45C hardened two test pieces in distilled water and NaCl aqueous solution. The corrosive wear mechanism was investigated by scanning electron microscopy and retained austenite volume fraction was investigated by X-ray diffractometer. The experimental result show that the corrosive wear characteristics depend largely on the $\textrm{Fe(OH)}_{3}$which is influenced by the critical sliding distance $L_{cr}$ and $L_{cr}$ shorted with increasing NaCl concentration. It was found that the carbides in matrix have a significant effect on their corrosive wear resisance and the fine acicular bainite showed corrosive wear resistance stronger than that of the coarse acicular and platelet bainite. From above results the model of corrosive wear mechanism in corrosive environments is proposed.

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Analysis of Wear Behaviour Corresponding to Contact Shape in High Temperature and High Pressure Environment (고온고압수중에서 접촉형상에 따른 마멸거동 분석)

  • Song Ju-Sun;Kim Hyung-Kyu;Lee Young-Ho;Kim Jae-Hoon
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2004.11a
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    • pp.31-36
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    • 2004
  • In this paper, fretting wear tests were conducted in air at room temperature (RT) and in water at high temperature and high pressure (HTHP) environment to analyze the wear characteristic. As for the supporting condition between the tube and spring/dimple, the gap of 0.2 mm in air at RT and the normal force of 10 N and the slip of $50\;{\mu}\;m$ in water at HTHP were applied. Four different shapes of spring/dimple specimen (type A, B, C, D) were used. Detail eaxamination of wear scar was also performed using SEM micrographs. As a result, in the case of the spring of truncated wedge, severer wear occurs than the others. Protrusion part was found and larger in air at RT. It is thought that the difference in the wear volume and the protrusion is caused by the different wear mechanism corresponding to the different environment.

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Contact Analysis between Rubber Seal, a Spherical Wear Particle and Steel Surface (시일과 스틸면 사이의 구형 마멸입자에 의한 접촉해석)

  • Park, Tae-Jo;Yoo, Jae-Chan;Jo, Hyeon-Dong
    • Tribology and Lubricants
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    • v.24 no.6
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    • pp.297-301
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    • 2008
  • In many dynamic seals such as lip seal and compression packings, it is well known that wear occur at the surface of heat treated steel shaft as results of the intervened wear particle. It is widely understood that the dominant wear mechanism related in sealing surfaces is abrasive wear. However, little analytical and experimental studies about this problems have been done until now. In this paper, a contact analysis is carried out using MARC to investigate the wear mechanism in contact seal applications considering elastomeric seal, a elastic perfect-plastic micro-spherical particle and steel surface. Deformed seal shapes, contact and von-Mises stress distributions for various particle sizes and interference are showed. The maximum von-Mises stress within steel shaft was exceeded its yield strength and plastic deformation occurred at steel surface. Therefore, the sealing surface can be also worn by sub-surface fatigue due to wear particles together with well known abrasion. The numerical methods and models used in this paper can be applied in design of dynamic sealing systems, and further intensive studies are required.

Effects of Counterpart Materials on Wear Behavior of Thermally Sprayed STS316 Coatings (STS316 용사코팅층의 마모거동에 미치는 상대마모재의 영향)

  • Lee, Jae-Hong;Kim, Yeong-Sik
    • Journal of Power System Engineering
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    • v.18 no.6
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    • pp.58-63
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    • 2014
  • This paper deals with the effects of counterpart materials on the wear behavior of thermally sprayed STS316 coatings. STS316 powders were flame-sprayed onto a carbon steel substrate. Dry sliding wear tests were performed using the applied loads of 15 N. AISI52100, $Al_2O_3$, $ZrO_2$ and $Si_3N_4$ balls were used as counterpart materials. Wear behavior of STS316 coatings against different counterpart materials were studied using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that the wear behavior of thermally sprayed STS316 coatings strongly depends on the type of counterpart material. Dominant wear mechanism was similar for all studied materials as failure of adhesion film except for Si3N4 used as counterpart material. In the case of Si3N4 used as counterpart material, dominant wear mechanism was abrasion.

Effect of TiC and AlN on the Wear Behavior and Mechanical Properties of Hypereutectic Al-Si Alloys (과공정 Al-Si 합금의 마모 거동과 기계적 성질에 미치는 TiC와 AlN의 영향)

  • Ju, Seung Hwan;Choi, Jin Myung;Kim, Yong Jin;Park, Ik Min;Park, Yong Ho
    • Korean Journal of Metals and Materials
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    • v.48 no.11
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    • pp.1003-1008
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    • 2010
  • In this study, the effect of the reinforcement on the wear behaviour and mechanical properties of hypereutectic Al-Si alloys was investigated. The Gas atomized hypereutectic Al-20Si alloy powders were mixed with 1, 3, and 5 wt.% AlN and TiC ceramic particles and consolidated by hotpress. The Al-20Si powder has both finely dispersed primary Si phases and eutectic structures. The Al-20Si-AlN, TiC composites showed that the reinforcements were distributed along the boundary of the Al-20Si alloy. The UTS increased with increasing the AlN, TiC contents. At a lower load, with an increasing weight fraction of reinforcements, the wear rate decreased in both composites and the wear mechanism was adhesive wear. At a higher load, the shape of the debris changes the mechanism of the AlN composites to abrasive-adhesion wear and this resulted in an increase of the wear rate.

A Study on the Effect of physico-chemical Factors in Wear Mechanism in a Lubricated Concentrated Contact (II) (윤활시스템에서 마모메카니즘에 미치는 물리화학적 영향에 관한 연구(II))

  • 최웅수;권오관;문탁진;유영흥
    • Tribology and Lubricants
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    • v.4 no.1
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    • pp.43-55
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    • 1988
  • A Study on the effect of the additives in lubricating oil was investigated on the basis of the thermal activated wear theory in terms of their wear behaviours, using four ballwear machine. The sample oils, which included diethyl-3, 5-di-t-butyi-4-hydroxy-benzyl phosphonate (DEP), ZDDP and TCP additives respectively, showed distinct wear characteristics depending upon the bulk oil temperature and the sliding velocity. The newly synthesized additive, viz., DEP showed excellent antiwear performance cornpared with the conventional additives, ZDDP and TCP. On the basis of the experimental results, it is reduced that the wear mechanism of the conventional additives, viz., ZDDP and TCP is the protective film formation and their antiwear capability is depending upon the shearing strength of the film formed. On the other hand, the new additive, DEP showed that the secondary activation energy was much eliminated and so, the thermal instability was reduced by the hydrogen scavenging reaction of the new additive, which was virtually an endothermic reaction process.In conclusion, a new concept of antiwear mechanism is estabilished and testified. And new chemical, which showed the function of hydrogen and free radical scavenging role, is synthesized and introduced as the new, highly antiwear effective lubricating oil additive.