• Title/Summary/Keyword: Friction Temperature

Search Result 1,028, Processing Time 0.138 seconds

Influence of the Relative Amount of Graphite and Zirconium Silicate on Friction Characteristics (흑연과 지르콘의 상대적인 함량에 따른 마찰특성에 관한 연구)

  • Kim, Seong-Jin;Jang, Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.166-172
    • /
    • 2000
  • Friction characteristics of phenolic resin-based friction composites containing threedifferent relative amounts of graphite and zirconium silicate were investigated by using a pad-on-disk type friction tester. Constant temperature test and constant interval test at three different initial temperatures(100. 200, 300$^{\circ}C$) were performed to examine the effects of friction heat on friction characteristics at elevated temperature. The friction composite(FMO.7) with higher content of ZrSiO$_4$showed unstable friction force at higher temperature and resulted in larger fluctuations of vibration during friction test. The abrasive action of ZrSiO$_4$in friction composite impeded stable transfer film and induced higher friction heat at friction interface. Friction oscillations according to the temperature were associated with the formation of transfer film(i'd body layer) on the friction composite and the counter part.

  • PDF

A Study of the Friction Characteristics of Plastics on Lubricated Condition (윤활상태에서 플라스틱의 마찰특성에 관한 연구)

  • 강석춘
    • Tribology and Lubricants
    • /
    • v.8 no.1
    • /
    • pp.48-55
    • /
    • 1992
  • The friction characteristic of plastics (PTFE, Nylon, Acetal and phenolic) was studied on the lubricated condition with a pin on disk machine. Mineral oil without additive (base oil) and water were used as liquid lubricants at the controlled temperature. From the experimental work, it was found out that the coefficient of friction of plastics was controlled by the mechanical properities of plastic more than that of liquid for various load and temperature. Viscosity of liquid has affected on the friction only at low temperature under lighb load. Among the tested plastics, the coefficient of friction of PTFE was the lowest under light load and at low temperature while Nylon at medium load and temperature, and Acetal at heavy load and high temperature. The coefficient of friction of soft plastics like PTFE and Nylon were increased as the load and temperature were increased, while that of hard plastic (Acetal) was decreased and that of thermo setting plastic (phenolic) was mixed. Also for soft plastics, the coefficient of friction under heavy load was always higher than that under light load, while hard plastic was vice versa.

Effects of Composition Ratio and Temperature on Friction and Wear of PTFE-Polyimide Composites (PTFE-폴리이미드 복합 재료의 마찰과 마모에 대한 성분비와 온도의 영향)

  • 심현해;권오관;이규한;김병환
    • Tribology and Lubricants
    • /
    • v.12 no.3
    • /
    • pp.55-62
    • /
    • 1996
  • Present study was undertaken to investigate the effects of composition ratio and temperature on the friction and wear of PTFE-polyimide composites under the atmosphere of nitrogen gas. The load range was 0.62-3.46 MPa, and the temperature range was room temperature and 200$^{\circ}$C. To mention some of the notable results, friction coefficient of PTFE 100% varied relatively little within the given load and temperature ranges. Polyimide 100% showed the lowest friction coefficient of 0.06 at 200$^{\circ}$C among all the experiments. PTFE 80%-polyimide 20% showed the lowest wear factors on the whole. Friction coefficient of PTFE 20%-polyimide 80% varied from the highest 0.35 to the lowest 0.09 among all the materials at room temperature, and showed almost the same lowest values with polyimide 100% at 200$^{\circ}$C. Suggestion of friction and wear mechanisms of the materials was tried to explain the observed phenomena including above mentioned results.

The Effect of Metal Fibers on the Tribology of Automotive Friction Materials (마찰재에 함유된 금속섬유와 마찰 특성의 연관관계)

  • Ko, Kil-Ju;Cho, Min-Hyung;Jang, Ho
    • Tribology and Lubricants
    • /
    • v.17 no.4
    • /
    • pp.267-275
    • /
    • 2001
  • Friction and wear properties of brake friction materials containing different metal fibers (Al, Cu or Steel fibers) were investigated. Based on a simple experimental formulation, friction materials with the same amount of metal fibers were tested using a pad-on-disk type friction tester. Two different materials (gray cast iron and aluminum metal matrix composite (MMC)) were used for disks rubbing against the friction materials. Results front ambient temperature tests revealed that the friction material containing Cu fibers sliding against gray cast iron disk showed a distinct negative $\mu$-v (friction coefficient vs. sliding velocity) relation implying possible stick-slip generation at low speeds. The negative $\mu$- v relation was not observed when the Cu-containing friction materials were rubbed against the Al-MMC counter surface. Elevated temperature tests showed that the friction level and the intensity of friction force oscillation were strongly affected by the thermal conductivity and melting temperature of metallic ingredients of the friction couple. Friction materials slid against cast iron disks exhibited higher friction coefficients than Al-MMC (metal matrix composite) disks during high temperature tests. On the other hand, high temperature test results suggested that copper fibers in the friction material improved fade resistance and that steel fibers were not compatible with Al-MMC disks showing severe material transfer and erratic friction behavior during sliding at elevated temperatures.

High temperature Friction and Wear of Friction Material; The Effect of the Relative Amount of Graphite and Zirconium Silicate (ZrSiO$_4$) (흑연과 지르콘의 상대적 함량에 따른 마찰재의 고온 마찰 및 마모특성)

  • Kim, Seong-Jin;Jang, Ho
    • Tribology and Lubricants
    • /
    • v.16 no.5
    • /
    • pp.365-372
    • /
    • 2000
  • Tribological behavior of novolac resin-based friction materials with three different relative amounts of graphite and zirconium silicate was investigated by using a pad-on-disk type friction tester. The goal of this paper is to examine the effects of the relative amount of a lubricant and an abrasive in the automotive friction material on friction and wear characteristics at elevated temperature. Friction and wear of friction materials were affected by the existence of transfer film(3$\^$rd/ body layer) at friction interface and the composition of friction material, especially lubricant amount. The friction material with higher content of graphite indicated homogenized and durable transfer film, and resulted in stable friction coefficient regardless of the increase in friction heat. The experimental result also showed that the higher concentration of ZrSiO$_4$ in friction material aggravated friction stability and wear resistance due to the higher friction heat generated at fiction interface during high temperature friction test.

Heat Transfer Analysis of Friction Welding of A2024 to SM45C (A2024 와 SM45C 마찰용접의 열전달 해석)

  • 이상윤;윤병수
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.10 no.1
    • /
    • pp.65-70
    • /
    • 2001
  • The hear transfer mechanism initiating the friction welding is examined and a transient three dimensional heat conduc-tion model for the welding of two dissimilar cylindrical metal bars is investigated. The cylindrical metal bars are made of materials made of A2024 and SM 45C. Numerical simulations of heat flow are performed using the finite volume method. Respectively. Commercial FLUENT code is used in the heat flow simulation and maximum temperature and distribution of temperature are calculated. Temperature of friction welded joining face is compared with the temperature distribution measured by experiment and numerical simulation. The maximum temperature of friction welded joining face is lower than melting point of A2024-T6 aluminum alloy using insert metal. The temperature distribution of friction welded join- ing face with insert metal is more uniform than that of without inset metal.

  • PDF

Study of Anti-Fading Phenomena during Automotive Braking (자동차 제동시 나타나는 Anti-Fading현상에 관한 연구)

  • Lee, Jung-Ju;Jang, Ho
    • Tribology and Lubricants
    • /
    • v.14 no.1
    • /
    • pp.70-78
    • /
    • 1998
  • Two different friction materials (organic and low-metallic pads) for automotive brakes were studied to investigate the anti-fading phenomena during stop. The anti-fading phenomena were pronounced more in the case of using low metallic friction materials than organic friction materials. The main cause of the anti-fading phenomena was the high dependence of friction coefficient on a sliding speed. The anti-fading was prominent when the initial brake temperature was high in the case of low-metallic friction materials due to the strong stick-slip event at high temperature. On the other hand, the anti-fading was not severe in organic friction materials and the effect was reduced at high braking temperature due to the thermal decomposition of organic friction materials. The strong stickslip phenomena of low metallic friction materials at high temperature induced high torque oscillations during drag test. During this experiment two different braking control modes (pressure controlled and torque controlled modes) were compared. The type of the control mode used for brake test significantly affected the friction characteristics.

Tribology of friction materials containing different metal fibers (마찰재에 함유된 금속섬유의 종류에 따른 마찰 특성)

  • Ko, Kil-Ju;Jang, Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.55-63
    • /
    • 2001
  • Friction and wear properties of brake friction materials containing different metal fibers (Al, Cu or Steel fibers) were investigated using a pad-on-disk type friction tester. Two different materials(gray iron and Al-MMC)) were used for disks rubbing against the friction materials. Results from ambient temperature tests revealed that the friction material containing Cu fibers sliding against cast iron disk showed a distinct negative ${\mu}$-ν (friction coefficient vs. sliding velocity) relation implying possible stick-slip generation at low speed. The negative ${\mu}$-ν relation was not observed when the Cu-containing friction materials were rubbed against the. Al-MMC counter surface. As applied loads increased, friction materials showed higher friction coefficients comparatively. Friction materials slid against cast iron disks exhibited higher friction coefficients than Al-MMC disks during high temperature tests. On the other hand, high temperature test results suggested that copper fibers in the friction material improved fade resistance and the steel fibers were not compatible with Al-MMC disks showing severe material transfer and erratic friction behavior during sliding at elevated temperatures.

  • PDF

Fabrication of Embedded Thermocouple Sensor and Experimental Study on Measurement of Interface Temperature for Dry Friction (임베디드 서모커플 센서 제조 및 미끄럼 마찰 계면온도 측정에 관한 실험적 연구)

  • Jang, Beomtaek;Lim, Youngheon;Kim, Seocksam
    • Tribology and Lubricants
    • /
    • v.29 no.6
    • /
    • pp.372-377
    • /
    • 2013
  • This study investigated the interface temperatures for the sliding friction of three types of pins fabricated with thermocouple wires by the suction casting method. Optical microscopy was used to examine the surrounding material state at the bonding interface with the thermocouple wires. Friction tests were performed under dry sliding conditions against stainless steel 304 at nominal stresses of 1.42-4.25 MPa and sliding speeds of 0.5-1.25 m/s. Tribological data were collected using a custom-made pin-on-disk apparatus that measured the interface temperature and corresponding friction coefficient. Static tests were performed to demonstrate the functionality and reliability of the thermocouple wires-combined temperature sensor (TCTS). Each TCTS showed good linearity and sensitivity and very similar response times for the thermocouple and critical temperature during sliding friction.

Development of Wear Equation according to Friction Coefficient and Temperature using a Dual Leaf-Spring in the Sliding Test (판스프링을 사용한 마모실험에서 마찰계수와 마찰온도를 고려한 마모식의 개선)

  • Kim, Jung-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.5 no.1
    • /
    • pp.19-26
    • /
    • 2006
  • The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a dual leaf-spring. The materials of the specimens are used as ten kinds along their hardness. In this study, both upper and lower specimens have been used the same materials. Using experimental data, we figured the relationship between wear coefficient and friction coefficient, and the relationship between wear coefficient and friction temperature. Also we combined friction temperature and friction coefficient instead of wear coefficient. We substituted this into wear equation of Archard. The result had been derived a newly wear equation in using dual leaf-spring wear system.

  • PDF