• Title/Summary/Keyword: High Temperature Test

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Degradation Characteristics of Filament-Winding-Laminated Composites Under Accelerated Environmental Test (필라멘트 와인딩 복합적층재의 환경가속 노화시험 평가)

  • Kim, Duck-Jae;Yun, Young-Ju;Choi, Nak-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.3 s.258
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    • pp.295-303
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    • 2007
  • Degradation behaviors of filament-winded composites have been evaluated under the accelerated environmental test of high temperature, water immersion and thermal impact conditions. Two kinds of laminated composites coated by an urethane resin have been used: carbon-fiber reinforced epoxy(T700/Epon-826, CFRP) and glass-fiber reinforced phenolic (E-glass/phenolic, GFRP). For tensile strength of $0^{\circ}$ composites, CFRP showed little degradation while GFRP did high reduction by 25% under the influence of high temperature and water However for water-immersed $90^{\circ}$ composites tensile strength of both CFRP and GFRP showed high reduction. Bending strength and modulus of $90^{\circ}$ composites were largely reduced in water-immersion as well as high temperature environment. Urethane coating on the composite surface improved the bending properties by 20%, however hardly showed such improvement for water-immersed $90^{\circ}$ composites. In case of shear strength and modulus, both CFRP and GFRP showed high reduction by water-Immersion test but did a slight increase by high temperature and thermal impact conditions.

Quality Assessment of Domestic Non-automatic Weighing Instruments for International Standards (국제표준에 대비한 국내 비자동저울의 품질평가에 관한 연구)

  • Namkoong Chai-Kwan;Kong Jae Hyang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.6
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    • pp.127-134
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    • 2004
  • As the result of reduction of the barrier of national economy on matters of quality assurance of weighing instruments in recently, it is considering in domestic as well as international matters. Therefore, this study is to analysis and compare with international md national measuring standards on the electric self-indicating scale, to improve the quality of electronic machine by providing a reformation plan on currently problems of domestic manufactured, and to identify to introduce in domestic criteria from international standards. I had compared KSC 1313 to OIML R 76-1 as the performance assessment items, such as metrology Properties test, static temperature test, temperature effect testing under the un-load, electronic wave disturbance test, high-tempereature and high-humidity stability test and durability test. Therefore, only one company is passed all items of the test according to the international (reference) standards, but it is possible to improve the quality in general if it should be use the load cell and electric components which is stability of temperature change in order to supplementation to the static temperature test and temperature effect testing under the un-load. It is also possible to apply in the domestic with the OIML 76-1 after correcting the design.

Experiment for the Improvement of Fire Resistance Capacity of Reinforced Concrete Flexural Member Strengthened with Carbon Fiber Reinforced Polymer (CFRP로 보강된 철근콘크리트 휨부재의 내화성능 개선을 위한 실험)

  • Lim, Jong-Wook;Seo, Soo-yeon;Song, Se-Ki
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.33 no.12
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    • pp.19-27
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    • 2017
  • This paper is a study to improve the fire-resistance capacity of reinforced concrete (RC) members strengthened by fiber-reinforced-polymer (FRP). The fire resistance of the RC members strengthened by FRP was evaluated through high temperature exposure test. In order to improve the fire resistance of the FRP reinforcing method, a fire-proof board was attached to the reinforced FRP surface and then the high temperature exposure test was carried out to evaluate the improvement of the fire resistance performance. It was confirmed that the resistance to high temperature of NSMR could be improved somewhat compared with that of EBR from the experiment that exposed to high temperature under the load corresponding to 40% of nominal strength. When 30 mm thick fire-resistance (FR) board is attached to the FRP surface, the surface of the reinforced FRP does not reach $65^{\circ}C$, which is the glass transition temperature (GTT) of the epoxy until the external temperature reaches $480^{\circ}C$. In particular, when a high performance fire-proof mortar was first applied prior to FR board attachment, the FRP portion did not reach the epoxy glass transition temperature until the external temperature reached $600^{\circ}C$.

Sliding We3f Properties for 5%Co-5%V-1%Nb High Speed Steel by Powder Metallurgy at High Temperature (5%Co-5%V-1%Nb 분말고속도공구강의 고온 미끄럼마모특성)

  • 이한영;김용진;배종수
    • Tribology and Lubricants
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    • v.19 no.3
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    • pp.151-158
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    • 2003
  • In metal cutting at the tool-chip interface, friction generates considerable amount of heat. Thus, the knowledge of wear properties of cutting tool material in high temperature has been as one of important factors in need of clarification. The authors presented the wear properties of 5%Co-5%V-1%Nb high speed steel, fabricated by powder metallurgy, in room temperature in previous articles. The objective of this paper is to clarify the effects of temperature on its wear properties. Wear tests in sliding conditions under various temperatures have been conducted using the pin-on-disc type wear test machine. The results indicate that the wear properties of 5%Co-5%V-1%Nb high speed steel in high temperature as well as in room temperature are excellent. It may be deduced that the oxide layer formed on worn surface at high temperature is stable enough to prevent wear due to the high temperature strength of its matrix.

Characteristics of Dynamic Shear Modulus Mastercurve of Aged or Unaged Asphalt Binders (동전단 마스터곡선을 이용한 아스팔트 바인더의 노화 특성 평가)

  • Yun, Tae Young;Ham, Sang Min;Yoo, Pyeong Jun
    • International Journal of Highway Engineering
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    • v.15 no.1
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    • pp.87-94
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    • 2013
  • PURPOSES: To characterize the aging effect on asphalt binder, dynamic shear modulus mastercurve of two typical asphalt binders are developed. METHODS: To develop dynamic shear modulus mastercurve, dynamic shear modulus at high temperature and creep stiffness at low temperature are measured by temperature sweep test and bending beam rheometer test, respectively. RESULTS: It is observed that the aging effect on asphalt binder can be clearly observed from dynamic shear modulus mastercurve and the mastercurve can be utilized to predict behavior of asphalt binder at wide range of temperature. CONCLUSIONS: It is confirmed that SBS 5% modified binder has more desirable mechanical property at low and high temperature as a pavement material comparing to PG64-22 binder and the mastercurve is an effective tool to evaluate the property of asphalt binder.

Managing method for stud female threads used long period under high temperature on the power plants (장기간 사용된 발전설비용 고온 스터드 암나사부 관리방법)

  • Chung, Nam-Yong;Kim, Moon-Young
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.199-205
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    • 2000
  • The stud female threads for stud bolts tend to degrade faster by high temperature over 450 C. Therefore, inspection for replacement cycle of stud bolts is used to carry out many kinds of method such as ultrasonic test(UT), magnetic test(MT), wobble test, visual test and hardness test. The visual inspection among those has been only applied for stud female threads generally and wobble test is often used to apply stud bolts. In this paper, wobble test is applied for evaluation of stud female threads on the contrary stud bolts especially. It is also applied three types of inspection method included wobble test on the two sites which is used for each other different operation cycle and three kinds of acquisition data are compared with evaluation methods. From the results, we have studied the characteristic exchanging of integrity evaluation data distribution according to using time and proposed managing method for female thread of stud on the power plants.

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Relationship between Creep Characteristic Values and Rupture time in STS304 Stainless Steels (스테인리스강의 크리프 특성치와 파단시간과의 관계)

  • KONG YU-SIK;KIM SEON-JIN;LEE BAE-SUB
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.11a
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    • pp.228-233
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    • 2004
  • The characteristics of the probability distribution for mechanical properties, e.g. tensile strength, reduction of area ana elongation, for STS304 stainless steel in elevated temperature were investigated from tensile test performed by constant cross head speea controls with 1mm/min, Recently, in order to clarify the strengthening mechanisms at high temperature, a new scheme to improve high temperature mechanical properties is desired. Therefore, the test ,technique development of high temperature creep behaviors for this material is very important. In this paper, the creep praperties and creep life prediction by Larson-Miller parameter method for STS304 stainless steel to be used for other high temperature components were presented at the elevated temperatures of 600, 650 and $700^{\circ}C$.

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A Study on the Temperature Characteristics of High Voltage Power Cable for Hybrid Electric Vehicle (하이브리드 자동차용 고압 케이블의 온도 특성에 관한 연구)

  • Lee, Ki-Yeon;Kim, Dong-Woo;Kim, Dong-Ook;Gil, Hyoung-Jun;Kim, Hyang-Kon;Choi, Chung-Seog
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.3
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    • pp.338-342
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    • 2008
  • Hybrid Electric Vehicle(HEV) is driven by an internal-combustion engine and an electric motor. It is a combination of an internal-combustion engine and several electrical equipments which use a high voltage battery, an electric motors, an inverter and others. But there is not any separate detailed enforcement regulations for high voltage electric appliances in the existing vehicle-related safety standards. So, test standards suggestion as well as test technique development need to be done for ensuring electrical safety, for an electric motor, a high voltage battery, a(n) inverter/converter and an electric power transmission units and other equipments to ensure the safety of high voltage electric appliances which is the HEV key electrical component. In this paper, We are to provide helpful data to support test technique development and test standard establishment for HEV design and electrical safety security by the following methods; by measuring the voltage, the electric current, and the frequency of HEV, by analyzing electrical characteristics of high voltage electric appliances, and by analyzing temperature characteristics of the electrical current among the analyzed electrical characteristics by thermal imagining cameras.

The High Temperature Oxidation Behavior of Diffusion Aluminized MarM247 Superalloy

  • Matsunaga, Yasuo;Matsuoka, Akira;Nakagawa, Kiyokazu
    • Corrosion Science and Technology
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    • v.2 no.1
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    • pp.53-57
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    • 2003
  • The MarM247 based superalloy (8wt.%Cr- 9wt.%Co- 3wt.%Ta- 1.5wt.%Hf- 5.6%wt.Al- 9.5wt.%W- Bal. Ni) specimens were diffusion aluminized by for types of pack cementation methods, and their coating structure and their high temperature oxidation resistance were investigated. The coated specimens treated at 973K in high aluminum concentration pack had a coating layer containing large hafunium rich precipitates, which were originally included in substrate alloy. After the high temperature oxidation test in air containing 30 vol.% $H_2O$ at 1273K ~ 323K, the deep localized corrosion which reached to the substrate were observed along with these hafnium rich precipitates. On the other hand, the coated specimens treated at 1323K using low aluminum concentration pack showed the coating layer without the large hafunium rich precipitates, and after the high temperature oxidation test at 1273K for 1800 ksec, it did not show the deep localized corrosion. The nickel electroplating before the aluminizing forms thick hafnium free area, and its high temperature oxidation resistance were comparable to platinum modified aluminizing coatings at 1273K.

High Temperature Compressive Properties of Tungsten Activated Sintered Pare Prepared by 0.4 wt.% Ni-doped Tungsten Powder Compacts (0.4 wt% Ni을 첨가한 W 활성소결체의 고온압축 특성 연구)

  • 이승익;김순욱;박영삼;문인형
    • Journal of Powder Materials
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    • v.9 no.5
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    • pp.307-314
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    • 2002
  • The high temperature deformation behavior of the activated sintered W powder compacts was investigated. The W compact showed the relative density of 94% with the average W grain size of $23\mutextrm{m}$ by activated sintering at $1400^{\circ}C$ for 1 hour. Compression tests were carried out in the temperature range of $900-1100^{\circ}C$ at the strain rate range of $10^{0}$/sec - $10^{-3}$/sec. True stress-strain curve and microstructure exhibited the grain boundary brittleness which was dependent on the compression test temperature. The activated sintered W compact showed that the maximum stress as well as the strain at the maximum stress was abruptly decreased as the test temperature increase from $900^{\circ}C$ to 1000 and $1100^{\circ}C$ regardless of the strain rate. The discrepancy of the microstructure in the specimen center was obviously observed with the increase of the test temperature. After compression test at $900^{\circ}C$ the W grain was severely deformed normally against the compression axis. However, after compression test at $1000^{\circ}C$ and $1100^{\circ}C$ the W grain was not deformed, but the microcrack was formed in the W grain boundary. The Ni-rich second phase segregated along the W grain boundary could be partly unstable over $900^{\circ}C$ and affect the poor mechanical property of the activated sintered W compact.