STACIR/AW 410SQmm 가공송전선의 경년열화와 이도거동(III)

김상수,김병걸,신구용,이동일,민병욱,Kim Shang-Shu,Kim Byung-Geol,Sin Goo-Yong,Lee Dong-Il,Min Byung-Uk 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.3

As a way to expand electric capacity in conductor with electric power demand, STACIR/AW (Super Thermal-resistant Aluminum-alloy Conductors Aluminum-clad Invar-Reinforced) conductor which has high electric current and heat resistance characteristics have been developed. STACIR/AW power line is mechanical composite wire composed of steel cores for dip control and aluminum conductors for sending electric current. Recently, to ensure stable operation and prediction of wire life span of STACIR/AW conductor, a heat property of STACIR/AW conductor have been investigated. In the present work, a change of essential property with long term-heat exposure of STACIR/AW conductor and its structure material, INVAR wire and Al conductor, have been investigated. INVAR/AW is approximately $3.2\;{\mu}m/m^{\circ}C$. thermal expansion coefficient of INVAR/AW wire increases with time of heat exposure. the thermal expansion coefficient of INVAR/AW is markedly influenced by heat and mechanical treatment. creep rate(0.242) of STACIR/AW $410\;mm^2$ conductor at room temperature is much higher than that(0.022) at $210\;^{\circ}C$ STACIR/AW $410\;mm^2$ conductor has minimum creep rate at operating temperature. To lower creep rate with increase temperature is more unique characteristics in STACIR/AW. It is expected that STACIR/AW turned its tension to INVAR/AW at the transition temperature. at room temperature, the tension apportionment of INVAR/AW in STACIR/AW is about $50\;\%$. but whole tension of STACIR/AW is placed on the INVAR/AW alone of core metal above transition temperature.

Invar 36 합금 선재의 미세조직에 미치는 냉간 인발 및 열처리 공정의 영향

한승엽 ( seung Youb Han ),장선아 ( Seon Ah Jang ),은희철 ( Hee-Chul Eun ),최정훈 ( Jung-Hoon Choi ),이기락 ( Ki Rak Lee ),박환서 ( Hwan Seo Park ),안도희 ( Do-Hee Ahn ),김수영 ( Soo Young Kim ),김재열 ( Jea Youl Kim ),신상용 ( San 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.10

In this study, the effect of cold drawing and heat treatment on the microstructure of Invar36 alloy wire was investigated. Invar36 alloy wire is used as a transmission line core material, and is required to have high strength. The diameter of the Invar36 alloy wire specimens were reduced from 16 mm to 4.3 mm after three cold drawing and two heat treatment processed, thereby increasing tensile strength. Specimens were taken after each of the cold drawing and heat treatment processes, and their microstructure and tensile properties were analyzed. The Invar36 alloy γ-(Fe, Ni) phase matrix before the cold drawing and heat treatment processes. After the cold drawing processes, {220} and {200} textures were mainly achieved. After the heat treatment processes, a {220} recrystallization γ-(Fe, Ni)phase was formed with fine carbides. The recrystallization γ-(Fe, Ni) phase grains had low dislocation density, so they probably accommodated a large amount of deformation during the cold drawing processes.

Invar 레이저 용접부의 인장 및 피로강도 평가

김성민,곽명섭,이희근,윤광희 대한용접·접합학회 2021 대한용접학회 특별강연 및 학술발표대회 개요집 Vol.2021 No.11

No.96 type LNG 운반선은 1차 방벽과 2차 방벽 모두 Invar를 사용하는 membrane형 화물창으로, Invar의 용접과 품질관리가 화물창 제작을 위한 핵심적인 기술이다. 그 중 현재 저항 심용접(RSW, Resistance Seam Welding)을 사용하는 3겹 Invar의 Edge joint가 No.96 type 화물창 용접의 80% 이상을 차지하며, 3겹 edge joint의 생산성은 LNG 화물창 제작 생산성과 직결된다. 기존 RSW를 성능을 향상시켜 생산성을 높이는 방향은 여러가지 기술적인 문제로 인해 획기적인 생산성 향상을 기대하기 어렵다. 따라서 Edge joint의 용접 속도 향상과 안정적인 용접 품질 확보를 위하여 LNG 화물창 제작을 위한 레이저 용접 기술의 개발이 필요하다. LNG 화물창 제작을 위한 레이저 용접의 적용은 Edge joint 뿐만 아니라 LNG 화물창 내의 다른 이음부에도 적용할 수 있을 것이며, 이를 위해서 용접 기법 및 용접부 강도에 대한 체계적인 연구가 필요하다 본 연구에서는 기존의 RSW 대비 2배 이상의 높은 속도로 용접된 Invar 레이저 용접부의 인장 및 반복 변위 하에서의 거동 특성을 대해 실험적으로 평가하였다. 또한 기존의 RSW의 동일한 joint에서의 실험 결과와 비교하여 레이저 용접을 통한 edge joint에서의 파단 양상 및 파단 시의 하중 혹은 수명을 비교하였다.

콜타르피치를 이용한 Invar 합금 위 탄소나노튜브의 합성

김준우(Joon-Woo Kim),정구환(Goo-Hwan Jeong) 한국표면공학회 2017 한국표면공학회지 Vol.50 No.6

We report the growth of carbon nanotubes (CNT) on Invar-42 plates using coal tar pitch (CTP) by chemical vapor deposition (CVD) method. The solid phase CTP is used as an inexpensive carbon source since it produces a bunch of hydrocarbon gases such as CH₄ and other CxHv by thermal decomposition over 450℃. The Invar-42 is a representative Ni-based ferrous alloy and can be used repetitively as a substrate for CNT growth because Ni and Fe are used as very active catalytic elements. We changed mixing ratio of carrier gases, argon and hydrogen, and temperature of growth region. It was found that the optimum gas ratio and temperature for high quality CNT growth are Ar:H₂ = 400:400 sccm and 1000℃, respectively. In addition, the carbon nanoball (CNB) was also obtained by just changing the mixing ratio to Ar:H₂ = 100:600 sccm. Finally, CTP can be employed as a versatile carbon source to produce various carbon-based nanomaterials, such as CNT and CNB.

경년열화가 가공송전선(STACIR/AW)용 강심소재 Al Clad Invar 강선의 피로에 미치는 영향 ( 1 )

김상수,김병걸,현석규,신구용,이동일,민병욱,Kim Shang-Shu,Kim Byung-Geol,Hyun Suk-Kyu,Sin Goo-Yong,Lee Dong-Il,Min Byung-Uk 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.1

Fatigue properties of INVAR/AW wires have been investigated under the heat exposure in order to ensure stable operation and to estimate life span of their power line. In the case of heat exposure for 10000 hr, fatigue life and limit increased. For further heat exposure, fatigue limit decreased due to the decrease in yield strength. The variation fatigue of strand wire was strongly dependent on its amplitude. Also, cracks in wires of 7 strands were caused by stress concentration at the outer surface and fretting between each wire during vibration.

경년열화가 증용량 저이도 송전선의 기계적특성에 미치는 영향 (II)

김상수,김병걸,신구용,이동일,민병욱,Kim Shang-Shu,Kim Byung-Geol,Sin Goo-Yong,Lee Dong-Il,Min Byung-Uk 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.1

Today, restricted energy sources, environmental considerations and the high cost of transporting fuel have limited the number and location of available power plant sites. The pressures resulting from these conditions have tended to require the construction of long, high-capacity, high-voltage power lines. it's used to adapt to STACIR/AW(Super Thermal-resistant Aluminum alloy Conductors, aluminum-clad Invar-Reinforced) conductor for coping with these situations. STACIR/AW conductor was formed by the combination of INVAR/AW as the core for low sag and super thermal-resistant aluminum alloy conductor for current capacity increase. increase of temperature by current capacity and long span lines make the susceptible to the deterioration of thermo-mechanical properties(conductivity, tensile strength, E-modulus and twist property et al). In the present work, changes of thermo-mechanical properties with aging have been studied in STACIR/AW $410 mm^2$ conductor with forms of single wire and strand wire.

인바스타프의 검측 실험

이승준(Lee, Seung Jun),윤홍식(Yun, Hong Sic),장민수(Jang, Min Soo) 한국측량학회 2014 한국측량학회 학술대회자료집 Vol.2014 No.4

전본 연구는 Invar Staff검측기를 이용하여 디지털레벨의 정밀한 수준측량을 목적으로 하여 수행되었다. 실제 작업장에서 편의를 위해서 한 사람이 Invar Staff를 중앙을 어깨에 메고 이동하는 것을 확인하였고, 이때에 Invar Staff의 휨으로 인하여 표척 읽음 값에 오차가 발생할 수 있다. 또한 Invar Staff 관리 부주의 및 노후로 인하여 예상하지 못하는 측정 결과가 나올 수 있다. Invar Staff의 정밀한 검측을 위하여 디지털 레벨, 레이저거리측정기, MPJ092 모터를 이용하였다. In this study, was conducted for the purpose of accurate level measurement of digital level using the Invar Staff inspection machine. There is a case to make sure that one person moves in play to shoulder the center Invar Staff for convenience in the workplace of fact, an error occurs in the Invar Staff opening value due to bending of the Invar Staff at that time. Also, it is possible measurement results by aging or Invar Staff management inadvertent unexpected comes out. Invar Staff to the inspection of the precise digital level, laser distance meter, MPJ092 motor was used.

Stabilization of FCC phase using Mn incorporation in nanograin Invar alloy foils fabricated by electroforming

HoonKee Park,Tae Hyung Lee,Sol A. Lee,In-Ho Jung,Ho Won Jang 대한금속·재료학회 2020 ELECTRONIC MATERIALS LETTERS Vol.16 No.2

Invar alloys have been widely used recently due to their extremely low coeffi cients of thermal expansion (CTE). The developmentof thin Invar alloy foils is essential for widespread use in the industry such as a shadow mask, fl exible display, and wearabledevices. Traditional Invar alloy fabrication process like rolling has fatal disadvantages in obtaining thin fi lms. Electroforminghas emerged as an important approach to overcome the current problem in terms of cost and thickness. However, till date,electroformed Invar alloys have BCC–FCC mixed phases and relatively high CTE due to nanoscale grain size. In this study,we incorporate Mn to the nanograin Invar alloy foils by electroforming process to stabilize the FCC phase, assisted by thermodynamicexpectation using FactSage. As the amount of Mn increases, the CTE decreases. Although electroformed Fe–Ni–Mnalloys have a relatively high CTE than conventional Invar alloys because it still has nanograins, the CTE could be further reducedby recrystallization process. Our results show that the incorporation of Mn into Invar alloys can stabilize the FCC phase nearthe room temperature, and electroforming is promising to replace the conventional rolling process for thin metal foils.

Shadow Mask용 인바 합금의 특성 연구

鄭又暢,李泰昊,金成俊 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.5

Invar alloy has been extensively used for shadow mask of color television and computer monitor because of its low thermal expansion coefficient, but the processing technologies of invar alloys for shadow mask have not been well known. To find out the unknown manufacturing process of invar alloys for shadow mask, variations in mechanical properties with cold reduction ratio and annealing temperature were investigated. Also, the relationships between etching properties and texture in invar alloys were investigated by applying the newly developed texture analysis technique, EBSD. The final cold reduction ratio in the invar alloys was found to be about 25 percent while the cold reduction ratio above 60 percent was needed for the good etching properties in the low carbon Al-killed steel. It was suggested that because {001} grains in the surface of invar alloys had high angle grain boundaries, the more the uniform-distributed {001} grains in the surface, the etchability was improved. When the cold-rolled invar alloys were annealed, the etchability was deteriorated by both more inhomogeneous distribution of coarse {001} recrystallized grains and the increase in high angle grain boundaries with misorientations above 40˚

펄스 전압을 이용한 인바 합금의 미세 전해가공

김원묵(W. M. Kim),백승엽(S. Y. Baek),이은상(E. S. Lee),탁용석(Y. S. Tak) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월

Invar is a compound metal of Fe-Ni system and contain 36% Ni. The most distinction characteristic of Invar is the coefficient of thermal expansion is 1.0 × 10??/℃ That is a tenth of general steel material. This low thermal expansion characteristic of Invar is applied to the missile, aircraft, monitor CRT and frontier display"s shadow mask such as FED and OLED. The usage of the Invar shadow mask for display is increasing due to the requirement of larger size and flatness monitor. The Invar shadow mask is machined by two ways electro-forming and laser now. However the electro-forming takes a too long time and the laser machining is accompanied with Burr. In this study, PEMM(pulse electrochemical micro machining) is conducted to machine the micro hole to the Invar and ø80㎛ hole was machined.