• Title/Summary/Keyword: steel coil

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Evaluation of the Integrity of TIG Welding Using Non-Contact SH-EMAT (비접촉 SH-EMAT을 이용한 TIG용접부 건전성 평가)

  • Park, Tae Sung;Park, Yeong Hwan;Park, Ik Keun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.1
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    • pp.48-53
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    • 2016
  • An EMAT can be used to reliably detect defects as it serves as a non-contact transducer with the ability to transmit ultrasonic waves into specimens without couplant. Moreover, an EMAT can easily generate desired waves by altering the design of the coil and magnet. This study proposes an SH-EMAT to evaluate the integrity of the TIG welding part. A stainless steel was welded using the TIG welding method. The welding current was varied to create artificial defects. Both the PA-UT and the RT were applied to verify the defect size. The experimental results generated by using the EMAT were compared with those methods. The amplitude was observed to decrease with an increase in the defect size. These results confirmed that the presence of defects can be reliably detected by attenuation of signal amplitude. The results demonstrated that the proposed method is suitable for evaluating the integrity of TIG welding.

Bluetooth Low-Energy Current Sensor Compensated Using Piecewise Linear Model

  • Shin, Jung-Won
    • Journal of Sensor Science and Technology
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    • v.29 no.5
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    • pp.283-292
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    • 2020
  • Current sensors that use a Hall element and Hall IC to measure the magnetic fields generated in steel silicon core gaps do not distinguish between direct and alternating currents. Thus, they are primarily used to measure direct current (DC) in industrial equipment. Although such sensors can measure the DC when installed in expensive equipment, ascertaining problems becomes difficult if the equipment is set up in an unexposed space. The control box is only opened during scheduled maintenance or when anomalies occur. Therefore, in this paper, a method is proposed for facilitating the safety management and maintenance of equipment when necessary, instead of waiting for anomalies or scheduled maintenance. A Bluetooth 4.0 low-energy current-sensor system based on near-field communication is used, which compensates for the nonlinearity of the current-sensor output signal using a piecewise linear model. The sensor is controlled using its generic attribute profile. Sensor nodes and cell phones used to check the signals obtained from the sensor at 50-A input currents showed an accuracy of ±1%, exhibiting linearity in all communications within the range of 0 to 50 A, with a stable output voltage for each communication segment.

Deformation Technology for Thick Plate Using Single Pass Line Heating by High Frequency Induction Heating (고주파 유도 단일패스 선상가열 유기 후판 성형 기술)

  • Lee, K.S.;Eom, D.H.;Kim, C.W.;Pyun, S.Y.;Son, D.H.;Gong, G.Y.;Kim, B.M.;Lee, J.H.
    • Transactions of Materials Processing
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    • v.20 no.6
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    • pp.439-449
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    • 2011
  • The temperature distribution and subsequent permanent deformation of SS400 carbon steel plate subjected to an induction-based line heating process were studied by a numerical method involving coupled 3-D electromagnetic-thermal-structural analysis. The numerical study revealed that the amount of permanent deformation is strongly related to the Joule loss caused by such process conditions as input power and moving speed of the heat source. To validate the numerical analysis results, line heating experiments were carried out with a high frequency(HF) induction heating(IH) equipment capable of bending thick plate with the moving accuracy of ${\pm}0.1mm$ in heating coil position. The amount of permanent deformation increased with decreasing moving speed and increasing input power.

Analysis of Over-current Characteristics in YBCO Coated Conductor (YBCO Coated Conductor의 과전류 특성해석)

  • Lee, C.;Nam, K.;Kang, H.;Ko, T.K.;Seok, B.Y.
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.693-694
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    • 2006
  • In order to develop a high temperature superconducting(HTS) coil for the fault current limiter(FCL), the over-current characteristics in YBCO coated conductor(CC) with Ni-W alloy substrate are analyzed. The HTS wire is wound by bifilar winding method for resistive current limitation and it is operated in 65K sub-cooled nitrogen. In order to analyze the resistance and the temperature characteristics of the CC wire, an analysis program is developed considering all the composition materials except the buffer layer. Using this program, the temperature rise, the resistance development and the current limitation of CC are calculated depending on the applied voltage and the stabilizer materials. According to the analysis results, under the temperature restriction of 300K, the maximum voltage per meter is determined as 40V/m if the stabilizer is $25{\mu}m$ thick stainless steel at each side. Finally, the wire length needed for the distribution level HTS FCL is estimated.

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Development of Somaloy Components for a BLDC Motor in a Scroll Compressor Application

  • Persson, Mats;Nord, Goran;Pennander, Lars-Olov;Atkinson, Glynn;Jack, Alan
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.804-805
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    • 2006
  • Electric scroll-compressor drives are commonly used for e.g. home appliance cooling units. The recent development of hybrid cars with internal combustion engine in combination with electrical propulsion requires new solutions to be able to cool the passenger compartment of cars at stand-still. Both application areas demand efficient motor drives to reach good economy and efficient use of limited battery power as well as competitive volume/weight for a given output. The BLDC motor is a controllable and efficient solution. A major part of the motor is the soft-magnetic core. The powder based $Somaloy^{(R)}$ material shows high resistivity and induction as the result of engineered iron particles with in-organic coating. The unique features of compacted $Somaloy^{(R)}$ components can be utilized to enhance the shape and total volume of the BLDC motor with at least maintained efficiency compared to the use of traditional laminated steel sheet cores. A careful design of the $Somaloy^{(R)}$ components can also simplify assembly and positively influence the coil configuration. This study shows a comparison between a typical laminated BLDC motor and a redesigned, $Somaloy^{(R)}$ based version adapted for a scroll-compressor application.

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An Experimental Study on the heat transfer characteristics and performance of storage tanks with mantle heat exchanger (맨틀형 축열조의 열전달 성능 및 특성에 관한 실험적 연구)

  • Kang, Y.H.;Kwak, H.Y.;Yoon, H.G.;Yoo, C.G.;Yoon, H.S.;Chun, W.G.
    • Journal of the Korean Solar Energy Society
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    • v.21 no.1
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    • pp.61-69
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    • 2001
  • The heat transfer characteristics of horizontal and vertical mantle heat storage tanks are studied in order to replace the tank-coil heat exchanger for application in thermosyphon solar water heaters. In this study, 5 mantle storage tanks with different geometric shape are manufactured into stainless steel and each tank is tested. For the test, The inlet flow rate of the heat transfer fluid is maintained 1.2 lpm consistently. The heat transfer fluid temperature through the mantle is $70{\pm}1^{\circ}C$. The temperatures of 26 points included the ambient temperature are measured at every one minute. The measured data are used to calculate the overall heat transfer coefficient(UA) using the LMTD(Log Mean Temperature Difference) method and it is used on the analysis of the heat transfer characteristics to search for optimum arrangement.

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A Study on the Application for the Vibration Active Control by using a Voice call type LOA (보이스코일형 LOA의 진동능동제어 시스템에의 응용에 관한 연구)

  • Jang, S.M.;Jeong, S.S.;Seo, J.H.;Kim, H.G.;Park, H.C.;Moon, S.J.;Chung, J.A.;Park, C.I.;Chung, T.Y.
    • Proceedings of the KIEE Conference
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    • 1996.11a
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    • pp.317-319
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    • 1996
  • In this paper, an active vibration control system using a voice coil type linear oscillating actuator(LOA) is studied to suppress structural vibration. Being compared with a hydraulic actuator, a LOA has simplified structure and requires a few elements in the driving system, so it has lots of merits with respect to economics and maintenance. The general mathematical dynamic model to obtain the algorithm for the realization of vibration active control system is treated. Actually, the performance test of the control system using LOA is carried out on a steel test structure under sinusoidal and white noise excitation. From this test it is conformed that acceleration level of test structure is reduced near the resonance region. In the future research on the application to large structures will be studied.

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Development of the KSTAR Superconductor

  • Lim B.S.;Choi J.Y.;Lee S.I.;Kim D.J.;Park W.W.;Woo I.S.;Song Y.J.;Song N.H.;Kim C.S.;Lee D.G.;Kim K.P.;Park H.T.;Joo J.J.
    • Progress in Superconductivity and Cryogenics
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    • v.8 no.2
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    • pp.25-28
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    • 2006
  • The magnet system of KSTAR(korean Superconducting Tokamak Advanced Research) is consisted of 16 TF (Toroidal Field) coils and 14 PF (Poroidal Field) coils. Internal cooling CICC(Cable in Conduit Conductor) type conductor is used for both of TF and PF coil systems. The conduit material for $Nb_3Sn$ cable is Incoloy 908 and 316LN stainless-steel was used as conduit material for NbTi cable. $Nb_3Sn$ CICC is used for all TF coils and PF1-5 coils while NbTi CICC is used for PF6 and 7 coils. $Nb_3Sn$ and NbTi strands were made for KSTAR superconducting strand. They are satisfied with KSTAR superconducotr requirements. The $Nb_3Sn$ strands supplied from three companies; MELCO (Mitsubishi Electric Co.), OAS (Outokumpu Advanced Superconductor) and KAT (Kiswire Advanced Technology) were used. A special CICC jacketing system is developed for the KSTAR CICC fabrication which uses the tube-mill process consisted of forming, welding, sizing and squaring procedures. The. procedures for cabling and jacketing of CICC for TF and PF coils and their results including the geometrical specification and characteristics of strands are described.

A computer Hardware Selection Strategy for Information Systems Development : A Case of T Coil Service Center (정보시스템 구축시 컴퓨터 하드웨어의 선정전략 - T 철강회사의 시스템 선정 사례 -)

  • Yu, Sang-Jin;Jang, Yeong-Taek
    • Asia pacific journal of information systems
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    • v.3 no.2
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    • pp.3-54
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    • 1993
  • Recently, executives learned of the strategic impact that information systems (IS) and information technology (IT) could provide to their organizations. In other words, through IS/IT companies could squelch competition, secure suppliers, obtain customer loyalty, reduce the threat of new entrants, and identify new opportunities. Because of these potential benefits, organizations are investing ever-increasing amount of organizational resources in IS/IT to make their organizations as information-based ones. Information-based organizations depend largely upon computer hardwares and softwares for their ongoing operations and management. Thus, organizations must manage their information resources, especially hardwares and softwares very effectively to remain competitive. Information resource management (IRI) is a program of activities directed at making effective use of information technology within an organization. These activities cover from corporate IS/IT planning to application system development, implementation, and maintenance. In more detail, IRV activities include planning for and acquiring computer hardwares and communication equipments, planning for, selection, and management of software development projects, and re-engineering business processes as IS/IT are integrated into organizational management. Among these activities, planning for and acquisition of computer hardwares, and planning for and management of software projects are the most critical ones since these activities require enormous amount of such important corporate resources as money, people, and time. Furthermore, corporate's eventual success largely depends upon whether corporate's policy on IS/IT is effective one or not. Numerous approaches and concepts to specific IRM activities have been proposed. However, many organizations have experienced various problems in the process of applying these approaches to their IRM activities mainly because existing methodologies and guidelines are too general to adapt to each firm's unigue situation. Also, these approaches are having its own strengths and weaknesses. Thus, people in charge of organization's IRM policy should come up with effective guidelines to maintain his position very long. In this study, we reviewed some existing approaches for planning, evaluation, and acquisition of computer hardware. Then, real experiences from Taechang Steel Co., Ltd. located in Taegu, which is one of the largest Coil Service Centers in Korea, are discussed. The major purposes of the study are : (1) to discuss the tradeoffs of existing approaches on hardware evaluation and acquisition, (2) to provide a real experience of a company to facilitate the application of theoretical concepts to the real environment.

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Development of Liquid Density Measurement Sensor Using the Natural Frequency of a Pipe (파이프의 고유진동수를 이용한 액체밀도측정 센서개발)

  • Chang, Kyung-Ho;Lee, Yong-Jae;Kim, Kwang-Pyo;Ahn, Byung-Duk
    • Journal of Sensor Science and Technology
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    • v.4 no.3
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    • pp.9-14
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    • 1995
  • For the development of liquid density measuring sensor using the natural frequency of a pipe, its principle and construction method were described. The stainless steel pipe, which has length of 32 cm, inside diameter of 2.3 cm and outside diameter of 2.5 cm, was used for the sensor. The exciting coil and the photo sensor were used to excite and to pick-up it, and the feedback circuit was designed to continue its vibrating. The natural frequency was consistent with the result of the spectrum analysis. It had a linearity of 0.0027 % and a sensitivity of 0.032 % in liquid density range from $0.8\;g/cm^{3}$ to $1.4\;g/cm^{3}$ and its frequency variation ratio was 0.024 $%/^{\circ}C$ in temperature range from $10^{\circ}C$ to $35^{\circ}C$.

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