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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Nondestructive Testing
Journal Basic Information
Journal DOI :
The Korean Society for Nondestructive Testing
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Volume & Issues
Volume 28, Issue 6 - Dec 2008
Volume 28, Issue 5 - Oct 2008
Volume 28, Issue 4 - Aug 2008
Volume 28, Issue 3 - Jun 2008
Volume 28, Issue 2 - Apr 2008
Volume 28, Issue 1 - Feb 2008
Selecting the target year
Inductive Micro Thin Film Sensor for Metallic Surface Crack Detection
Kim, Ki-Hyeon ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 395~400
Alternating magnetic field was used for detection of surface flaws on nonmagnetic and magnetic metallic specimens. The nondestructive sensor probe was composed of the planar coil with inductive magnetic thin film yoke as a sensing component and a single straight typed exciting coil. The planar inductive coil sensor with magnetic yoke was fabricated by sputtering, electroplating, dry etching and photolithography process. The alternative currents with the range of 0.1A to 1.0A (0.7 MHz to 1.8 MHz) were applied to the exciting coil. The specimens were prepared with the slit shaped artificial surface flaws (minimum depth and width; 0.5 mm) on metallic plate (Al; nonmagnetic metal and FeC; magnetic metal). The detected signal for the positions and shapes of surface flaws on specimens were obtained with high sensitivity and high signal to ratio. The measured output signals by the non-contacted scanning on surface of FeC specimen with micron-sized crack were converted to the images of the flaws. And these results were compared with the optical images, respectively.
Development of Magnetoimpedance Sensor Utilizing Soft Magnetic Amorphous Ribbon with Exchange Coupling and Application to Nondestructive Testing
Yoon, Seok-Soo ; Kim, Gun-Woo ; Lee, Sang-Hun ; Kim, Cheol-Gi ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 401~406
Recently, portable magnetic sensors with high sensitivity are strongly required for various applications such as biosensor, nondestructive testing and directional sensor. A novel magnetic sensor system was developed by utilizing giant magnetoimpedance(MI) effect of soft magnetic ribbons. The sensor system consists of sensing head of
ribbon having asymmetric MI characteristics through exchange coupling produced by field-annealing in open air and circuit for signal processing. The sensor system showed almost linear characteristics in dynamic range of
and sensitivity of 10.5 V/Oe. The sensor was applicable to nondestructive testing system to detect defects in wire ropes.
Nondestructive Examination of Ferromagnetic Tube Using Magnetic Saturation Eddy Current Technique
Lee, Hee-Jong ; Cho, Chan-Hee ; Song, Seok-Yoon ; Jee, Dong-Hyun ; Jung, Jee-Hong ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 407~415
The tubes in heat exchanger are typically made from copper alloy, stainless steel, carbon steel, titanium alloy material. type-439 ferritic stainless steel is ferromagnetic material, and furnish higher heat transfer rates than austenitic stainless steels and higher resistance to corrosion-induced flaws. Ferritic stainless steel can typically be found in low-pressure(LP) feedwater heaters and moisture separator reheaters(MSRs). LP feedwater heaters generally utilize thin wall type-439 stainless steel tubing, whereas MSRs typically employ a heavier wall tubing with integral fins. Service-induced damage can occur on the OD(outside diameter) surface of type-439 ferritic stainless steel tubing which is employed for MSRs tubing, and the most typical damage mechanism is vibration-induced tube-to-TSP(tube support plate) wear and fatigue cracking. The wear has been reported that occurs mainly on the OD surface. Accordingly, in this study, we have evaluated the flaw sizing capability of magnetic saturation eddy current technique using magnetic saturation probe and flawed specimen.
Spiral Coil Magnetostrictive Strip Transducers for Long Range Ultrasonic Testing of Cylindrical Structures
Heo, Won-Nyoung ; Choi, Myoung-Seon ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 416~420
In EMAT field, spiral RF coils are much more widely used when compared with solenoid coils. In the field of the magnetostrictive strip transducers for long range ultrasonic testing of cylindrical structures, however, solenoid coils has been used. This seems to be attributed to the difficulty in fabricating low frequency (i.e., large size) spiral coils. In this paper, we describe a method for fabricating spiral coil magnetostrictive strip guided wave transducers from FFC (flexible flat cable). It is demonstrated through a comparison experiment that the spiral coil transducer has much superior performance (sensitivity, SNR, and guided wave direction control capability) than the previous transducer with solenoid coils.
Magnetic Bio-Sensor Using Planar Hall Effect
Oh, Sun-Jong ; Hung, Tran Quang ; Kumar., S. Ananda ; Kim, Cheol-Gi ; Kim, Dong-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 421~426
The magnetic bio-sensor used the PHR (planar hall resistance) effect generated by the free layer in spin-valve giant magnetoresistance structure of Ta/NiFe/CoFe/Cu/NiFe/IrMn/Ta. The PHR element with micrometer size was fabricated through the photolithograph and dry etching process. The PHR signal with magnetic field was measured under the conditions of with and without single magnetic bead. A single magnetic bead of diameter
was successfully detected using the PHR sensor. Therefore, the high resolution PHR sensor can be applied to bio-sensor application utilizing the output voltage variation of the PHR signals in the presence and absence of a single magnetic bead.
Determination of Focal Laws for Ultrasonic Phased Array Testing of Dissimilar Metal Welds
Jing, Ye ; Kim, Hak-Joon ; Song, Sung-Jin ; Song, Myung-Ho ; Kang, Suk-Chull ; Kang, Sung-Sik ; Kim, Kyung-Cho ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 427~435
Inspection of dissimilar metal welds using phased array ultrasound is not easy at all, because crystalline structure of dissimilar metal welds cause deviation and splitting of the ultrasonic beams. Thus, in order to have focusing and/or steering phased array beams in dissimilar metal welds, proper time delays should be determined by ray tracing. In this paper, we proposed an effective approach to solve this difficult problem. Specifically, we modify the Oglivy's model parameters to describe the crystalline structure of real dissimilar metal welds in a fabricated specimen. And then, we calculate the proper time delay and incident angle of linear phased array transducer in the anisotropic and inhomogeneous material for focusing and/or steering phased array ultrasonic beams on the desired position.
Feasibility of Ultrasonic Inspection for Nuclear Grade Graphite
Park, Jae-Seok ; Yoon, Byung-Sik ; Jang, Chang-Heui ; Lee, Jong-Po ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 436~442
Graphite material has been recognized as a very competitive candidate for reflector, moderator, and structural material for very high temperature reactor (VHTR). Since VHTR is operated up to
, small amount of impurity may accelerate the oxidation and degradation of carbon graphite, which results in increased porosity and lowered fracture toughness. In this study, ultrasonic wave propagation properties were investigated for both as-received and degradated material, and the feasibility of ultrasonic testing (UT) was estimated based on the result of ultrasonic property measurements. The ultrasonic properties of carbon graphite were half, more than 5 times, and 1/3 for velocity, attenuation, and signal-to-noise (S/N) ratio respectively. Degradation reduces the ultrasonic velocity slightly by 100 m/s, however the attenuation is about 2 times of as-receive state. The results of probability of detection (POD) estimation based on S/N ratio for side-drilled-hole (SDHs) of which depths were less than 100 mm were merely affected by oxidation and degradation. This result suggests that UT would be reliable method for nondestructive testing of carbon graphite material of which thickness is not over 100 mm. In accordance with the result produced by commercial automated ultrasonic testing (AUT) system, human error of ultrasonic testing is barely expected for the material of which thickness is not over 80 mm.
Magnetoresistance Effect and Sensor Applications
Kim, Dong-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 28, issue 5, 2008, Pages 443~449