his paper is concerned with quantitative evaluation of corrosion shape on outer surface of Pipe by Electro agnetic Acoust ic Transducer (EMAT). The pipe wall thinning was modeled semi ellipse shape. And FAC s been considered more dangerous. Th e pipe wall thinning was able to be measured with precision. In neral, FAC had a smooth surface wall thinning. EMAT were a ble to measure the echo in the test piece with 11 thinning of smooth enough. The EMAT is able to use to test for the FAC....
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Measurement method of Pipe Wall Thinning Shape by EMAT

This paper aims at a detecting corrosion on the back surface of a ick steel plate. Our proposed technique is characterized by using pulsed eddy current testing with DC magnetization. The thick steel plate is magnetized by DC Magnetizer. Therefore the magnetization g erates the magnetic flux in the plate. The permeability of the plat e changes with the corrosion. Changes in the permeability of the pl ate are detected by pulsed eddy current testing. The corrosion on e back surface of the plate was detecte...
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Corrosion Detection on Steel by using Pulsed Eddy Current Testing

This paper is concerned with a simulator related to nondestructive test using Electromagnetic Acoustic Transducer (EMAT). The simulator developed here can be applied to pipe wall thinning of stainless steel used in nuclear power plants. First, mathematical models for the inspection are given by a transient e ddy current equation and by a time dependent elastic wave equation in two dimensions. Secondly, shape of pipe wall thinning is modeled by B-spline functio n and is applied to the mathematical models us...
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Development of NDT Simulator with Method of Mapping for Detection of Pipe Wall Thinningusing EMAT

This paper is motivated by the desire to evaluate thickness of zinc layer on steel in a manufacturing process of zinc plating. A short distance between a blower for blowing liquid zinc and a sensor for measuring thickness of the layer, and a long distance between the sensor and test samples are required in the process. We have tried to apply the eddy current testing for measuring thickness of a zinc layer with vibration. This paper shows the calculated phase dependencies of an eddy current sensor on the th...
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Measurement of Plating Thickness with Vibration by Eddy Current

In a nuclear power plant, when external stresses such as huge earthquake are added, residual strain may have occurred in the structure. In this researc h, SUS316L and SS400 which applied the stress and added residual strain, are created, and the possibility of diagnosing of the residual strain nondestr uctively from the magnetic characteristic of test pieces are examined. The basic magnetic characteristics were measured by a coil wound up the specimen directly, and the nondestructive measurements were carr...
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Magnetic Characteristic of Strain Metal Materials

This paper is concerned with quantitative evaluation of pipe wall thickness Electro Magnetic Acoustic Transducer (EMAT). This pipe wall thinning occurs on a piping internal wide range at an orifice, an elbow, and a reducer downstream. A shape of a pipe wall thinning like Flow-Accelerated Corrosion (FAC) is near arc. And a pipe wall thinning has the s urface like scales. Test samples were fabricated to simulate FAC in the series of experiments. A shape of corrosion of the test samples is arc. Other test sam...
英字タイトル:
Measurement of Pipe Wall Thickness using EMAT in Flow-Accelerated Corrosion

This paper aims at detecting thinning of the back surface of a steel double sided structure. Our proposed technique is characterized by using pulsed eddy current testing with DC magnetization. When a double structural steel is magnetized by DC current, flux leakage is generated as a result of thinning on the back surface. We have shown by the use of simulations that the permeability of the top plate has changed with flux leakage from the back plate. The steel plate without thinning and the steel plate...
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Detecting Thinning on Back Surface of Double Structure of Steel by Pulsed Eddy Current Testing with DC magnetization

This paper is concerned with quantitative evaluation of pipe wall thickness using Electro-Magnetic Acoustic Transducer. Various test specimens are fabricated to simulate Flow-Accelerated Corrosion (FAC). First, measurements by Electro-Magnetic Resonance (EMAR) technique are examined. It is found that the resolution of thickness measurements is superior to the Pulse-Echo method. On the other hand, the measurement by EMAR is time-consuming because it requires long range of sweeping frequencies. Secondl...
英字タイトル:
Measurement of Pipe Wall Thickness using Electro Magnetic Acoustic Transducer

This paper is concerned with signal processing arising in pipe wall thinning measurements using electromagnetic acoustic transducer (EMAT). First, electromagnetic acoustic resonance method (EMAR) is applied to pipe wall thickness measurement. Secondly, a heuristic method for extracting features of resonance spectrum obtained by testing data is proposed. Finally , the validity and the feasibility of our proposed method are demonstrated through the practical test at the real plant....
英字タイトル:
Signal Processing for Pipe Wall Thickness Measurements using Electromagnetic Acoustic Resonance Method

This paper is concerned with quantitative evaluation of corrosion shape on back surface of Stainless s amples by Electro Magnetic Acoustic Transducer (EMAT). First we summarize numerical studies of the qua ntitative nondestructive evaluation by EMAT. Secondly, a method for recovering corrosion shape is prop osed. Aspect ratio (corrosion height / corrosion radius) is important for recovery a corrosion shape....
英字タイトル:
Identification of Corrosion Shape by EMAT