Eddy Current Testing signals of the transmission/receiver (TR) type probe can be influenced by the directivity of the probe. In the previous study, ECT signal change due to scanning angle was evaluated in ferromagnetic material using a TR type probe, but the mechanism of the change is still not clear. In this study, ECT is conducted changing the orientation of the TR probe both on carbon steel and on austenitic stainless steel, to investigate the mechanism. The results show that the directivity of the probe...

This paper evaluated the probability of detection(POD) of austenitic stainless steel welds from the viewpoint of ultrasonic testing. It presents results of simulation-based POD curves of ultrasonic NDT. The simulation model based on a three-dimensional Finite Element Method (FEM) is presented to perform the data generation. Results of conventional POD considering the depth of flaw are given and the requirement of taking the length of flaw into considered is determined....
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Probability of detection analysis of ultrasonic NDT applied to austenitic stainless steel welds

Abstract: In nuclear power plants (NPPs), due to flow accelerated corrosion (FAC) and liquid droplet impingement (LDI) of the coolant inside the pipe, there may happen local wall thinning defects on the inner surface of a pipe. Concerning the material of pipes, there are mainly two types, low-carbon steel and stainless steel. In this paper, the feas ibility of quantitative nondestructive evaluation (QNDE) to wall thinning in stainless steel pipes using pulsed eddy current testing (PECT) method is discussed...
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Quantitative NDE of pipe wall thinning using pulsed eddy current testing method

The authors have proposed a novel probe combining angle beam EMAT (Electro magnetic Acoustic Transducer) and EC (Eddy Current) Probe as a multi-probe with simple structure. In this paper, the structure of the above dual pro be is improved in order to increase sensitivity of the probe as EC probe....
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Proposal of EMAT-EC Dual Probe for Monitoring of Crack Propagation

We are developing remote filed eddy current testing (RFECT) method using pancake coils for evaluating local wall thinn ing of large diameter pipes. This paper shows a study to improve the detectability and sizing capability of this RFECT method. The study was performed by numerical calculations and laboratory experiments. The results show that introduci ng differential pick-up coils makes detection signals more stable and improves the detectability of our RFECT method....
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Improvement of remote field eddy current testing using pancake coils

This paper studies a method of non-destructive evaluation for the hardness of ductile cast irons employing an AC magnetization probe that evaluates the differences in magnetization characteristics. The analysis of the waveform obtain ed from the probe on the ductile cast iron specimens performs estimating their hardness since mechanical properties are strongly related to two factors: the graphite shape matrices mainly composed of pearlite and ferrite. The wavefor ms around Rayleigh region yield the essenti...
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Foundry Material Property Evaluation Employing AC Magnetization Probe

This study proposes a novel nondestructive evaluation method of chill contents in gray cast irons by means of AC magnetization method. For the purpose, magnetic properties of cast irons w ith different chill contents were evaluated by B-H loop analyzer. Results were discussed in view of matrices and graphite, and it was found that some magnetic parameters, especially B-H l oop area, correlate well with ratio of cementite area to graphite one. Focusing on the fact, AC magnetic method was applied to evaluati...
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Evaluation of Chill Contents in Flaky Cast Irons Based on AC Magnetization Method

It is difficult to predict an initiation and growth of ageing/degradation like SCC in plant comp onents, subsequent component failures, function losses or a behavior of gigantic, complex plant system like a nuclear power plant. But if it is possible to predict them, it could drastically improve the safety and economic efficiency of such plant systems. This study considered a struc ture and system of maintenance since that could improve a predictive performance of maintenance related science and engineerin...
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Study of How to Confirm the Completeness of Maintenance Activity Planby Using Maintenance Scientific Imagination

This paper shows phase characteristics of crack indications obtained with a multi-coil ECT probe, and proposes a method to reduce noise and extract crack indications from the detection signals of this multi-coil ECT p robe based on these phase characteristics. Because this multi-coil ECT probe performs two kinds of scanning patterns: U-scan and T-scan, and obtains two sets of signal distributions for one scanning area simultaneousl y, the proposed method uses a two-stage process that includes so-called a m...
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Extraction of crack indications from ECT signals by using signal phase characteristics

The authors have proposed a novel eddy current testing(ECT) probe for thick-walled plates. A basic concept of the probe is that a couple of differential pick-up coils is arranged between two exciting coils carrying currents opposite to each other. This arrangement allows strong eddy currents opposite to scan surfaces and the weak decay of eddy currents in the thickness direction. In this study, the present probe was applied to ECT of welding area. For the purpose, experiments were carried out u...
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Weld Inspection Using Eddy Current Testing Probe for Thick-walled Plates