Two magnetic methods are proposed for the evaluation of initial degradations of type 304 stainless steel in stress corrosion cracking (SCC). The first one is the measurement of the distribution of chromium depletion by means of a magnetic force microscope (MEM). MEM observations are performed for some samples sensitized in various conditions, and the obtained results coincide with the expected ones from the chromium behavior. Moreover, the phase distributions in the solution-annealed and sensitized states a...
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Evaluation of Initial Degradation in Stress Corrosion Cracking by Magnetic Methods

Evaluation of defect and damage for structural materials of energy device was performed by using ectromagnetic techniques. For degradation of thermal aging magnetic characterization of weld specimens HCM12A was performed. Comparing the specimen aged at 550°C for 2000 hours with that aged at D0°C for 600 hours, it was found that the changes in magnetic flux densities was clearly observed near the eld metal and heat affected zone for the specimen aged at 550°C for 2000 hours. Then the degree of egradation fo...
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Evaluation of Defect and Damage for Structural Materials of Energy Device by Using Electromagnetic Techniques

Using Hall and ECT sensors, a non-destructive damage evaluation was performed for the specimen of rail eel with simulated white damage layers. Two types of specimens were used, one with a simulate d white amage layer of 1mm depth and the other that of 100um. First using Hall sensor, distributio n of magnetic ux around the white damage layers was measured by means of magnetic flux leakage tec hnique. Both agnetic flux leakages of B, and B, revealed the presence of the white damage layers. Also from the ag...
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Non-destructive Damage Evaluation of Rail Steel Using Electro-magnetic Techniques

Defect in a stud bolt was evaluated by using fluxgate (FG) magnetic sensor. In order to analyze defect shape and size quantitatively, the relationship between magnetic flux densities and magnetic dipole moment on the defect plane was formulated in cylindrical coordinate system. Periodicity was observed alonglongitudinal direction in magnetic flux density distribution measured by fluxgate magnetic sensor. The inverse analysis based on Tikhonov regularization technique was performed by using magnetic flu...
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Evaluation of Surface Defect on ComplexShapedComponentBased on Electromagnetic Inverse Analysis

The technique of obtaining shape of inclined defect at heat affected zon e for welded specimen of high chromium steel was proposed. In this techn ique, magnetic flux leakage measurement and the inverse analysis using s ingular value decomposition were used. Suitable defect shape was obtained from the magnetic flux density distribution under the high magnetic fiel d without being subject to the influence of a welding part. Under the lo w magnetic field, suitable defect shape was obtained by subtracting the ...
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Proposal of electromagnetic inverse analysis technique about the inclineddefect for welded specimen of high chromium steel

Carbon fiber-reinforced plastics (CFRP), which is expected to reduce the weight or increase the efficiency of transportations and energy products, was cut by an CO2 gas laser (10.6um, 800W, 20kHz, 8us, 1m/min), CW single-m ode fiber laser (1.07um, 300W, 2000W, CW single-mode, 1m/min, 7m/min) and machining with milling. Although the high-power laser cutting processes make it possible to improve cutting rate of CFRP, the laser-cut specimens cl early showed a thermal damage with a heat-affected zone (HAZ) ide...
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(CFRP) using High-power Laser Cutting ProcessStudent Member