Visualization and Quantitative Research of Stress Corrosion Cracking Using the Three-Dimensional Phased Array Ultrasonic Technique
北澤 聡 So KITAZAWA 河野 尚幸 Naoyuki KONO 工藤 健 Takeshi KUDO 井坂 克己 Katsumi ISAKA
Phased Array Stress Corrosion Cracking (SCC) Three-Dimensional Ultrasonic Testing
The three-dimensional phased-array (3D-PA) ultrasonic technique has been applied to a stress corrosion cracking (SCC) in base metal, and its results for sizing have been quantitatively evaluated. The 3D-PA allows operators to scan objects volumetrically and to display results as 3D images facilitating evaluation processes considerably. The scanning pattern used is called the moving rotational sectorial-scan (MRS-scan) and it is composed of many sectors of different azimuth angles as moving the probe linearly. The MRS-scan significantly improves the inspection of flaws without skillful searching motion of the probe, because the flaws are stereoscopically insonified by a number of ultrasonic beams coming from various directions. The SCC was evaluated by the MRS-scan with a matrix array probe. Not only the deepest tip but also all parts of the crack were able to be successfully visualized and sized with an accuracy of the root mean square error of 0.9 mm.