| 摘要 |
PURPOSE:To enable flaw detection of a ferrite-austenite two-phase stainless steel and austenitic stainless steel by setting the incident direction of ultrasonic waves having 2.5-4.5MHz flaw detection frequency and 40-50 angle of refraction at 0-15 deg. or 75-90 deg. direction with the rolling direction of a material. CONSTITUTION:The reason for limiting the flaw detection frequency of a probe lies in that sufficiently high S/N is obtainable in this range with the ferrite- austenite two-phase stainless steel and austenitic stainless steel. While the S/N is smaller with the two-phase stainless steel than with carbon steel, the sufficiently high S/N is obtainable in the 2.5-4.5MHz range. The reason for limiting the angle of refraction of the probe at 40-50 deg. lies in that the high S/N is obtainable at the angle of refraction within this range. |
