Ultrasonic Thickness Testing to check flaws inside materials

July 29, 2025

A-scan and B-scan functions can give detailed information about internal structure of material, complementing thickness testing.

A-scan and B-scan are two common display modes used in ultrasonic thickness testing, each providing different types of information about the material being tested.

A-scan (Amplitude Scan):

This mode displays a one-dimensional representation of the ultrasonic signal. It shows the amplitude of the received echoes as a function of time.
The horizontal axis represents time (or depth), while the vertical axis represents the amplitude of the reflected signals.
A-scan is useful for determining the thickness of a material by measuring the time it takes for the ultrasonic pulse to travel to the back wall and return.
It provides precise measurements and is often used for detecting flaws or discontinuities within the material. Once the thickness is known, any pulse received before the backwall can be used to inspect further for flaws and discontinuities.

B-scan (Brightness Scan):

B-scan provides a two-dimensional cross-sectional view of the material. It combines multiple A-scans taken at different positions to create a visual representation.
The horizontal axis typically represents the position along the test surface, while the vertical axis represents depth. The brightness of the display indicates the amplitude of the reflected signals.
B-scan is particularly useful for visualizing the internal structure of a material, allowing for the identification of flaws, corrosion, or other anomalies over a larger area.

There are various factors like Gain, Frequency, time base, damping, etc to fine-tune the testing to get accurate results. Both A-scan and B-scan are essential tools in ultrasonic testing, providing valuable insights into material integrity and thickness.

Our Ultrasonic Thickness Tester Metrix+ UTM 90CT and Ultrasonic Flaw Detector Metrix+ UTFD 80 can help in flaw detection of materials.