What are the main parameters of ultrasonic flaw detector?

 

Main parameters of ultrasonic flaw detector

 

Sensitivity

 

In ultrasonic testing, sensitivity generally refers to the ability of the entire testing system (instrument and probe) to detect the smallest defect. The smaller the defect, the higher the sensitivity.

 

The sensitivity of the instrument's probe is often measured by the sensitivity margin. The sensitivity margin refers to the total amount of attenuation required to make the echo of a specified reflector reach the reference height when the instrument is at its maximum output (gain and emission intensity are maximum, attenuation and suppression are 0). A large sensitivity margin indicates that the sensitivity of the instrument and probe is high. The sensitivity margin is related to the comprehensive performance of the instrument and probe, so it is also called the comprehensive sensitivity of the instrument and probe.

 

Blind zone and initial pulse width

 

The blind zone refers to the minimum distance from the detection surface to where defects can be found. Defects within the blind zone cannot be found at all.

 

The initial pulse width refers to the length of the initial pulse when the height on the screen exceeds 20% of the vertical amplitude under a certain sensitivity. The initial pulse width is related to the sensitivity. The higher the sensitivity, the larger the initial pulse width.

 

Resolution

 

The resolution of the instrument and probe refers to the ability to distinguish two adjacent defects on the screen. The smaller the distance between two adjacent defects that can be distinguished, the higher the resolution.

 

Signal-to-Noise Ratio

 

The signal-to-noise ratio refers to the ratio of the amplitude of the useful minimum defect signal on the screen to the amplitude of the useless noise and clutter. A high signal-to-noise ratio means less clutter, which is beneficial for flaw detection. A low signal-to-noise ratio can easily lead to missed detection or misjudgment, and in severe cases, even make flaw detection impossible.