What Is an Ultrasonic Probe?

An ultrasonic probe is a device that transmits and receives ultrasonic waves during the ultrasonic detection process. The performance of the probe directly affects the characteristics of the ultrasound and affects the detection performance of the ultrasound.

Ultrasonic probe

The probe used in ultrasonic testing is a transducer that uses the piezoelectric effect of the material to convert electrical energy and sound energy. The key component in the probe is the wafer. The wafer is a single-crystal or poly-crystalline sheet with a piezoelectric effect. Its function is to convert electrical and acoustic energy into each other.

Chinese name: Ultrasonic probe
Foreign name: Ultrasonic probe

Straight probe: Single crystal longitudinal wave straight probeDual crystal longitudinal wave straight probe
Oblique probe: Single crystal

1.Straight probe: Single crystal longitudinal wave straight probeDual crystal longitudinal wave straight probe

2.Oblique probe: single crystal

1. Piezoelectric strain constant d33:

d33 = Dt / U When a large stress of U is applied to the piezoelectric wafer, the thickness of the piezoelectric wafer changes by Dt. The larger d33, the higher the emission sensitivity.

2. Piezoelectric voltage constant g33:

g33 = UP / P puts such a large stress on the piezoelectric chip. When a voltage as large as UP is generated on the piezoelectric chip, the larger the g33, the higher the receiving sensitivity.

3. Dielectric constant e:

e = Ct / A [C-capacitance, t-plate distance (wafer thickness), A-plate area (wafer area)];

C small e small short charge and discharge time. High frequency.

4. Electromechanical coupling coefficient K:

Represents the mechanical energy of piezoelectric materials (

(Attentions)

1. Shear wave probes only report K values, not frequency and chip size.

2. Dual-crystal probe only reports frequency and chip size, not F (diamond-shaped area)

Oblique probe

Emphasize the role of equivalent test blocks.

1. There are problems with the structure and dimensions of common test blocks and the use of various parts; (Answers to questions 8, 10, 13, 18 of the lecture attachment).

2. 2. The difference between triangular groove and wire cutting crack; Comparison of defects in vertical holes and workpieces:

4 How to use several homemade test blocks;

A. Austenitic test block:

B. Two-hole calibration (mainly used for P-wave oblique probe inspection, such as bolts) (Answers to Questions 5 and 7 of the lecture notes)

Calculation formula: let h2 / h1 = n;

a = [n (t1 + f / 2)-(t2 + f / 2)] / (n-1) Formula 1

t1 and t2 are one

Curve method

2.Amplitude method.