1. Clarify the detection sensitivity of ultrasonic flaw detector
It is not good if the sensitivity of the ultrasonic flaw detector is too high or too low. If the sensitivity is too high, there will be too much clutter, making it difficult to judge the damage. If the sensitivity is too low, it will cause missed detection. Therefore, before ultrasonic flaw detection, a specific artificial reflector on the test block is often used to adjust the sensitivity of the ultrasonic flaw detector.
2. Test the application function of ultrasonic probe
Some important functions of ultrasonic flaw detectors and probes, such as expansion linearity, horizontal linearity, dynamic range, sensitivity margin, resolution, blind zone, probe incident point, K value, etc., are tested using test blocks.
3. Adjust the speed of ultrasound scanning
The use of ultrasonic flaw detector test blocks can adjust the proportional relationship between the horizontal scale value on the instrument screen and the actual sound path, that is, the scanning speed, in order to locate defects.
4. Determination of defect size
Using the distance-amplitude-equivalent curve drawn by some ultrasonic flaw detector test blocks (that is, applicable to AVG) to quantify defects is one of the currently commonly used quantitative methods. Especially for defects within 3N, the test block comparison method is still the most effective quantitative method. In addition, test blocks can also be used to measure the sound speed and attenuation properties of the material.