GB/T 44512-2024 in English

1. Background and significance of standard formulation

With the widespread application of large-scale amusement facilities, their safety and reliability have become the focus of public attention. Key components such as steel structures, bolts and shafts may break due to stress overload or fatigue during long-term use, leading to serious safety accidents. Ultrasonic stress testing, as a non-destructive detection method, can monitor the stress state of these components in real time and provide a scientific basis for the safe operation of amusement facilities.

2. Principle of ultrasonic stress testing technology

Ultrasonic stress tester is based on the principle of acoustic elasticity and calculates stress values by measuring the change in the propagation time of ultrasonic waves in materials. Specifically, when a material is subjected to stress, the propagation speed of ultrasonic waves will change due to the influence of stress. By comparing the difference in ultrasonic propagation time under stress and stress-free states, the stress value of the tested component can be accurately calculated.

3. Requirements for test instruments and equipment

The test instrument must meet the following basic requirements:

• Acoustic time measurement accuracy: The resolution should not be less than $1\mathrm{ns}$.
• Sound velocity display function: It can display the sound velocity of the object being measured in real time.
• Stress calculation capability: It supports megapascal ($\mathrm{[MPa]}$) unit display.

It is recommended to use ultrasonic stress tester in combination with a special probe for testing to ensure measurement accuracy and reliability.

4. Implementation suggestions and precautions

In actual applications, it is recommended to take the following measures:

1. Calibration sample selection: Calibration samples with the same material and surface condition as the workpiece being measured should be used preferentially.
2. Couplement selection: Select the appropriate couple according to the test method. It is recommended to use a special couple with higher viscosity for shear waves when measuring axially.
3. Environmental control: The test environment temperature should be controlled at $5~^{\circ}\mathrm{C}\sim40~^{\circ}\mathrm{C}$, and the temperature difference with the calibration should not exceed $\pm5~^{\circ}\mathrm{C}$.

In addition, the test personnel must have relevant qualifications and strictly perform the calibration, verification and period verification procedures in accordance with the requirements of GB/T34370.1 and GB/T34370.5.