GB/T 39241-2020 in English

Analysis of the core content of the standard

This standard adopts ISO 16823:2012, focusing on the application of ultrasonic penetration technology in defect detection and material attenuation determination. The main technical differences include: adding the definition of transmission attenuation technical terms, optimizing the attenuation coefficient calculation formula (Formula 1-3), adjusting the reference file system, etc.

Technical Framework Comparison

Key Technology Implementation Points

1. Detection Configuration Selection

According to Table 1, the single-probe solution is suitable for reflection detection scenarios (configuration ad), and the dual-probe solution is more suitable for penetration detection (configuration eh). For thin workpieces, it is recommended to use a probe with a frequency of ≥5MHz.

2. Sensitivity Setting Specifications

Article 5.2 of the standard clearly stipulates that the amplitude of the penetration signal should reach 80% of the full screen height during manual detection. It is recommended to use a reference test block with similar acoustic characteristics to the test piece, and the coupling agent thickness should be controlled at 0.05-0.1mm.

Attenuation coefficient determination method

Comparison of measurement technologies

• Comparison technology: The attenuation coefficient of the reference test block needs to be known, and it is suitable for laboratory environment
• Liquid immersion technology: The sound path needs to be greater than 3 times the near-field length, and it is suitable for on-site detection

Implementation suggestions

1. For thin plates with a thickness of less than 3mm, it is recommended to use a high-frequency probe of more than 10MHz
2. When testing curved workpieces, a special probe fixture should be designed to ensure the coincidence of the sound beams
3. Regularly check the coupling status, and re-couple when the signal fluctuation exceeds ±2dB