Home / Standards / GBT 39849-2021 GBT 39849-2021 Non-destructive testing instruments — Ultrasonic time-of-flight diffraction detector — Performance test methods 无损检测仪器 超声衍射声时检测仪 性能测试方法 Standard Type GBT ICS N/A CCS N/A Status N/A Issue Date N/A Implementation N/A Responsible Dept N/A Drafting Unit N/A