Home / Standards / GBT 39239-2020 GBT 39239-2020 Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities 无损检测 超声检测 不连续的特征和定量 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