Home / Standards / GB/T 4957-2025 GB/T 4957-2025 Active Non-conductive coatings on non-magnetic electrically conductive base metals—Measurement of coating thickness—Amplitude-sensitive eddy-current method 非磁性导电基体金属上非导电覆盖层 覆盖层厚度测量 振幅敏感涡流法 Standard Type GBT ICS 25.220.40;25.220.50 CCS A29 Status 现行 Issue Date 2025-10-31 Implementation 2026-05-01 Responsible Dept 中国机械工业联合会 Drafting Unit N/A