Home / Standards / GB/T 3639-2021 GB/T 3639-2021 Active Seamless cold-drawn or cold-rolled steel tubes for precision applications 冷拔或冷轧精密无缝钢管 Standard Type GBT ICS 77.140.75 CCS H48 Status 现行 Issue Date 2021-08-20 Implementation 2022-03-01 Responsible Dept 中国钢铁工业协会 Drafting Unit 中国钢铁工业协会