Home / Standards / GB/T 31940-2025 GB/T 31940-2025 Active Bi-metal composite steel pipes for fluid transportation 输送流体用双金属复合钢管 Standard Type GBT ICS 77.140.75 CCS H48 Status 现行 Issue Date 2025-08-01 Implementation 2026-02-01 Responsible Dept 中国钢铁工业协会 Drafting Unit N/A