Home / Standards / GB/T 13680-1992 GB/T 13680-1992 Active Square weld nuts 焊接方螺母 Standard Type GBT ICS 21.060.20 CCS J13 Status 现行 Issue Date 1992-09-22 Implementation 1993-06-01 Responsible Dept 中国机械工业联合会 Drafting Unit N/A