Home / Standards / GB/T 931-1988 GB/T 931-1988 Active Self-locking nuts，angle，anchor 角形托板自锁螺母 Standard Type GBT ICS 21.060.20 CCS J13 Status 现行 Issue Date 1988-12-22 Implementation 1989-07-01 Responsible Dept 中国机械工业联合会 Drafting Unit N/A