Home / Standards / GBT 32.3-2020 GBT 32.3-2020 Hexagon head bolts with holes on head — Fine pitch thread 六角头头部带孔螺栓 细牙 Standard Type GBT ICS N/A CCS N/A Status N/A Issue Date N/A Implementation N/A Responsible Dept N/A Drafting Unit N/A