Home / Standards / GBT 2670.2-2017 GBT 2670.2-2017 Hexalobular socket countersunk head tapping screws 内六角花形沉头自攻螺钉 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