This standard specifies cross recessed countersunk head screws with thread specifications M1.6~M10, performance grade 4.8, H type and Z type cross recess, and product grade A grade.
GB/T 819.1-2000 history
2016GB/T 819.1-2016 Phillips countersunk head screws - Part 1: Class 4.8
2000GB/T 819.1-2000 Countersunk flat head screws(common head style)with cross recess-Part 1:Steel of property class 4.8