This national standard specifies the characteristics of slotted countersunk flat head screws of product grade A and with threads from Ml.6 to Ml0 inclusive, performance grade 4.8, 5.8, A2-50, A2-70, CU2, CU3 and AL4.
If, in special cases, specifications other than those listed in this national standard are required, they should be selected from existing International Standards, for example GB/T 196, GB/T 3106, GB/T 3098.1, GB/T 3098.6, GB/T 3098.10 and GB/T 3103.1.