What is the standard for hex socket bolts?

Update:16-11-2018
Summary:

The standards for the implementation of hexagon socket […]

The standards for the implementation of hexagon socket bolts are GB70.1, IOS04762, and DIN912. The materials are mainly carbon steel, alloy steel and stainless steel. The unit introduced is mm.
The hexagon socket head bolt size is M1.6, the head diameter is the maximum, the non-knurling is 3, the knurling is 3.14; the head diameter thickness is 1.6; the inner hexagon is 1.5; the hexagonal depth is 0.7. The thread length is 15.The hexagon socket head bolt size is M2, the head diameter is the maximum, the knurling is 3.8,China Hex Bolts, the knurling is 3.98; the head diameter thickness is 2; the inner hexagon is 1.5; the hexagonal depth is 1. The length is 16.

The hexagon socket head bolt size is M2.5, the head diameter is the maximum, the non-knurling is 4.5, the knurling is 4.68; the head diameter thickness is 2.5; the inner hexagon is 2; the hexagonal depth is 1.1. The thread length is 17.Hexagon socket head bolts are M3, the head diameter is the maximum, 5.5 is not knurled, 5.68 is knurled; the maximum thickness of the head diameter is 3; the opposite side of the hexagon is 2.5; the depth of the hexagon is 1.3; The length is 18.

Hexagon socket head bolts are M4, the head diameter is the maximum, 7 is not knurled, 7.22 is knurled; the maximum thickness of the head is 4; the inner hexagon is 3; the hexagon is 2; The length is 20.The hexagon socket head bolt size is M5, the head diameter is the maximum, the knurling is 8.5, the knurling is 8.72; the head diameter thickness is 5; the inner hexagon is 4; the hex is 2.5; The length is 22.