This standard specifies the hexagonal head bolts with holes in the head of thread specifications M8×1~M48×3, A and B grades. The bolt is made of a wire hole in the head of GB5785.
GB/T 32.3-1988 history
2020GB/T 32.1-2020 Hexagon bolts with wire holes on head
1988GB/T 32.1-1988 Hexagon bolts with wire holes on head--Product grade A and B