Nut is nut, with bolt or screw screw is used to tighten affected parts, all manufacturing machine with a kind of component according to the material difference, divided into carbon steel, stainless steel, non-ferrous metal (such as copper) and so on several examples.
Gb nut is commonly used standard
Type GB41 Ⅰ hexagonal nut, class C
Type GB6170 Ⅰ hexagonal nut, grade A and B
Type GB6171 Ⅰ hexagonal nut, fine teeth, A and B
Thin hexagonal nuts -- class A, class B -- chamfered
Thin hexagonal nuts -- fine teeth -- class A and class B
GB6174 thin hexagonal nut -- class B -- no chamfer