National standard number of plain nut:
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
GB6172 hexagon thin nut -- class A, B -- chamfer
GB6173 hexagon thin nut -- fine teeth -- class A and B
GB6174 hexagon thin nut - class B - no chamfer
Type GB6175 Ⅱ hexagonal nut, grade A and B
Type GB6176 Ⅱ hexagonal nut, fine thread - A and B
Hexagon flange nut - class A
GB55 hexagon thick nut
GB56 hexagon super thick nut
GB1229 large hexagon nuts (high strength for steel construction)
Common have national standard, British standard, American standard, Japanese standard nut. According to the different material, nut is divided into carbon steel, high strength, stainless steel, plastic steel and other types. According to the product attribute corresponding country different standard number is divided into ordinary, non-standard, (old) national standard, new national standard, American system, British system, German standard. Different sizes, threads are not divided into different specifications. General national standard, German standard M (such as M8, M16), the United States, the British system is used to express the number or # specification (such as 8#, 10#, 1/4, 3/8) fastener, nut is the mechanical equipment closely connected parts, through the inside of the thread, the same specification nut and screw, can be connected together, such as m4-0. 7 nut can only work with m4-0.