The categories of the bolts are:

1, The bolts according to the connection of connection: divided into ordinary and hinged holes.

2, The bolt according to the shape of the head points: have a hexagonal head, round head, square head, heavy head and so on.

3,Standard Bolts

Thread according to the length of the full thread and non-full thread two categories.

4, According to the thread of the tooth type is divided into coarse teeth and fine teeth two categories, coarse tooth type is not shown in the sign of the thread rod.

5.Bolts are divided into eight grades: 3.6,4.8,5.6,6.8,8.8,9.8,9.8,10.9 and 12.9. Grade 8.8 (including 8.8) bolts are made of low carbon alloy steel or medium carbon steel and heat treatment (quenching + tempering), commonly known as high strength bolts, below grade 8.8 (excluding 8.8) generally known as ordinary bolts.

6.Ordinary Aluminum Fasteners bolts.

7. can be divided into three grades A, B and C according to the production accuracy, A and B are refined bolts, and C are crude bolts.
Application
There are many names for bolts, everyone’s name may be different, some people called screws .

some people called bolts, some people called fasteners. Although there are so many names, but they all mean the same, all are bolts.
Bolts are a general term for the fasteners. Bolts are a tool to use the physical and mathematical principles of the circular rotation and friction of the inclined plane of an object.
Bolts in daily life and industrial production and manufacturing, is indispensable, bolts are also known as industrial rice. It can be seen that bolts are widely used.
The application scope of bolt Nuts And Washer

is: electronic products, mechanical products, digital products, power equipment, mechanical and mechanical products.