How to Distinguish High Strength Bolts

In order to distinguish high strength bolts, the following three methods are mainly used:
With naked eyes, high strength bolts can be divided into high-strength external hexagon bolts and high-strength inner hexagon bolts. These high strength bolts are generally marked with strength grade and hardness grade. Generally, the screw head is marked with bolt grade. For example, the external hexagon bolt has several performance levels of 3.6, 4.6, 4.8, 5.6, 5.8, 6.8, 8.8, 9.8, 10.9 and 12.9.
If there is no high strength bolt with these grades, it is difficult to see with naked eyes. But it doesn’t matter. We can make high-strength bolts according to what kind of screw wire is used. For example, screw wire 10101006, these two are ordinary grade screws, namely grade 4.8 screws, which are not high strength screws. However, if the screw is made of 1018, 10B21 and 45 steel, it belongs to high strength screw. Because the screws are produced with these screw wires. Later, some will be hardened to make the screw reach grade 8.8. Grade 8.8 screws are high strength bolts.
Of course, if the company’s conditions permit, it can be identified by testing the screw strength grade. The design of hexagon head bolt is the same as that of ordinary bolt, but the material is different. When m < = 24, 20MnTiB and 40B are used for high strength large hexagon head bolt, and the performance is 10.9 grade.
Now, you will be know how to distinguish high strength bolts.