How many grades are there for high-strength bolts? Below, the editor will introduce it to everyone. For those who don’t know about it, take the time to find out! There are four levels. There are 8.8 grades, 9.8 grades, 10.9 grades, and 12.9 grades. High-strength bolts are increasingly used. There are 8.8 and 10.92 mortar strength grades, among which 10.9 is the majority. Generally, the bolt strength grade is slightly lower, generally 4.4, 4.8, 5.6. High-strength bolts are mainly used in steel structure engineering construction. A very important feature of high-strength bolts is that they are limited to a single application. According to maijin, they are generally used for permanent connections, and repeated use is prohibited. The construction of high-strength bolts must first be screwed first and then finally screwed. For the initial screwing of high-strength bolts, an impact-type electric wrench or torque-adjustable electric wrench should be used; and there are clear regulations for final screwing of high-strength bolts. Torsional shear-type high-strength bolts must be screwed. The wire used for high-strength bolts is 45 steel or the like. When the heat treatment process is carried out on the screws, C1035 is used for hardening treatment. This hardening treatment method can generally achieve a high toughness of 22--32HRC. It can be said that the production of high-strength bolts has a very high level. Nowadays, high-strength bolts are widely used in industry and automobile manufacturing industry, and the production process regulations for such screws are becoming higher and higher.