The Difference Between High-strength Bolts And Ordinary Bolts, And The Classification Of High-strength Bolt Grades

High strength bolts and ordinary bolts are two commonly used connecting components in fields such as building structures. High strength bolts are generally used for connecting components that require significant preload, such as bridges, high-voltage equipment, etc; Ordinary bolts are widely used in many components that need to be connected. So, what are the obvious differences between high-strength bolts and ordinary bolts?

1. Differences in raw materials

High strength bolts are manufactured using high-strength materials. The screw, nut, and washer of this type of bolt are all made of high-strength steel, commonly used including 45 steel, 40 boron steel, 20 manganese titanium boron steel, and other steels. Ordinary bolts are made of ordinary carbon structural steel and do not undergo heat treatment.

2. Differences in strength levels

High strength bolts generally use two strength levels: 8.8s and 10.9s, with 10.9 being the most common. However, the strength level of ordinary bolts is lower, generally using grades 4.4, 4.8, 5.6, and 8.8.

3. Differences in force characteristics

Ordinary bolt connections rely on the shear resistance of the bolt rod and the pressure bearing capacity of the hole wall to transmit shear force, while high-strength bolts not only have high material strength, but also apply a large pre tension force to the bolts, causing squeezing pressure between the connecting components, and thus creating a large frictional force perpendicular to the screw direction.

4. Differences in Use

The bolted connections of the main components of building structures are generally made with high-strength bolts. Ordinary bolts can be reused, while high-strength bolts cannot be reused. High strength bolts are generally used for permanent connections.

In addition, high-strength bolts also have the following characteristics:

The connection joint of high-strength bolts has high reliability and safety, and can withstand large loads and impact forces.

2. The pre tightening force of high-strength bolts can effectively control the deformation of connecting components, improve the tightness and stiffness of the connection, and ensure the stability and safety of the connection.

3. The stress distribution of high-strength bolts is more uniform than that of ordinary bolts, which can effectively reduce the fatigue life of the parts.

4. High strength bolt connections have high tightening strength and will not cause problems such as looseness and deformation, which can improve the service life of equipment and structures.

Overall, high-strength bolts have higher strength and a wider range of applications, which can meet higher connection requirements and safety requirements. Ordinary bolts are suitable for some basic connection needs, such as home decoration. In the specific application process, different bolt types and specifications need to be selected based on the actual situation and technical specifications.