The difference between high-strength bolts and ordinary bolts

The difference between high-strength bolts and ordinary bolts

High strength bolts are increasingly widely used. Two strength levels, 8.8s and 10.9s, are commonly used, with 10.9 being the most common. universal

The strength level of through bolts should be low, generally 4.4, 4.8, 5.6, and 8.8 levels.

From the perspective of raw materials:

High strength bolts are made of high-strength materials. The screws, nuts, and washers of high-strength bolts are all made of high-strength steel,

Commonly used are 45 steel, 40 boron steel, and 20 manganese titanium boron steel. Ordinary bolts are commonly made of Q235 steel.

2. From the perspective of strength level:

High strength bolts are increasingly widely used. Two strength levels, 8.8s and 10.9s, are commonly used, with 10.9 being the most common. universal

The strength level of through bolts should be low, generally 4.4, 48, 5.6, and 8.8 levels.

From the perspective of force characteristics:

High strength bolts apply pre tension and transmit external forces through friction, while ordinary bolt connections rely on bolt rods for shear resistance and hole wall pressure bearing

When transmitting shear force and tightening the nut, the pre tension generated is very small, and its impact can be ignored. However, high-strength bolts, besides their strong material

In addition to a high degree of rigidity, a large pre tension force is also applied to the bolts, causing squeezing force between the connecting components, thereby making them perpendicular to the screw direction

There is a significant frictional force, and pre tension, anti slip coefficient, and steel type all directly affect the bearing capacity of high-strength bolts.

According to the stress characteristics, it is divided into pressure bearing type and friction type, and the calculation methods for the two are different. Minimum specification M12 for high-strength bolts, commonly used

M16~M30, oversized bolts have unstable performance and should be used with caution in design.