What are the requirements for the classification and quality of high-strength bolts?

1、 Classification of high-strength waste bolts

Friction type high-strength bolts: suitable for connecting steel frame beams and columns, solid web beam connections, heavy-duty crane beam connections in industrial buildings, brake systems, and important structures that bear dynamic loads.

Pressure bearing high-strength bolts: can be used for shear connections in static load structures that allow for a small amount of sliding or components that indirectly bear dynamic loads.

Tensile high-strength bolts: When the bolt is in tension, its fatigue strength is relatively low. Under dynamic load, its load-bearing capacity is not easy to exceed 0.6P (P is the allowable axial force of the bolt). Therefore, it is only suitable for use under static load, such as flange docking of compression members, T-joints, etc.

2、 Quality precautions for high-strength bolts

1. The surface rust, oil stains, burrs on the bolt hole wall, welding burrs, etc. should be cleaned up.

2. After treatment of the contact friction surface, it is necessary to meet the specified scratch resistance coefficient requirements. The high-strength bolts used should have matching nuts and washers, which should be used according to the matching requirements and should not be interchanged.

3. When installing the friction surface of the treated components, it is not allowed to be contaminated with oil, soil, and other debris.

4. During installation, the friction surface of the component should be kept dry and should not be operated in the rain.

5. Strictly inspect and correct the deformation of the connected steel plates before installation.

6. During installation, it is prohibited to hammer into the bolts to prevent damage to the bolt threads.

7. An electric wrench that is regularly tested during use to ensure torque accuracy and operate in the correct tightening sequence.

3、 Main safety technical measures for high-strength bolts

1. The opening size of the adjustable wrench should match the size of the nut, and a small wrench with a sleeve should not be used. When working at heights, a dead wrench should be used. If a live wrench is used, a rope should be used to secure it, and people should fasten their safety belts.

2. When assembling the connecting bolts of steel components, it is strictly prohibited to use hands to insert the connection surface or touch the screw holes. When removing and placing the pad iron plate, fingers should be placed on both sides of the pad iron plate.