Expansion bolts are primarily used for fastening and securing objects to hard substrates such as concrete, brick walls, and rock. They are widely used in construction, decoration, and mechanical equipment installation. Their main applications include:

1. Construction Engineering: Used for securing steel structures, railings, curtain walls, doors and windows, scaffolding, and equipment foundations.
2. Interior Decoration: Used for installing ceilings, air conditioners, TV mounts, cabinets, bathroom fixtures, etc.
3. Mechanical Equipment: Used for installing various machinery, brackets, pipelines, and tracks, providing stable support.
4. Bridges and Roads: Used for securing bridge railings, road signs, traffic lights, and barriers.
5. Power and Telecommunications: Used for installing substations, cable trays, and communication base stations.
6. Household Maintenance: Used for hanging heavy objects in home renovations, such as water heaters, chandeliers, and paintings.

The working principle of expansion bolts is that when the bolt is tightened, the expansion sleeve expands, firmly gripping the substrate to achieve a secure anchoring effect.