The core structure of the hydraulic nut includes a steel body with internal threads, a piston, and a seal ring.

Fitting and aligning: Screw the hydraulic nut onto the bolt until it contacts the support surface.

Pressurizing: Inject hydraulic oil into the nut’s oil chamber through an external high-pressure pump.

Stretching: The oil pressure pushes the piston, generating a tremendous axial thrust that physically elongates the bolt.

Locking: After the bolt is elongated, manually tighten the locking ring on the nut body (mechanical locking), or maintain pressure.

Depressurizing: Release the oil pressure, and the bolt, due to elastic recovery, firmly clamps the flange or joint.