The Emergence of Super Bolts
Large and extra-large machinery often requires bolt preloads up to 600kN, widely used in petrochemical, power generation, mining, metallurgy, transportation, and agricultural industries.
Traditional fasteners and tightening methods can no longer meet the connection demands of heavy-duty equipment.
Thus, the Super Bolt (Nut) was developed—ingeniously designed, safe, convenient, and highly reliable.
Its invention represents a revolution in bolt fastening technology.
Super bolts improve equipment integrity, extend service life, and simplify maintenance.
How Super Nuts Work
- Pre-tightening the jackscrews generates strong axial jacking force applied directly to a hardened washer. With a small friction diameter, high preload is achieved with relatively low torque.
- The load transfers to the main nut body, which is hand-installed onto the primary thread.
- Hardened washers transmit thrust while protecting the flange surface.
- Axial jacking force and main bolt reaction force create strong clamping force on the flange.
- The jacking force produces an equal and opposite reaction force on the main bolt.
How to Use Super Bolts
A Super Bolt consists of a central bolt and a main nut with multiple concentric small jackscrews.
Installation is simple:
- Hand-thread the main nut onto the bolt.
- Sequentially tighten the surrounding small jackscrews to complete fastening.
As the small jackscrews are tightened, they create reaction force via hardened washers, gradually increasing tension on the central bolt.
This structure delivers balanced, high-strength clamping.
Even under strong vibration, high temperature, and high pressure, Super Bolts maintain a secure, stable connection.
Preload Calculation of Super Bolts
Super bolts can generate preloads up to 10,000 tons, with material stress resistance up to 250,000 psi.
Within the elastic range, the relationship between preload F and tightening torque T is:
F=K⋅Dn⋅T
- n: number of jackscrews
- K: torque coefficient
- D: nominal thread diameter
More jackscrews, smaller diameter, lower friction, and smaller pitch all increase preload for the same torque.
Lubrication is recommended to reduce preload dispersion.
However, excessively small pitch or friction may cause thread shear or self-loosening.
Optimal design configuration is essential for performance and cost-effectiveness.
Advantages of Multi-Stage Jacking Super Bolts
- Easy installation with pneumatic or electric torque wrenches, saving operating time.
- Suitable for narrow spaces, harsh environments, and high-vibration equipment.
- Alloy steel construction delivers high strength, wear resistance, and stability under high temperature and pressure.
- No hydraulic power source needed; no issues like seal softening or aging.
- Excellent economy for large, heavy-duty connections.
- Higher fatigue strength than standard nuts; resistant to loosening and thread stripping.
- Reusable, long service life, safe and cost-effective.
Regular Bolts VS Super Bolts
Common Bolts
- Various strength grades are hard to identify on-site, risking misuse.
- Require extremely high torque, difficult to achieve with standard tools.
- Uneven tightening leads to uneven stress, breakage, and short service life.
- Loosening may cause equipment damage or safety incidents.
- High labor intensity, low efficiency, and expensive high-torque tools.
Super Bolts
- Simple installation using hand tools; installation time reduced by over 60%.
- No gas cutting or electric splitting required for disassembly.
- Greatly reduces downtime.
- Works in confined spaces and harsh conditions.
- Improves safety and efficiency.
- Reusable and reliable, helping prevent industrial accidents.
Conclusion
Super Bolt (jacking preload bolt) technology resolves major challenges in installation, disassembly, and preload control.
Only a standard torque wrench is required—no sledgehammers, heat, hydraulic tensioners, or wrenches needed.