Product Description​
A Seismic Anti-Loosening Nut is a high-reliability fastener accessory designed to prevent bolt loosening under dynamic loads such as earthquakes, vibrations, and thermal expansion. Manufactured with 45# steel quenched and tempered (hardness HRC 28-32), this product features a double-nut locking structure with built-in anti-loosening threads, ensuring tight engagement with bolt threads and achieving an anti-loosening grade of ISO 16130 Class 4.​
One of the key features of this nut is its superior anti-loosening performance—after 100 million times of vibration testing, it remains locked without any loosening, outperforming traditional nuts by 5-8 times in anti-vibration capability. It is compatible with 8.8/10.9 grade high-strength bolts (M8-M36), making it suitable for seismic-resistant structures and vibration-prone equipment, such as bridges, wind turbine towers, industrial cranes, and high-speed rail track fasteners.​
For enhanced usability, the nut can be installed with ordinary tools (wrenches) without special equipment, and it is reusable without losing anti-loosening performance, reducing maintenance costs. The surface is treated with galvanizing + passivation or black oxide coating, providing good corrosion resistance and adapting to indoor and outdoor environments.​
With its compact design and easy installation, this anti-loosening nut is an essential accessory for improving structural safety and reliability. Whether it's for seismic reinforcement of existing buildings, fixing vibration-prone industrial equipment, or installing critical infrastructure (e.g., power transmission towers), this product provides a cost-effective and long-lasting anti-loosening solution.​
Customers can receive professional technical support, including compatibility testing with bolts and anti-loosening performance verification, ensuring optimal matching with project requirements.

Applications​
Seismic Anti-Loosening Nuts are critical fastener accessories for dynamic load and seismic-resistant projects. Certified by ISO 9001 and SGS vibration test reports, they ensure compliance with international anti-loosening standards, making them a trusted choice for high-safety requirements.​
These nuts are widely used in bridges (beam-column connections, guardrail fixing), wind turbine towers (flange connections, equipment fixing), industrial cranes (runway rail fixing, jib connections), high-speed rail track fasteners, seismic-resistant buildings (hospital, school frame connections), and vibration-prone equipment (pumps, motors, generators). Their ability to resist loosening under extreme vibrations and earthquakes makes them essential for critical infrastructure.​
The minimum order quantity is 100 pieces for standard specifications (M8-M36), and customized options are available for bolt size compatibility (M39-M48) and surface treatment (stainless steel 316L) to meet special project needs. Competitive pricing and bulk purchase discounts (for orders over 1000 pieces) enhance cost-effectiveness, while the short delivery time (2-5 workdays for standard orders) supports urgent maintenance and construction projects.​
With a monthly supply capacity of 5,000,000 pieces, the manufacturer ensures timely delivery even for large-scale infrastructure projects. The 45# steel quenched and tempered material and anti-corrosion surface treatment ensure long-term durability in various environments, from urban bridges to coastal wind farms.​
Customization options also include high-temperature resistant designs (up to 300℃) for industrial furnace equipment and low-temperature resistant designs (down to -40℃) for cold-region projects. Whether it's for new construction or old structure anti-loosening reinforcement, the Seismic Anti-Loosening Nut delivers reliable and long-lasting performance.