| Standard | ASME B18.16.4 |
| Grade | 10.9，12.9 |
| Surface Treatment | HDG |
Product Introduction
Standard Name: Serrated Flange Hexagon Nut (Heavy Series)
Common Names: Serrated Flange Locking Nut, Large Flange Locking Nut, Heavy-Duty Anti-Rotation Flange Nut
Product Definition: The large serrated flange locking nut is an integrated heavy-duty fastener combining a flange plate with a serrated locking mechanism. Its flange base features precision-stamped, radially distributed serrations (typically bidirectional) that bite into the mating surface. This creates powerful anti-rotation resistance through mechanical interference, specifically designed for permanently locking large-diameter bolts (typically M20 to M64 and above) under extreme vibration and heavy-load conditions.
Key Features
Superior Anti-Loosening Performance: Hardened serrations on the flange base bite into the contact surface during tightening, creating a mechanical interlock that delivers vibration-resistant locking far exceeding standard nuts.
High Preload and Load Distribution: The integrated wide flange provides a larger bearing area, evenly distributing loads to effectively protect connected surfaces and reduce crushing risks.
Integrated Washer-Free Design: Eliminates the need for additional spring washers or flat washers, simplifying assembly, reducing parts management costs, and eliminating the risk of missing washers.
Ultra-High Strength and Durability: Manufactured from premium alloy steel and heat-treated to achieve high-strength performance grades, capable of withstanding extreme axial tensile and shear forces.
Heavy-Duty and Harsh Environment Suitability: Specifically engineered for extreme conditions in heavy industrial sectors such as wind turbine towers, mining machinery, and large steel structures.
Working Principle
This nut achieves locking through the principle of “mechanical interlocking”:
Sawtooth Engagement Phase: When the nut is tightened to the specified torque, its heat-treated, sharp, high-strength sawtooth edges at the flange base are forcibly pressed into and “cut into” the surface of the workpiece (or washer surface) it contacts under immense axial preload.
Anti-rotation Locking Stage: Once embedded, the serrations function like countless micro-wedges, creating formidable circumferential (rotational) resistance. Any vibration or alternating load attempting to reverse-rotate the nut must overcome immense shear forces and friction between the serrations and the material, achieving an inherently mechanical lock.
Product Applications
Renewable Energy: Flange connections for wind turbine towers, blade bearing connections.
Heavy Construction Machinery: Chassis, slewing bearings, and critical structural connections for mining trucks, large excavators, and crawler cranes.
Rail Transportation: Fast rail and heavy-haul railway track fastening systems, bogie and main beam connections.
Large Steel Structures: Structural node connections for bridges, stadiums, and high-rise buildings.
Marine and Offshore Engineering: Critical fastening for deck machinery, mooring equipment, and offshore platforms.
Pressure Vessels and Piping: Bolted connections for large flanges.
