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Anti-loosening nut (locking nut)
Anti-loosening nut is a nut that prevents the nut from loosening through special design.
Description
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Product definition and core types
Anti-loosening nut is a nut that prevents the nut from loosening through special design. Common types include:
Nylon insert anti-loosening nut (DIN985): built-in nylon ring, filling the thread gap by extrusion, excellent vibration resistance;
All-metal anti-loosening nut (DIN2510): generates continuous friction through elastic deformation or metal inserts, suitable for high temperature environment.
Core materials and characteristics
Material:
Nylon insert type: Q235 carbon steel + PA66 nylon, no red rust after 48 hours of salt spray test;
All-metal type: 35CrMoA alloy steel, surface plated with zinc or black, temperature resistance -56℃ to +170℃
Features:
Vibration resistance: Nylon insert type can withstand moderate vibration, and all-metal type is suitable for high-frequency vibration;
Removability: Nylon insert type can be reused 3-5 times, and all-metal type can be reused more times;
Environmental protection: Nylon insert is RoHS-compliant, and all-metal type is REACH-compliant.
Functions and applicable scenarios
Functions:
Prevent bolts from loosening due to vibration, impact or temperature changes;
Ensure the long-term reliability of key connections (such as engines and bridges).
Scenario:
Automobile engine (cylinder head bolts), mining machinery (crusher connection), wind power equipment (spindle flange).
Installation and maintenance
Installation:
Nylon insert type: Tighten according to the standard torque to avoid excessive extrusion of the nylon ring;
All-metal type: Use a torque wrench to ensure that the elastic deformation meets the requirements.
Maintenance:
Nylon insert type: Avoid using in high temperature (>120℃) or solvent environment;
All-metal type: Check the elastic parts regularly for fatigue and replace them in time.
Purchase suggestions
Select nylon insert type for normal vibration environment and all-metal type for high temperature vibration environment;
For high-precision scenarios such as aerospace, give priority to models certified by AS 9120 B.
Comparison and selection guide of the six major nuts
| Type | Electroplated galvanized flange nut | Electroplated galvanized nut | Colored zinc-plated nut | Anti-loosening nut | High-strength blackened nut | Welding nut |
| Core advantages | Dispersed pressure, anti-loosening | Low cost, strong versatility | High corrosion resistance, color identification | Anti-vibration, removable | High strength, high temperature resistance | Permanent connection, convenient |
| Salt spray test | 24-72 hours | 24-72 hours | 72-120 hours | 48 hours (nylon) | 48 hours without red rust | 48 hours (galvanized) |
| Applicable temperature | -20℃~80℃ | -20℃~80℃ | -20℃~100℃ | -56℃~170℃ (all metal) | -40℃~200℃ | -20℃~200℃ |
| Typical scenarios | Pipe flange, steel structure | General machinery, indoor environment | Outdoor equipment, humid environment | Engine, vibration equipment | High temperature machinery, vibration equipment | Automobile manufacturing, construction machinery |
| Installation method | Torque wrench tightening | Torque wrench tightening | Torque wrench tightening | Torque wrench tightening | Torque wrench tightening | Welding fixation |
| Environmental protection | Cyanide-free process complies with RoHS | Cyanide-free process complies with RoHS | Trivalent chromium is more environmentally friendly | Nylon complies with RoHS | No heavy metal pollution | No special requirements |
Selection suggestions:
High sealing requirements: electroplated zinc flange nut, with gasket to enhance sealing;
High corrosion environment: color-plated zinc nut, chromium-free passivation process is preferred;
Vibration environment: anti-loosening nut, all-metal type is suitable for high temperature scenes;
High temperature and high load: high-strength blackened nut, matched with 10.9 grade bolts;
Permanent connection: welding nut, projection welding or spot welding type is selected according to the process.
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