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Electrogalvanized nuts
Electrogalvanized nuts are the most common standard nuts. A zinc layer is deposited on the surface of carbon steel through an electrolytic process. The surface is silvery white or bluish white, and has both anti-corrosion and decorative functions. Its structure includes a hexagonal head, a threaded section, and a galvanized layer, which complies with GB/T 6170 and other standards.
Description
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Product definition and structure
Electrogalvanized nuts are the most common standard nuts. A zinc layer is deposited on the surface of carbon steel through an electrolytic process. The surface is silvery white or bluish white, and has both anti-corrosion and decorative functions. Its structure includes a hexagonal head, a threaded section, and a galvanized layer, which complies with GB/T 6170 and other standards.
Core materials and features
Material: Q235 carbon steel (conventional), 35CrMoA alloy steel (high strength), galvanized layer thickness 5-12μm, neutral salt spray test 24-72 hours without white rust.
Features:
Economical: low cost, mature technology, suitable for large-scale procurement;
Compatibility: used with electrogalvanized bolts to avoid electrochemical corrosion;
Lightweight: low density of zinc layer, suitable for weight-sensitive equipment (such as consumer electronics).
Function and applicable scenarios
Function:
General mechanical connection (such as motor, reducer);
Temporary or semi-permanent installation, easy disassembly.
Scenario:
Household appliances (such as washing machines, air conditioners), office equipment (such as table and chair frames), temporary buildings (such as scaffolding).
Installation and maintenance
Installation:
When used with standard bolts, tighten according to torque requirements (such as the torque value of 4.8 grade bolts refers to GB/T 3098.2);
Avoid direct contact with active metals such as aluminum and magnesium to prevent galvanic corrosion.
Maintenance: Check the tightness of the nuts regularly, and the damaged parts of the galvanized layer can be treated with anti-rust spray.
Purchase suggestions
Select hot-dip galvanized nuts for outdoor or humid environments (salt spray test ≥100 hours);
For high-precision equipment, it is recommended to select Class A products (tolerance ±0.1mm).
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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