EN 14399-3 High Strength Hex Nuts

EN 14399-3 High Strength Hex Nuts are designed for use in preloaded structural bolting assemblies, where controlled tightening is required to create a secure and reliable connection. They form part of the HR system and are used together with compatible high-strength bolts and washers in structural steel connections. These nuts are commonly used where bolted joints need to withstand high loads, vibration, and demanding service conditions. Proper selection of the nut, bolt, and washer as a complete system is important to achieve the required preload and connection performance.

EN 14399-3 nuts are suitable for steel structures, bridges, industrial buildings, heavy equipment, and other load-bearing assemblies. Size, property class, coating, and other requirements should be selected according to the project specification and the applicable EN 14399 system requirements. We can supply EN 14399-3 nuts in different metric sizes and surface finishes, with production and inspection according to the required specification. Mill Test Reports and quality documentation can also be provided for projects requiring batch traceability.

Specification:

EN 14399-3 High Strength Hex Nuts are designed specifically for System HR preloaded structural bolting assemblies. The nuts are supplied as part of a matched bolt, nut and washer system, where the components work together to achieve the required preload and connection performance. The standard covers metric sizes from M12 to M36 and specifies nut property classes 8 and 10. The appropriate nut class is selected according to the corresponding bolt grade and the required HR assembly configuration.

Mechanical Performance

For EN 14399-3 nuts, the mechanical properties are specified according to EN ISO 898-2, with property classes 8 and 10. The standard also gives specific proof-load requirements for the applicable thread sizes. For example, the proof load for an M20 nut is specified according to its property class rather than being treated as a generic high-strength nut. High-strength structural assemblies under EN 14399-3 are designed for preloaded joints, with the complete assembly intended to achieve a preload of at least 0.7 × fub × As in accordance with the relevant Eurocode requirements.

Dimension Chart of EN14399-3 High-strength Structural Hex Nut:

The EN 14399-3 dimension chart covers the key dimensions required for HR system high-strength nuts, including thread diameter, pitch, across-flats width, nut height, and other dimensional requirements. Standard sizes are available from M12 to M36, with the nut dimensions designed to work with the corresponding high-strength bolts and washers in the structural bolting assembly.

When selecting an EN 14399-3 nut, the thread size and property class should be matched with the corresponding bolt assembly. The nut should not be selected independently because EN 14399-3 is intended to be used as part of a complete preloaded structural bolting system. For projects requiring hot-dip galvanized or other protective finishes, the coating and thread condition should also be considered when checking the final dimensions and assembly compatibility. Custom requirements can be reviewed according to the project specification and applicable EN 14399 requirements.