EN 14399-10（HRC） Preloaded bolting assemblies
The EN 14399-10 bolt is a high-performance structural fastener manufactured in accordance with the European standard for high-strength structural bolting assemblies for preloaded joints. This specific part of the EN 14399 series covers"System HRC"— a calibrated bolt and nut assembly designed to achieve the required preload and ductility predominantly by plastic elongation of the bolt itself. The standard specifies dimensions, materials, mechanical properties, and testing requirements for bolt assemblies ranging from M12 to M36 in diameter, ensuring consistent quality and reliable performance in critical steel connections.
As a High strength preloaded bolt assembly, this product is engineered to create friction-type connections where the clamping force between connected steel members resists shear forces, rather than relying on bolt shank shear or bearing. The assembly achieves its high preload through controlled tightening methods, typically using torque-controlled or angle-controlled tightening procedures, which ensure accurate tension application. These assemblies are mandatory for use in European structural steel projects where safety and performance cannot be compromised. They provide superior resistance to fatigue, vibration, and dynamic loading, making them essential for structures subjected to repeated or fluctuating stresses.
The System HRC bolt set is a complete fastening solution that includes a specially designed bolt, nut, and washer(s) — all manufactured by the same supplier to guarantee compatibility and system performance. Unlike System HV, which derives ductility from thread deformation, System HRC achieves required ductility through controlled plastic elongation of the bolt, providing a different mechanical behavior suitable for specific structural applications. These bolt sets are typically grade 10.9 or 12.9, offering exceptional tensile strength and hardness. They are widely used in high-rise buildings, long-span bridges, wind turbine towers, stadiums, heavy industrial plants, and other critical infrastructure projects across Europe. All components are marked with the manufacturer's identification and the EN standard reference, ensuring full traceability and compliance with CE marking requirements under the Construction Products Regulation
