Technical requirements and scope of the EN 1665 standard
The European standard EN 1665 establishes strict technical regulations for high-strength hexagon bolts with flange (heavy series). This fastening nomenclature covers a metric thread range from M5 to M20. Products are classified by strength classes 8.8, 10.9, and the corrosion-resistant version A2-70.
The engineering potential of fasteners according to the EN 1665 standard allows them to be used in critical metal structure assemblies and machinery equipment subject to significant static and dynamic loads. The use of a flange head provides an increased bearing area, which minimizes the risk of material deformation in the clamping zone and eliminates the need for additional washers.
EV Group China experts recommend choosing the strength class based on operating conditions: 8.8 and 10.9 bolts are optimal for loaded structural frames, while the A2-70 version is intended for aggressive environments where high oxidation resistance is required.