Product Introduction
Carbon steel hexagon flange bolts with a serrated bearing face under the head. The integrated circular flange acts as a captive washer, while the serrations embed into the mating surface to create a mechanical lock that resists vibration-induced loosening. Sizes M5 through M20 are supplied in metric coarse thread; property classes 8.8, 10.9, and 12.9 per ISO 898-1. Suitable for use with standard hex nuts or directly in tapped assemblies.

Material & Mechanical Properties
Forged from medium carbon steel and quench-and-tempered to achieve the specified tensile and proof load values. Mechanical certification is provided by lot, traceable to heat number. Classes 8.8 and 10.9 cover general high-strength bolting; class 12.9 is specified where tensile strength exceeding 1200 MPa is required. The carbon steel substrate delivers the toughness needed for dynamic and impact-loaded joints.

Geometry & Thread
Hexagonal wrenching head dimensioned to standard DIN/ISO wrench sizes. The flange underside carries annular serrations that bite into the mating surface during tightening, generating prevailing-torque resistance to rotation. Flange diameter distributes clamp load and prevents the fastener head from embedding in softer structural materials. Metric coarse pitch thread to ISO 724 allows rapid assembly and resists stripping.

Corrosion Protection
Zinc electroplated per ASTM B633 (Fe/Zn 5–8 µm) with clear passivation as standard, offering reliable corrosion resistance for indoor and sheltered outdoor environments. For exposed structural applications and higher corrosivity categories, zinc-nickel, zinc flake, or hot-dip galvanized finishes are applied. Coating selection considers hydrogen embrittlement limits for each property class.

Application Suitability
Heavy machinery, engine and chassis components, conveyor systems, and industrial equipment where vibration-induced loosening risks joint integrity. The serrated flange design eliminates the need for separate locking washers or threadlocking compounds, reducing part count and assembly time. Compatible with hex nuts of matching property class and with tapped holes in steel and cast iron.