Product Introduction
Hexagon head bolts manufactured to DIN 931, covering nominal diameters from M6 to M64 in standard metric coarse and fine thread series. When fully threaded shanks are required, DIN 933 complements the range. Both standards are supplied across property classes 4.8, 6.8, 8.8, 10.9, and 12.9 under ISO 898-1, with ASME B18.2.1 dimensional equivalents available for inch-based specifications. Surface finishes are selected to match service environment severity.

Material & Mechanical Properties
Forged from carbon or alloy steel and quench-and-tempered where the property class dictates. Proof load, tensile strength, and hardness are certified per heat lot with optional mill test reports. Classes 8.8 and 10.9 satisfy medium- and high-strength structural bolting requirements; class 12.9 meets demands for ultimate tensile strength above 1200 MPa.

Geometry & Thread Form
The bolt features a hexagonal head suitable for open-end, ring, or socket wrenches. Under-head body length is partially threaded per DIN 931; the plain shank provides shear plane alignment and improved fatigue performance in loaded joints. Coarse pitch metric threads to ISO 724 facilitate rapid assembly and resist stripping in common construction and machinery materials.

Corrosion Protection
Zinc electroplated per ASTM B633 or ISO 4042 as standard, with barrier-layer options including hot-dip galvanizing (ASTM A153), zinc flake, and PTFE-based topcoats for corrosive categories up to C5 per ISO 9223. Coating selection is matched to bolt strength class to eliminate hydrogen embrittlement risk.

Application Suitability
Used in general machinery, steel construction, automotive and transport assemblies, agricultural equipment, and plant engineering where a metric hex head bolt with a defined plain shank length is specified. DIN 931 bolts are standard components in pre-engineered connections, flange joints, and modular structural frames.