DIN 933 Hexagon Head Bolt with Full Thread – Metric Coarse, Property Classes 4.8 to 12.9

This product is a metric hexagon head bolt manufactured to DIN 933 (withdrawn, superseded by ISO 4017), featuring a fully threaded shank from head to tip. Thread sizes range from M1.6 to M52 with ISO metric coarse pitch and thread tolerance class 6g. Available in carbon steel and alloy steel grades including Q235, 35#, 45#, 40Cr, and 35CrMo, with property classes 4.8, 5.8, 8.8, 10.9, and 12.9 per ISO 898-1, and stainless steel A2-70, A4-70, and A4-80 per ISO 3506. Surface finishes include plain, zinc plating (clear, blue, yellow), hot-dip galvanizing, black oxide, Dacromet, and Geomet. Used in through-bolted joints, pre-tapped blind holes, and variable clamp thickness assemblies where full thread engagement is required along the entire bolt length.

What are the dimensional specifications and product grades for DIN 933 hexagon head bolts?

DIN 933 is split into product grade A (threads M1.6 to M24, lengths ≤ 10d or 150 mm, whichever is shorter) and product grade B (threads > M24, or lengths > 10d or 150 mm). Key dimensions include: width across flats (s) for M6 = 10.00 mm, M8 = 13.00 mm, M10 = 16.00 mm, M12 = 18.00 mm, M16 = 24.00 mm, M20 = 30.00 mm, M24 = 36.00 mm, M30 = 46.00 mm, M36 = 55.00 mm. Head height (k) ranges from 4.0 mm (M6) to 22.5 mm (M36). Thread length equals the full bolt length under the head per DIN 933 specification. ISO 4017 supersedes DIN 933 with changed spanner widths for M10, M12, M14, and M22.

What are the mechanical property requirements for each property class?

Property class 4.8: minimum tensile strength 400 MPa, yield strength 320 MPa, from low/medium carbon steel. Class 8.8: tensile 800 MPa, yield 640 MPa, quenched and tempered from medium carbon steel. Class 10.9: tensile 1040 MPa, yield 940 MPa, from alloy steel quenched and tempered. Class 12.9: tensile 1220 MPa, yield 1100 MPa, from alloy steel with hardness 39–44 HRC. Stainless steel A2-70: tensile 700 MPa, yield 450 MPa from AISI 304. A4-80: tensile 800 MPa, yield 600 MPa from AISI 316 cold-worked. The standard specifies a defined coefficient of friction μ(total) = 0.12–0.18 for elements with nominal tensile strength ≥ 800 MPa.

What are the marking, traceability, and certification requirements for DIN 933 bolts?

Each bolt head must be permanently marked with the property class (e.g., 8.8, 10.9, 12.9), the manufacturer's identification mark, and for stainless steel grades the material grade (A2 or A4) and strength class (-70 or -80) per ISO 3506. Full traceability is maintained from mill certificate to shipment, with dimensional inspection (100% check of width across flats, head height, thread length, radius under head) and Go/No-Go thread gauging on every batch. EN 10204 Type 3.1 inspection certificates are available for common sizes, providing test results from specific tests on the delivery batch itself. For on-site use, the fully threaded configuration is preferred for pre-tapped blind holes, thin-gauge flanges, and variable stack-up assemblies where the exact grip length is unknown at the design stage. Note that fully threaded bolts have lower shear capacity along the threaded portion compared to the smooth shank of a partial-thread bolt (DIN 931/ISO 4014); the partial-thread variant is preferred for structural bolted joints where shear strength is critical.