DIN 933 Hex Bolts
Standard: DIN 933 / ISO 4017 (Fully Threaded)
Grade / Material: Steel Class 4.8, 8.8, 10.9, 12.9 / Stainless Steel A2-70, A4-80
Size Range: M3 to M52 (Custom lengths available)
Finish: Plain, Electro-Zinc, Hot-Dip Galvanized, Zinc Flake
Certification: EN 10204 3.1 Mill Test Certificate (MTC) provided
DIN 933 hex bolts are fully threaded metric hexagon head bolts specified for general fastening applications where full thread engagement is required along the entire shank length. Manufactured to DIN 933 (and its ISO successor ISO 4017), these bolts are available in steel grades 8.8, 10.9, and 12.9, as well as stainless steel A2-70 / A4-80, with a comprehensive range of surface finishes including plain, black oxide, electro zinc, hot-dip galvanized, and zinc flake coatings.
As a direct DIN 933 hex bolt manufacturer, we produce and export fully threaded hex head bolts from M3 to M52 (custom sizes available), with factory-direct pricing, batch-specific mill test certificates, and worldwide delivery. Whether you need Class 8.8 zinc-plated bolts for general construction or Class 10.9 high-strength bolts for machinery, we help you match the right grade and finish to your application.
Product Specifications
| Parameter | Specification |
|---|---|
| Standard | DIN 933 / ISO 4017 (Fully Threaded Hexagon Head Bolts) |
| Size Range | M3 to M52 (Custom sizes available) |
| Grade / Property Class | Carbon Steel: Class 4.8, 5.8, 8.8, 10.9, 12.9 Stainless Steel: A2-70 (304), A4-80 (316) |
| Thread | Metric coarse (Fine pitch available on request) |
| Surface Finish | Plain, Black Oxide, Electro Zinc (Clear/Blue/Yellow), Hot-Dip Galvanized, Zinc Flake |
| Coating Standards | ASTM A153, ISO 10684, ASTM B633, ISO 4042 |
| Product Class | Grade A (≤ M24), Grade B (> M24) |
| Packaging | Cartons, plastic bags, wooden pallets; custom labeling available |
| Customization | Special lengths, materials, coatings, and head markings upon request |
DIN 933 dimensions
Reference dimensions per DIN 933 / ISO 4017. Grade A applies to M3–M24; Grade B applies to M27 and above.
| Size | Width Across Flats (s) mm | Head Height (k) mm |
|---|---|---|
| M3 | 5.32 – 5.50 | 1.88 – 2.12 |
| M4 | 6.78 – 7.00 | 2.68 – 2.92 |
| M5 | 7.78 – 8.00 | 3.35 – 3.65 |
| M6 | 9.78 – 10.00 | 3.85 – 4.15 |
| M8 | 12.73 – 13.00 | 5.15 – 5.45 |
| M10 | 16.73 – 17.00 | 6.22 – 6.58 |
| M12 | 18.67 – 19.00 | 7.32 – 7.68 |
| M14 | 21.67 – 22.00 | 8.62 – 8.98 |
| M16 | 23.67 – 24.00 | 9.82 – 10.18 |
| M20 | 29.67 – 30.00 | 12.28 – 12.72 |
| M24 | 35.38 – 36.00 | 14.78 – 15.22 |
| M30 | 45.00 – 46.00 | 18.28 – 19.12 |
| M36 | 53.80 – 55.00 | 22.08 – 22.92 |
| M42 | 63.10 – 65.00 | 25.58 – 26.42 |
| M52 | 78.10 – 80.00 | 32.50 – 33.50 |
Note: DIN 933 has been withdrawn and superseded by ISO 4017. Key differences exist in width across flats for M10, M12, M14, and M22 between the two standards . Specify DIN or ISO dimensions at ordering.-5-7
Manufacturing Process
Our DIN 933 hex bolts are manufactured through six controlled steps:
1. Raw Material Selection
Wire rods or bars are verified for chemical composition and mechanical properties before production. Steel grades are selected to meet the target property class (8.8, 10.9, or 12.9).
2. Cold Forging / Hot Forging
Bolts are formed through cold heading (for smaller sizes) or hot forging (for larger diameters). The hex head and shank are shaped to near-net dimensions, improving grain flow and material utilization.
3. Thread Rolling
Threads are formed by rolling rather than cutting, which preserves the material's grain structure and increases fatigue resistance. Thread tolerance is maintained to 6g/6h per ISO 965.
4. Heat Treatment
For property classes 8.8, 10.9, and 12.9, bolts undergo quench-and-temper heat treatment to achieve the specified tensile strength, yield strength, and hardness.
5. Surface Finishing
Depending on the order, bolts receive the specified coating: electro zinc plating, hot-dip galvanizing, zinc flake, black oxide, or remain plain.
6. Inspection & Packaging
Finished bolts undergo dimensional verification, mechanical property testing, and visual inspection. Products are bulk-packed or retail-packed per customer requirements.
Quality Assurance & Testing
We operate a lot-by-lot release system—no shipment leaves without passing our full QC protocol.
Chemical composition by optical emission spectrometry (OES)
Mechanical properties (tensile strength, yield strength, elongation, hardness) per ISO 898-1 for steel classes
Dimensional inspection per DIN 933 / ISO 4017
Thread gauge inspection (GO/NO-GO per ISO 1502)
Coating thickness measurement (µm) per ISO 4042 / ASTM B633
Hydrogen embrittlement relief verification for high-strength plated bolts (Class 10.9/12.9)
Documentation provided: EN 10204 3.1 Mill Test Certificate (MTC) with heat number traceability, dimensional inspection report, and coating thickness report. Third-party inspection (SGS, TÜV, Bureau Veritas) can be arranged at buyer's request.
Applications
Construction & Structural Steel
Class 8.8 and 10.9 DIN 933 bolts are used in steel framing, brackets, and general structural connections where full thread engagement is beneficial.
Machinery & Equipment
Fully threaded bolts simplify assembly and allow adjustment across varying material thicknesses, making them ideal for machine frames, guards, and mounting applications.
Automotive & Transportation
Zinc flake and high-strength grades are specified for chassis, suspension, and under-hood fastening where corrosion resistance and fatigue life are critical.
Electrical & Telecom
Hot-dip galvanized DIN 933 bolts are standard for pole line hardware, cable trays, and outdoor equipment exposed to weathering.
Why Choose Us?
Full Thread Engagement, Verified
We understand that DIN 933 Hex Bolts is specified when thread length matters. Our production verifies thread run-out and full-length threading per the standard, ensuring no partial-thread substitutions.
Grade and Coating Matching
Tell us your application environment and load requirements. We'll recommend the appropriate property class and coating system—avoiding over-specification costs or under-specification failures.
DIN vs. ISO Clarity
We confirm whether you need DIN 933 (with its original spanner widths) or ISO 4017 (with revised widths for M10/M12/M14/M22) at quotation, preventing dimensional mismatches on assembly line .-5-7
Export-Ready Documentation
Mill test certificates, coating reports, and packing lists are prepared to your project requirements. We support third-party inspection and pre-shipment sample approval.
FAQ
Q1: What is the difference between DIN 933 and ISO 4017?
DIN 933 is the original German standard for fully threaded hexagon head bolts. ISO 4017 is the international successor. The DIN standard has been withdrawn, and key differences exist in width across flats for M10, M12, M14, and M22 . If your application requires original DIN spanner widths, specify DIN 933; otherwise ISO 4017 is the current reference.-5-7
Q2: What property class should I choose—8.8, 10.9, or 12.9?
Class 8.8 is the general-purpose grade for most structural and machinery applications. Class 10.9 offers higher tensile strength for demanding dynamic or high-load joints. Class 12.9 is for critical applications requiring maximum strength. Note that higher classes are more susceptible to hydrogen embrittlement if electro-plated—specify zinc flake or mechanical plating for Class 10.9/12.9 in corrosive environments.
Q3: Can you supply stainless steel DIN 933 bolts?
Yes. We supply A2-70 (304) and A4-80 (316) stainless steel fully threaded hex bolts. A4-80 is recommended for marine and chloride-containing environments.
Q4: What surface finishes are available for outdoor use?
For outdoor and industrial environments, hot-dip galvanizing (per ISO 10684 / ASTM A153) provides the thickest zinc barrier (typically 50–80 µm). Zinc flake coatings (Dacromet/Geomet type) offer excellent corrosion resistance without hydrogen embrittlement risk and are preferred for high-strength bolts. Electro zinc plating is suitable for indoor or lightly corrosive conditions.
Q5: Do you provide mill test certificates?
Yes. EN 10204 3.1 MTC is standard with every shipment, documenting chemical composition, mechanical properties, and heat number traceability. 3.2 certification can be arranged upon request.
Q6: What is your MOQ and lead time?
MOQ varies by size and grade—typically 500–1,000 pieces for standard sizes. Lead time is 2–3 weeks for stock items; 4–6 weeks for custom lengths, coatings, or non-standard materials. Confirmed at quotation.
Contact Us
Looking for a reliable DIN 933 Hex Bolts supplier or ISO 4017 fully threaded bolt manufacturer?
Whether you need bulk quantities of Class 8.8 zinc-plated hex bolts for structural steel, Class 10.9 high-strength bolts for heavy machinery, or hot-dip galvanized metric bolts for outdoor infrastructure, our engineering and export team is ready to support your project.
