DIN 7989 Flat Washers for Steel Construction
Flat washers for steel construction per DIN 7989 — heavy-thickness washers (8 mm nominal across the collected M10–M30 series) sized for HV bolt assemblies in structural steelwork, with hole and outer-diameter tolerances per size.
Last updated: 2026-11
Specifications
DIN 7989 is the washer of heavy steel construction: sized for high-strength HV bolt assemblies, with a nominal 8 mm thickness constant across the collected M10–M30 series (max 9.2 / min 6.8 mm) — far beyond ordinary flat washers, because a structural preload would dish a thin washer before the joint was fully tensioned. Hole and outer diameter carry max/min tolerances per size; the outer diameter stays compact relative to the thickness so washers seat on clustered flange and end-plate patterns. If your drawing names HV or heavy structural bolting, this is the matching washer family rather than a standard DIN 125.
| Standard | DIN 7989 — flat washers for steel construction |
|---|---|
| Thickness | 8 mm nominal (max 9.2 / min 6.8 mm) constant across the collected M10–M30 series |
| Size range | M10 through M30 — hole d max 11.7–34 mm, outer diameter dc max 20–56 mm |
| Duty | Heavy-thickness bearing for high-preload structural bolt assemblies in steelwork |
| Typical applications | HV structural connections, end plates, flange and clustered bolt patterns in structural steelwork |
| For thread diameter | d max (mm) | d min (mm) | dc max (mm) | dc min (mm) | h nominal (mm) | h max (mm) | h min (mm) | Weight (kg / 1000 pcs) |
|---|---|---|---|---|---|---|---|---|
| M10 | 11.7 | 11 | 20 | 18.7 | 8 | 9.2 | 6.8 | 13.8 |
| M12 | 14.2 | 13.5 | 24 | 22.7 | 8 | 9.2 | 6.8 | 19.4 |
| M16 | 18.2 | 17.5 | 30 | 28.7 | 8 | 9.2 | 6.8 | 29.3 |
| M20 | 22.84 | 22 | 37 | 35.4 | 8 | 9.2 | 6.8 | 43.7 |
| M22 | 24.84 | 24 | 39 | 37.4 | 8 | 9.2 | 6.8 | 46.2 |
| M24 | 26.84 | 26 | 44 | 42.4 | 8 | 9.2 | 6.8 | 62.1 |
| M27 | 30.84 | 30 | 50 | 48.4 | 8 | 9.2 | 6.8 | 78.9 |
| M30 | 34 | 33 | 56 | 54.1 | 8 | 9.2 | 6.8 | 101 |
Materials
- Material and finish specified per RFQ — the collected specification table covers geometry only
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 7989 Flat Washers for Steel Construction) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
Why is an 8 mm washer needed on a structural connection?
Because of the preload, not the load. High-strength structural bolts are tensioned to a large fraction of their yield, and the full clamp force passes through the washer under the rotated nut or head. A thin standard washer elastic-dishes under that pressure and the tension bleeds out of the joint; the DIN 7989 thickness — 8 mm nominal from M10 all the way to M30 — keeps the bearing annulus flat so the preload stays in the bolt. It is the same design logic as the ASTM F436 hardened washer on the inch side: the washer is part of the connection’s strength, specified and inspected with it.
What is the MOQ and lead time for this washer type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Confirm the exact schedule against quantity and size mix at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support