A563 Heavy Hex Nut | Grade DH for A325 A490 Bolt
TheA563 Heavy Hex Nut is a heavy hex pattern nut manufactured to ASTM A563 specification, designed specifically to mate with A325 and A490 high-strength structural bolts. Unlike a standard hex nut with smaller width across flats, the Carbon Steel Heavy Nut features increased bearing surface and higher proof load capacity, making it the required nut type for all A325 and A490 structural bolting assemblies in ship hull framing, deck equipment mountings, and crane rail baseplate connections.
Available in Grade A, B, C, and DH configurations, the A563 series covers carbon steel and weather-resistant alloy steel variants. Grade DH offers the highest strength level with minimum proof stress of 120 ksi, suitable for critical hull structure splice plates and primary framing connections. For corrosive marine environments, Stainless Steel Heavy Nut variants in SS304 and SS316 provide enhanced chloride resistance, while HDG (hot-dip galvanized) finishes deliver 480+ hours salt spray protection per ASTM B117. The A563 Hex Bolt assembly (using A325/A490 bolts) with matching A563 heavy hex nuts forms the primary structural connection system throughout modern shipbuilding.
| Product Name | A563 Heavy Hex Nut / Carbon Steel Heavy Nut |
| Standard | ASTM A563 / ASME SA563/ A563 Grade DH |
| Type | Heavy Hex Nut Grade A / B / C / DH |
| Size Range | 1/4"– 4"(M6 – M100 available on request)（A563 heavy hex nut dimensions） |
| Material | Carbon Steel / Weathering Steel / SS304 / SS316 |
| Grade / Strength | Grade A (90 ksi) / B (120 ksi) / C (120 ksi) / DH (120 ksi) |
| Surface Finish | Plain / HDG (Hot-Dip Galvanized) / Zinc Plated / Dacromet |
| Paired Bolt | A325 / A490 / F3125 Grade A / Grade B |
| Proof Load (DH) | ≥ 120,000 psi (827 MPa) |
| Application | Hull Structure / Deck Crane Rail / Equipment Baseplate / Splice Plate |
| Certification | EN 10204 3.1 / LR / DNV / BV / ABS (on request) |
SINOFASTENER supplies A563 heavy hex nuts with full heat number traceability and EN 10204 3.1 mill test certification. Each batch is dimensionally inspected per ASME B18.2.2 and proof load tested per ASTM A563. For projects requiring Stainless Steel Heavy Hex Nut alternatives or custom non-standard sizes beyond the standard range, contact our technical team for material selection and availability confirmation.
E-mail: sales@sinofastener.com | SINOFASTENER
