Home » Chamfered Square Nuts (DIN 557) - Marine Stainless Steel (A4)

Chamfered Square Nuts (DIN 557) - Marine Stainless Steel (A4)

Chamfered Square Nuts (DIN 557) — Marine Stainless Steel A4 (SUS316)

FULLERKREG DIN 557 chamfered square nuts in A4 marine-grade stainless steel (SUS316 / AISI 316) deliver superior resistance to chloride-induced corrosion, making them the preferred choice for offshore, marine, coastal, chemical, and food-processing environments. The chamfered top face ensures clean seating and simplified assembly. Manufactured to DIN 557 geometry with pickled and passivated surface finish for maximum corrosion protection.

Product Specifications

Property Details
Standard DIN 557
Type Chamfered Square Nut
Material Marine Stainless Steel SUS316 (A4)
Surface Treatment Pickled & Passivated (Bright Finish)
Thread Type Metric Coarse Thread (ISO 68-1)
Size Range M5 – M16
RoHS Compliant Yes
Magnetic Properties Non-magnetic (austenitic; minimal cold-work effect vs. A2)

Dimensional Data (DIN 557 · Unit: mm)

Thread Size
d		 Pitch
(mm)		 Nut Height m (mm) Min Wrenching
mw (mm)		 Across Flats s (mm) Across Corners e (mm) Bearing Dia.
dw min (mm)		 Est. Unit Weight
(g/pc)
max min max min max min
M5 0.8 4.00 3.52 2.50 8.00 7.64 11.30 9.93 6.70 ~1.5
M6 1.0 5.00 4.52 3.20 10.00 9.64 14.10 12.53 8.70 ~2.8
M8 1.25 6.50 5.92 4.10 13.00 12.57 18.40 16.34 11.50 ~6.1
M10 1.5 8.00 7.42 5.20 17.00 16.57 24.00 21.54 14.50 ~11.6
M12 1.75 10.00 9.42 6.60 19.00 18.57 26.90 24.02 16.50 ~17.1
M16 2.0 13.00 12.30 8.60 24.00 23.16 33.90 30.11 22.00 ~38.2

* Dimensions per DIN 557. Unit weight values are approximate references for SUS316 material density (7.98 g/cm³). Actual weight may vary slightly by batch. Data is strictly informative.

Selection Guide

Application Scenario Recommended Size Reason
Marine / offshore / boat fittings M5 – M16 A4 SUS316 resists saltwater & chloride corrosion
Chemical processing equipment M8 – M16 Molybdenum content enhances acid resistance
Food & beverage / pharmaceutical M5 – M12 Non-contaminating, easy to clean, hygienic surface
Coastal & outdoor infrastructure M8 – M16 Long-term corrosion resistance in humid salt-air
T-slot / channel framing systems M8 – M12 Square profile locks into slot without rotation
Swimming pools / water treatment M6 – M12 Chlorinated water resistance superior to A2

Standard & Compliance

FULLERKREG DIN 557 A4 chamfered square nuts comply with the following standards:

  • DIN 557 — Chamfered Square Nuts; defines geometry, tolerances, and thread engagement
  • ISO 3506-2 — Mechanical properties of stainless steel nuts (Property Class A4-70)
  • ISO 68-1 — Metric screw thread profile
  • ASTM A276 / AISI 316 — Equivalent material cross-reference for North American markets
  • RoHS Directive — Restriction of Hazardous Substances compliant

Material & Surface

  • Material: Austenitic Marine Stainless Steel SUS316 / AISI 316 / EN 1.4401 (A4)
  • Key Alloying Element: 2–3% Molybdenum (Mo) — significantly enhances pitting and crevice corrosion resistance vs. A2/SUS304
  • Surface: Pickled & Passivated — bright, oxide-free finish that maximizes the natural chromium oxide passive layer
  • Tensile Strength: ≥ 700 MPa (A4-70)
  • Proof Load Stress: Per ISO 3506-2 Annex F
  • A4 vs A2: A4 (SUS316) contains molybdenum, providing significantly better resistance to chlorides, acids, and marine environments compared to A2 (SUS304)

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Why FULLERKREG

  • 🏭 Direct Manufacturer — Factory-direct pricing with full traceability from raw material to finished fastener
  • 📐 Precision Conformance — Strict dimensional inspection per DIN 557; CMM-verified critical dimensions
  • 🔬 Material Certification — Mill test reports (MTR), RoHS & material composition certificates available on request
  • 📦 Flexible MOQ — Bulk pallet quantities or sample packs; custom packaging available
  • 🌍 Global Shipping — Export experience to 50+ countries; sea, air, and express logistics supported
  • ⚡ Fast Lead Time — In-stock standard sizes ship within 3–5 business days
  • 🤝 B2B Wholesale — Volume pricing tiers, OEM labeling, and long-term supply agreements available

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