Home » DIN 557 Metric Square Nut - Class 4.8 - Zinc Plated

DIN 557 Metric Square Nut - Class 4.8 - Zinc Plated

DIN 557 Metric Square Nuts — Class 4.8 · Zinc Plated (Cr3)

FULLERKREG DIN 557 metric square nuts in Class 4.8 are manufactured from Q195 low carbon steel and finished with a trivalent chromium zinc plating (Zinc Cr3) for reliable corrosion protection in general-purpose indoor and light outdoor applications. The chamfered top face ensures clean seating and easy wrench engagement. Cost-effective, RoHS-compliant, and available in bulk wholesale quantities from M5 to M16.

Product Specifications

Property Details
Standard DIN 557
Type Chamfered Square Nut
Property Class 4.8
Material Q195 Low Carbon Steel
Surface Treatment Zinc Plated — Trivalent Chromium (Cr3 / RoHS Compliant)
Zinc Coating Thickness 5–12 μm (typical)
Thread Type Metric Coarse Thread (ISO 68-1)
Size Range M5 – M16
RoHS Compliant Yes — Cr3 (Trivalent Chromium), Hexavalent Chromium (Cr6) Free
Salt Spray Resistance ≥72 hours (per ISO 9227, white rust)

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 ~1.4
M6 1.0 5.00 4.52 3.20 10.00 9.64 14.10 12.53 8.70 ~2.7
M8 1.25 6.50 5.92 4.10 13.00 12.57 18.40 16.34 11.50 ~5.8
M10 1.5 8.00 7.42 5.20 17.00 16.57 24.00 21.54 14.50 ~11.2
M12 1.75 10.00 9.42 6.60 19.00 18.57 26.90 24.02 16.50 ~16.6
M16 2.0 13.00 12.30 8.60 24.00 23.16 33.90 30.11 22.00 ~37.2

* Dimensions per DIN 557. Unit weight values are approximate references for Q195 carbon steel density (7.85 g/cm³), excluding zinc coating. Actual weight may vary slightly by batch. Data is strictly informative.

Selection Guide

Application Scenario Recommended Size Reason
General mechanical assemblies (indoor) M5 – M16 Cost-effective Class 4.8 strength for standard loads
Furniture & woodworking fixtures M5 – M10 Square profile prevents rotation in pre-cut slots
Light structural steel fabrication M8 – M16 Wide bearing surface distributes clamping load
T-slot / aluminum profile framing M5 – M12 Square body locks into extrusion channel without spinning
Electrical enclosures & panel boards M5 – M8 Compact size, RoHS-compliant Cr3 zinc finish
Agricultural & construction equipment M10 – M16 High clamping force, economical carbon steel cost

Standard & Compliance

FULLERKREG DIN 557 Class 4.8 zinc-plated square nuts comply with the following standards:

  • DIN 557 — Chamfered Square Nuts; defines geometry, tolerances, and thread engagement requirements
  • ISO 4034 — Hexagon nuts, style 1 (cross-reference for property class definitions)
  • ISO 898-2 — Mechanical properties of nuts — Property Class 4.8
  • ISO 68-1 — Metric screw thread profile
  • ISO 9227 — Salt spray corrosion test standard
  • RoHS Directive 2011/65/EU — Trivalent Cr3 zinc plating; Hexavalent Chromium (Cr6) free
  • REACH Regulation — No substances of very high concern (SVHC) above threshold

Material & Surface

  • Material: Q195 Low Carbon Steel — Carbon content ≤0.12%, excellent cold formability and weldability
  • Property Class: 4.8 — Proof load stress 380 MPa; Tensile strength ≥ 420 MPa
  • Surface: Zinc Plated with Trivalent Chromium Passivation (Cr3) — bright silver finish
  • Coating Thickness: 5–12 μm zinc layer (electroplated)
  • Corrosion Resistance: ≥72 hours white rust resistance per ISO 9227 salt spray test
  • Environmental: Cr3 passivation is RoHS-compliant and free of hexavalent chromium (Cr6), meeting EU and international environmental regulations
  • Appearance: Bright silver-white metallic finish; uniform coating across all surfaces including thread flanks

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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; thread gauged 100% Go/No-Go
  • 🔬 Material & Coating Certification — Mill test reports (MTR), RoHS & salt spray test certificates available on request
  • 📦 Flexible MOQ — Bulk bag, box, or pallet quantities; custom packaging and labeling 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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