Home » DIN 9021 Fender Washers (Large OD) — Low Carbon Steel, Zinc CR3 (RoHS)

DIN 9021 Fender Washers (Large OD) — Low Carbon Steel, Zinc CR3 (RoHS)

DIN 9021 Fender Washers (Large OD) — Low Carbon Steel, Zinc CR3 (RoHS)

FULLERKREG DIN 9021 Zinc CR3 fender washers are manufactured from low carbon steel with a Zinc CR3 (trivalent chromium passivation, RoHS compliant) electroplated surface finish. DIN 9021 specifies a large outer diameter washer — the outer diameter (d2) is approximately 3× the bolt nominal diameter — providing a significantly larger bearing area than standard DIN 125A washers to prevent pull-through and embedment in soft or thin materials such as timber, plastic, plywood, thin sheet metal, and composite panels.

The Zinc CR3 surface provides a bright silver appearance with ≥ 240 hours salt spray resistance (ISO 9227) and full RoHS compliance (no hexavalent chromium Cr6+), making these large-OD washers the cost-effective choice for general construction, automotive, and outdoor industrial applications where both large bearing area and corrosion protection are required.

Product Specifications

Standard DIN 9021 (Large OD flat washer, outer diameter ≈ 3× bolt diameter)
Type Large outer diameter (fender / penny) washer — plain flat, no chamfer
Material Low Carbon Steel (mild steel)
Surface Finish Zinc CR3 — electroplated zinc with trivalent chromium passivation (RoHS compliant)
Zinc Coating Thickness 5 – 8 μm (electroplated)
Salt Spray Resistance ≥ 240 hours to red rust (per ISO 9227)
RoHS Compliance Yes — CR3 trivalent chromium, no Cr6+ hexavalent chromium
Size Range M5 – M24
OD Ratio Outer diameter ≈ 3× nominal bolt diameter (vs ~2× for DIN 125A)
Recommended Bolt Grade Grade 4.6, 4.8, 5.6, 6.8 (low to medium strength bolts)
Corrosion Resistance Good — suitable for general indoor, outdoor, and mildly corrosive environments
Magnetic Yes
Related Standard ISO 7093 (large washer series)  |  DIN 125A Zinc CR3 (standard OD)

Product Gallery

[Product Photo 1] [Product Photo 2] [Product Photo 3] [Product Photo 4]

Dimensions — DIN 9021

All dimensions in millimeters (mm). Data per DIN 9021 standard. Zinc CR3 coating (5–8 μm) adds negligible dimensional change.

Nominal Size (Bolt d) d1 — Inner Ø (mm) d2 — Outer Ø (mm) h — Thickness (mm) Weight (kg / 1000 pcs)
M5 5.5 15 1.0 0.71
M6 6.4 18 1.6 1.93
M8 8.4 24 2.0 4.29
M10 10.5 30 2.5 8.29
M12 13.0 37 3.0 14.8
M14 15.0 44 3.0 20.7
M16 17.0 50 3.0 26.7
M20 21.0 60 4.0 52.3
M24 25.0 72 4.0 75.1

* d1 = inner diameter (clearance hole); d2 = outer diameter; h = nominal thickness. All dimensions per DIN 9021. Weights are approximate based on low carbon steel density (7.85 g/cm³). Zinc CR3 coating (5–8 μm) adds negligible weight.

DIN 9021 vs DIN 125A — Large OD vs Standard OD

Property DIN 9021 (This Product) DIN 125A (Standard OD)
Outer diameter ratio ~3× bolt diameter ~2× bolt diameter
M10 outer diameter 30 mm 20 mm
M12 outer diameter 37 mm 24 mm
Bearing area (M12) ~940 mm² ~320 mm² (~3× smaller)
Pull-through resistance High — for timber, plastic, thin sheet Standard — for hard structural materials
ISO equivalent ISO 7093 ISO 7089
Best for Timber, plywood, plastic, thin sheet, composite panels Steel, concrete, hard structural materials

Zinc CR3 vs HDG vs Stainless — Surface Selection Guide

Property Zinc CR3 (This Product) HDG A2 / A4 Stainless
Zinc coating thickness 5 – 8 μm 45 – 85 μm N/A
Salt spray resistance ≥ 240 hours ≥ 1000 hours Excellent
Outdoor service life 3 – 10 years 20 – 50+ years 20–50+ years
RoHS compliant Yes (CR3) Yes Yes
Appearance Bright silver / blue iridescent Matte grey / spangled Silver / whitened
Cost Low Low–medium High
Best for General construction, automotive, short–medium outdoor Long-term outdoor structural, civil engineering Marine, coastal, treated timber, food-grade

Material & Coating Properties

Property Value
Base Material Low Carbon Steel (mild steel, ≤ 0.25% C)
Yield Strength ≥ 235 MPa
Tensile Strength 370 – 500 MPa
Surface Finish Zinc CR3 — electroplated zinc + trivalent chromium passivation
Zinc Coating Thickness 5 – 8 μm
Salt Spray Resistance ≥ 240 hours to red rust (ISO 9227)
RoHS Compliance Yes — CR3 trivalent chromium, no Cr6+
Temperature Limit Up to +120°C (zinc coating service limit)
Magnetic Yes
Density 7.85 g/cm³

Typical Applications

  • 🏗️ General construction & timber framing — large OD prevents bolt pull-through in timber framing, light wood construction, and general building work; Zinc CR3 provides corrosion protection for outdoor exposure
  • 🚗 Automotive & vehicle body — large OD distributes load across thin sheet metal and body panels; Zinc CR3 meets RoHS requirements for automotive supply chains
  • 🧱 Plastic & composite panels — large OD prevents pull-through and deformation in plastic, GRP, and composite panel fastening
  • 📦 Plywood & board materials — large OD distributes load in plywood, OSB, and particle board connections
  • 🏭 Industrial plant & equipment — large OD for thin panel and cladding fastening in indoor and semi-outdoor industrial environments
  • 🏠 Roofing & cladding — large OD distributes clamping load across thin metal sheet and cladding panels; Zinc CR3 for general outdoor exposure
  • 🔧 General MRO — large OD replacement washers for maintenance, repair, and overhaul across construction and manufacturing

Frequently Asked Questions

Q: What is the difference between DIN 9021 Zinc CR3 and DIN 9021 HDG?
A: Both products have identical DIN 9021 dimensions and low carbon steel base material. The difference is the zinc coating: Zinc CR3 is electroplated (5–8 μm, ≥240h salt spray, 3–10 year outdoor life); HDG is hot dip galvanised (45–85 μm, ≥1000h salt spray, 20–50+ year outdoor life). Choose Zinc CR3 for general construction and short-to-medium term outdoor applications; choose HDG for long-term structural outdoor applications requiring 20+ year service life.

Q: What is the difference between DIN 9021 and DIN 125A?
A: DIN 9021 has an outer diameter of approximately 3× the bolt nominal diameter, vs approximately 2× for DIN 125A. For M12: DIN 9021 d2 = 37 mm vs DIN 125A d2 = 24 mm — approximately 3× greater bearing area. DIN 9021 is used where the larger bearing area is needed to prevent pull-through in soft materials (timber, plastic, thin sheet). Both have the same inner diameter for the same bolt size.

Q: What is Zinc CR3 and why is it RoHS compliant?
A: Zinc CR3 refers to electroplated zinc with a trivalent chromium (Cr3+) passivation layer. Traditional zinc plating used hexavalent chromium (Cr6+) passivation, which is toxic and restricted under the EU RoHS Directive and REACH regulations. CR3 trivalent chromium passivation provides equivalent corrosion protection without the environmental and health hazards of Cr6+. FULLERKREG Zinc CR3 washers are fully RoHS compliant.

Q: Can I use DIN 9021 Zinc CR3 washers for outdoor timber construction?
A: Yes, for general outdoor timber applications with a 3–10 year service life expectation. For long-term structural timber (20+ years), specify DIN 9021 HDG washers. For marine, coastal, or ACQ/CCA treated timber applications, specify DIN 9021 A4 stainless steel washers for superior corrosion resistance.

Q: What is the ISO equivalent of DIN 9021?
A: DIN 9021 is equivalent to ISO 7093 (large washer series). Both specify a large outer diameter washer with d2 ≈ 3× bolt diameter. DIN 9021 is the German national standard; ISO 7093 is the international equivalent.

Sorry, this collection is empty.
Continue shopping