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FULLERKREG DIN 125A 140HV Zinc CR3 flat washers are manufactured from carbon steel Q235 (mild steel, equivalent to S235 / A36) with a Zinc CR3 (trivalent chromium passivation, RoHS compliant) electroplated surface finish. Conforming to DIN 125A, ISO 7089, and GB/T 97.1, these are the most widely used general-purpose flat washers in construction, manufacturing, and industrial assembly — combining the cost-effectiveness of mild steel with the corrosion protection of zinc electroplating and the environmental compliance of CR3 trivalent chromium passivation.
The Zinc CR3 surface provides a bright silver appearance with ≥ 240 hours salt spray resistance (ISO 9227), making these washers suitable for general indoor, outdoor, and mildly corrosive environments. The CR3 trivalent chromium passivation is fully RoHS compliant — no hexavalent chromium (Cr6+).
Note: 140HV soft washers are suitable for use with Grade 4.6, 4.8, 5.6, and 6.8 bolts. For Grade 8.8, 10.9, or 12.9 high-tensile bolts, specify FULLERKREG 300HV hardened washers to prevent embedding and preload loss.
| Standard | DIN 125A ≡ ISO 7089 ≡ GB/T 97.1 |
| Type | Plain flat washer — normal series (Form A), chamfer on one side of inner hole |
| Material | Carbon Steel Q235 (S235 / A36 / mild steel) |
| Heat Treatment | None — as-stamped (cold formed) |
| Hardness | ~140 HV (typical for Q235 mild steel; ≤ 200 HV per ISO 7089 normal grade) |
| 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 | M3 – M36 |
| 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 7089 (normal washer, 200 HV grade) | GB/T 97.1 | DIN 125B (ISO 7090, double chamfer) |
| [Product Photo 1] | [Product Photo 2] | [Product Photo 3] | [Product Photo 4] |
All dimensions in millimeters (mm). Data per DIN 125A / ISO 7089 standard.
| Nominal Size (Bolt d) | d1 — Inner Ø (mm) | d2 — Outer Ø (mm) | h — Thickness (mm) | Weight (kg / 1000 pcs) |
|---|---|---|---|---|
| M3 | 3.2 | 7 | 0.5 | 0.06 |
| M4 | 4.3 | 9 | 0.8 | 0.18 |
| M5 | 5.3 | 10 | 1.0 | 0.27 |
| M6 | 6.4 | 12 | 1.6 | 0.68 |
| M8 | 8.4 | 16 | 1.6 | 1.21 |
| M10 | 10.5 | 20 | 2.0 | 2.37 |
| M12 | 13.0 | 24 | 2.5 | 4.73 |
| M14 | 15.0 | 28 | 2.5 | 6.43 |
| M16 | 17.0 | 30 | 3.0 | 8.98 |
| M18 | 19.0 | 34 | 3.0 | 11.8 |
| M20 | 21.0 | 37 | 3.0 | 14.2 |
| M22 | 23.0 | 39 | 3.0 | 15.6 |
| M24 | 25.0 | 44 | 4.0 | 27.4 |
| M27 | 28.0 | 50 | 4.0 | 35.9 |
| M30 | 31.0 | 56 | 4.0 | 45.4 |
| M33 | 34.0 | 60 | 5.0 | 64.3 |
| M36 | 37.0 | 66 | 5.0 | 83.2 |
* d1 = inner diameter (clearance hole); d2 = outer diameter; h = nominal thickness. All dimensions per DIN 125A / ISO 7089. Weights are approximate based on carbon steel density (7.85 g/cm³). Zinc CR3 coating (5–8 μm) adds negligible weight.
| Property | Zinc CR3 (This Product) | Black Oxide |
|---|---|---|
| Process | Electroplated zinc + trivalent chromium passivation | Alkaline blackening (conversion coating) |
| Coating thickness | 5 – 8 μm | 1 – 2 μm |
| Salt spray resistance | ≥ 240 hours to red rust | ≤ 24 hours (oil-wetted) |
| Corrosion protection | Good — cathodic zinc protection | Minimal — oil-dependent |
| RoHS compliance | Yes (CR3 trivalent) | Yes |
| Appearance | Bright silver / light blue iridescent | Matte black |
| Outdoor suitability | Good — general industrial & mild outdoor | Poor — indoor / oil-wetted only |
| Best for | General construction, outdoor, automotive | Indoor machinery, precision equipment |
| Bolt Property Class | Recommended Washer Grade | Washer Hardness | FULLERKREG Product |
|---|---|---|---|
| 4.6 / 4.8 / 5.6 / 6.8 | Normal (≤ 200 HV) | ~140 HV Q235 | This product — DIN 125A 140HV Zinc CR3 |
| 8.8 | Normal or Hardened (300 HV recommended) | 300 – 370 HV | DIN 125A 300HV Zinc CR3 / Black |
| 10.9 | Hardened (300 HV minimum) | 300 – 370 HV | DIN 125A 300HV Zinc CR3 / Black |
| 12.9 | Hardened (300 HV minimum) | 300 – 370 HV | DIN 125A 300HV Zinc CR3 / Black |
| A2-70 / A4-70 (stainless) | A2 / A4 stainless (≤ 200 HV) | ≤ 200 HV | DIN 125A A2 / A4 Stainless |
| Property | Value |
|---|---|
| Base Material | Carbon Steel Q235 (S235 / A36 / mild steel) |
| Carbon Content | ≤ 0.22% (low carbon, mild steel) |
| Yield Strength | ≥ 235 MPa |
| Tensile Strength | 370 – 500 MPa |
| Heat Treatment | None — as-stamped (cold formed) |
| Hardness | ~140 HV (typical; ≤ 200 HV per ISO 7089 normal grade) |
| 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 |
| Weldability | Excellent (low carbon content) |
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 and suitable for automotive, electronics, and EU-market supply chains.
Q: Can I use 140HV Zinc CR3 washers outdoors?
A: Yes. The Zinc CR3 coating provides ≥ 240 hours salt spray resistance (ISO 9227), making these washers suitable for general outdoor and mildly corrosive environments. For long-term outdoor structural applications, coastal environments, or applications requiring 20+ year service life, consider hot dip galvanised (HDG) washers with 45–85 μm zinc coating for superior long-term corrosion protection.
Q: What is Q235 carbon steel?
A: Q235 is a Chinese national standard (GB/T 700) designation for a low-carbon mild steel with a minimum yield strength of 235 MPa, equivalent to S235 (EN 10025) and approximately ASTM A36. It is the most widely used structural steel in China and is ideal for stamped flat washers due to its excellent formability, weldability, and low cost.
Q: What is the difference between 140HV Zinc CR3 and 300HV Zinc CR3 washers?
A: Both products have identical DIN 125A dimensions and Zinc CR3 surface finish. The key difference is hardness and base material: 140HV uses Q235 mild steel (as-stamped, no heat treatment) suitable for Grade 4.6–6.8 low-strength bolts; 300HV uses carbon steel 45# with quench and temper heat treatment, suitable for Grade 8.8/10.9/12.9 high-tensile bolts. Always match the washer hardness grade to the bolt property class.
Q: What is the difference between DIN 125A and ISO 7089?
A: DIN 125A and ISO 7089 are equivalent standards with identical dimensions. ISO 7089 additionally defines two hardness grades: 200 HV (normal — this product falls within this grade at ~140 HV) and 300 HV (hardened). DIN 125A is the German national standard; ISO 7089 is the international equivalent. GB/T 97.1 is the Chinese national standard with the same dimensions.
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