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FULLERKREG DIN 125A flat washers are manufactured from A2 stainless steel (SUS304) with a whitened and passivated surface finish. Conforming to DIN 125A, ISO 7089, and GB/T 97.1, these washers distribute bolt and nut bearing loads over a larger surface area, protect the joint surface from damage during tightening, and provide a clean, corrosion-resistant bearing face for structural, mechanical, and general fastening applications.
The A2 (SUS304) material provides excellent corrosion resistance for outdoor, food-grade, and mildly corrosive environments, making these washers the standard choice for use with A2 stainless steel bolts and nuts (DIN 931 / DIN 933 / DIN 934).
| 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 | A2 Stainless Steel / SUS304 / 1.4301 |
| Surface Finish | Whitened & Passivated |
| Size Range | M3 – M36 |
| Hardness | ≤ 200 HV (per ISO 7089) |
| Corrosion Resistance | Good — suitable for outdoor, food-grade, and mild corrosive environments |
| Magnetic | Slightly magnetic after cold working (stamping) |
| Recommended Pairing | A2 stainless bolts (DIN 931 / DIN 933) and nuts (DIN 934) for full material compatibility |
| Related Standard | ISO 7089 | GB/T 97.1 | DIN 125B (ISO 7090, double chamfer variant) |
| [Product Photo 1] | [Product Photo 2] | [Product Photo 3] | [Product Photo 4] |
All dimensions in millimeters (mm). Data per DIN 125A / ISO 7089 standard. Verified against standard reference data.
| 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 | 0.07 |
| M4 | 4.3 | 9 | 0.8 | 0.19 |
| M5 | 5.3 | 10 | 1.0 | 0.29 |
| M6 | 6.4 | 12 | 1.6 | 0.72 |
| M8 | 8.4 | 16 | 1.6 | 1.28 |
| M10 | 10.5 | 20 | 2.0 | 2.50 |
| M12 | 13.0 | 24 | 2.5 | 5.00 |
| M14 | 15.0 | 28 | 2.5 | 6.80 |
| M16 | 17.0 | 30 | 3.0 | 9.50 |
| M18 | 19.0 | 34 | 3.0 | 12.5 |
| M20 | 21.0 | 37 | 3.0 | 15.0 |
| M22 | 23.0 | 39 | 3.0 | 16.5 |
| M24 | 25.0 | 44 | 4.0 | 29.0 |
| M27 | 28.0 | 50 | 4.0 | 38.0 |
| M30 | 31.0 | 56 | 4.0 | 48.0 |
| M33 | 34.0 | 60 | 5.0 | 68.0 |
| M36 | 37.0 | 66 | 5.0 | 88.0 |
* d1 = inner diameter (clearance hole); d2 = outer diameter; h = nominal thickness. All dimensions per DIN 125A / ISO 7089. Weights are approximate based on A2 stainless steel density (7.93 g/cm³).
| Feature | DIN 125A (This Product) | DIN 125B |
|---|---|---|
| Inner hole chamfer | Chamfer on one side only | Chamfer on both sides (double chamfer) |
| ISO equivalent | ISO 7089 | ISO 7090 |
| Dimensions (d1, d2, h) | Identical to DIN 125B | Identical to DIN 125A |
| Typical use | General fastening — most common type worldwide | Applications requiring chamfer on both bearing faces |
| Stock availability | Standard stock item | Less common |
| Property | Value |
|---|---|
| Material Designation | A2 / SUS304 / 1.4301 / 0Cr18Ni9 |
| Chromium Content | 17.5 – 19.5% |
| Nickel Content | 8.0 – 10.5% |
| Tensile Strength | ≥ 500 MPa (annealed) |
| Hardness | ≤ 200 HV (per ISO 7089) |
| Surface Finish | Whitened & Passivated |
| Corrosion Resistance | Good — suitable for outdoor, food-grade, and mild chemical environments |
| Temperature Range | −50°C to +300°C (continuous service) |
| Magnetic | Slightly magnetic after cold working (stamping process) |
| Density | 7.93 g/cm³ |
| Manufacturing Process | Cold stamped from A2 stainless steel strip |
Q: What is the difference between DIN 125A and ISO 7089?
A: DIN 125A and ISO 7089 are equivalent standards specifying the same flat washer geometry and dimensions. 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. FULLERKREG washers conform to all three standards.
Q: What bolt sizes do these washers fit?
A: Each washer is sized by nominal bolt diameter. The inner diameter (d1) is slightly larger than the bolt shank to provide a clearance fit. For example, an M10 washer has d1 = 10.5 mm (clearance for M10 bolt shank, nominal 10 mm) and d2 = 20 mm outer diameter. Always match the washer nominal size to the bolt nominal size.
Q: Should I use washers under both the bolt head and the nut?
A: For most structural and mechanical applications, washers should be used under both the bolt head and the nut to distribute clamping load evenly and protect both joint surfaces from damage during tightening. For non-critical applications, a washer under the rotating element (usually the nut) is the minimum recommendation.
Q: Are A2 stainless washers suitable for outdoor use?
A: Yes. A2 (SUS304) stainless steel provides good corrosion resistance for general outdoor, coastal, and mildly corrosive environments. For marine, offshore, or high-chloride environments where superior pitting and crevice corrosion resistance is required, specify A4 (SUS316) stainless washers instead.
Q: Can I use A2 stainless washers with carbon steel bolts?
A: A2 stainless washers can be used with carbon steel bolts in dry or non-corrosive environments. However, in wet or corrosive environments, the galvanic potential difference between stainless steel and carbon steel can accelerate corrosion of the carbon steel. For best results and full corrosion protection, use matching A2 stainless bolts, nuts, and washers throughout the fastener assembly.
Q: Why are A2 stainless washers slightly magnetic?
A: A2 (SUS304) stainless steel is an austenitic grade that is non-magnetic in its annealed state. However, the cold stamping process used to manufacture washers induces a small amount of strain-induced martensite, making the finished washers slightly magnetic. This is normal and does not affect corrosion resistance or mechanical performance.
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