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FULLERKREG DIN 985 Class 10 nylon insert lock nuts represent the highest strength grade in the DIN 985 nylon insert lock nut series. Cold-forged from 10B21 boron alloy steel with full quench-and-temper heat treatment, and finished with Zinc Cr3 (trivalent chromium) electroplating, these nuts deliver exceptional proof load capacity combined with reliable vibration-resistant locking. The integrated nylon collar provides prevailing torque that resists loosening under the most demanding dynamic and shock loads — without damaging the mating thread. Designed for critical high-strength assemblies paired with Class 10.9 bolts in automotive, heavy-duty industrial, and structural engineering applications.
| Attribute | Details |
|---|---|
| Standard | DIN 985 / ISO 7042 |
| Type | Hexagon Nylon Insert Lock Nut (Prevailing Torque) |
| Material | 10B21 Boron Alloy Steel (quenched & tempered) |
| Strength Class | Class 10 |
| Surface Finish | Zinc Cr3 (Trivalent Chromium Electroplating) |
| Zinc Layer Thickness | ≥ 5 μm (standard); ≥ 8 μm available on request |
| Thread | Metric Coarse Thread (ISO 68-1) |
| Size Range | M3 – M20 |
| Insert Material | Nylon (Polyamide PA66) |
| Temperature Range | -40°C to +120°C |
| Heat Treatment | Quenched & Tempered (Q&T) |
| RoHS Compliant | Yes (Cr3 / Trivalent — no hexavalent chromium) |
| Brand | FULLERKREG |
All dimensions in millimeters (mm). Unit weight (单重) is approximate reference value.
| Nominal Size | Pitch (mm) | F – Width Across Flats Max (mm) | F – Width Across Flats Min (mm) | G – Width Across Corners Min (mm) | H – Thickness Max (mm) | H – Thickness Min (mm) | I – Wrenching Height Min (mm) | 单重 (g/pc) |
|---|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.50 | 5.32 | 6.01 | 4.0 | 3.7 | 2.4 | ~0.6 |
| M4 | 0.7 | 7.00 | 6.78 | 7.66 | 5.0 | 4.7 | 2.9 | ~1.2 |
| M5 | 0.8 | 8.00 | 7.78 | 8.79 | 5.0 | 4.7 | 3.2 | ~2.0 |
| M6 | 1.0 | 10.00 | 9.78 | 11.05 | 6.0 | 5.7 | 4.0 | ~3.5 |
| M7 | 1.0 | 11.00 | 10.73 | 12.12 | 7.5 | 7.14 | 4.7 | ~5.5 |
| M8 | 1.25 | 13.00 | 12.73 | 14.38 | 8.0 | 7.64 | 5.6 | ~7.5 |
| M10 | 1.5 | 17.00 | 16.73 | 18.90 | 10.0 | 9.64 | 6.5 | ~14 |
| M12 | 1.75 | 19.00 | 18.67 | 21.10 | 12.0 | 11.57 | 8.0 | ~23 |
| M14 | 2.0 | 22.00 | 21.67 | 24.49 | 14.0 | 13.3 | 9.5 | ~37 |
| M16 | 2.0 | 24.00 | 23.67 | 26.75 | 16.0 | 15.3 | 10.5 | ~55 |
| M18 | 2.5 | 27.00 | 26.16 | 29.56 | 18.0 | 17.66 | 13.0 | ~78 |
| M20 | 2.5 | 30.00 | 29.16 | 32.95 | 20.0 | 19.7 | 14.0 | ~110 |
* Dimensions per DIN 985 / ISO 7042. Unit weight values are approximate and for reference only. Alloy steel density ≈ 7.85 g/cm³. Actual weight may vary slightly by batch.
| Property | Class 4 | Class 8 | Class 10 ✓ This Product |
|---|---|---|---|
| Material | ML08AL Low Carbon Steel | 10B21 Alloy Steel (Q&T) | 10B21 Alloy Steel (Q&T) |
| Proof Load (N/mm²) | 510 | 800 | 1040 |
| Hardness (HV max) | 188 | 302 | 353 |
| Applicable Bolt Class | 4.8 or lower | 8.8 or lower | 10.9 or lower |
| Heat Treatment | None | Q&T | Q&T (higher temper) |
| Typical Application | General / light-duty | Automotive, machinery | Critical high-load, 10.9 bolt assemblies |
| Application Scenario | Recommended Size | Key Consideration |
|---|---|---|
| Automotive engine & drivetrain (10.9 bolts) | M8 – M16 | Only Class 10 nut matches 10.9 bolt proof load |
| Heavy construction & mining equipment | M12 – M20 | Extreme shock & vibration resistance required |
| Crane & lifting equipment | M12 – M20 | Safety-critical joints demand highest nut grade |
| Rail & transportation structures | M10 – M20 | High fatigue & vibration environment |
| Wind turbine tower & nacelle | M16 – M20 | 1040 N/mm² proof load for structural integrity |
| Hydraulic & pneumatic systems | M8 – M16 | Nylon insert prevents loosening under pressure cycles |
These nylon insert lock nuts are manufactured in full compliance with DIN 985 and the equivalent international standard ISO 7042. Mechanical properties conform to ISO 898-2 Class 10. Surface treatment meets ISO 4042 (electroplated zinc coatings) with trivalent chromate passivation (Cr3), fully compliant with RoHS 2011/65/EU and ELV 2000/53/EC — no hexavalent chromium (Cr6). Full quench-and-temper heat treatment is applied to achieve Class 10 mechanical properties, with post-plating baking to eliminate hydrogen embrittlement risk.
DIN 985 Class 10 Zinc Finish Alloy Steel Nylon Insert Lock Nuts – actual product photos:
Q: What is the difference between Class 8 and Class 10 DIN 985 nylon lock nuts?
A: Class 10 has a significantly higher proof load (1040 N/mm² vs 800 N/mm² for Class 8) and higher hardness (353 HV vs 302 HV). Class 10 is specifically required when pairing with Class 10.9 bolts — using a Class 8 nut with a 10.9 bolt risks thread stripping under full proof load.
Q: Can Class 10 DIN 985 nylon lock nuts be used with 12.9 bolts?
A: No. Class 10 nuts are rated for Class 10.9 bolts or lower. For 12.9 bolt assemblies, a Class 12 nut is required. Using an under-rated nut in a 12.9 assembly is a safety risk and not recommended.
Q: Why is post-plating baking important for Class 10 nuts?
A: High-strength fasteners (Class 10 and above) are susceptible to hydrogen embrittlement during electroplating. Post-plating baking (typically 200°C for 4+ hours) drives out absorbed hydrogen, restoring ductility and preventing delayed brittle fracture. FULLERKREG applies this process as standard for all Class 10 zinc-plated products.
Q: Can DIN 985 Class 10 nylon lock nuts be reused?
A: Reuse is not recommended for Class 10 applications. These nuts are typically used in safety-critical, high-load joints where the nylon insert’s prevailing torque must be fully reliable. Single-use is strongly advised.
Q: Do you provide material test certificates and mechanical test reports?
A: Yes. Mill test certificates (MTC), hardness test reports, salt spray test reports (ISO 9227), and RoHS declarations are available upon request for all orders.
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