+86 (0) 159 5016 9967
sales@fullerkr.com
FULLERKREG DIN 985 Class 8 nylon insert lock nuts are cold-forged from 10B21 boron alloy steel and finished with Zinc Cr3 (trivalent chromium) electroplating, delivering high-strength prevailing torque performance with reliable corrosion protection. The integrated nylon collar locks against vibration and dynamic loads without damaging the mating thread. Designed for demanding mechanical assemblies where Class 4 carbon steel is insufficient — including automotive powertrains, heavy machinery, structural steel, and high-load industrial equipment.
| 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 8 |
| 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 (Low Carbon Steel) | Class 8 (10B21 Alloy Steel) ✓ This Product |
|---|---|---|
| Material | ML08AL Low Carbon Steel | 10B21 Boron Alloy Steel (Q&T) |
| Proof Load (N/mm²) | 510 | 800 |
| Hardness | 188 HV max | 302 HV max |
| Applicable Bolt Class | 4.8 or lower | 8.8 or lower |
| Heat Treatment | None | Quenched & Tempered |
| Typical Application | General / light-duty assemblies | Automotive, heavy machinery, structural |
| Application Scenario | Recommended Size | Key Consideration |
|---|---|---|
| Automotive powertrain & suspension | M8 – M16 | High-strength, vibration-resistant locking |
| Heavy machinery & construction equipment | M10 – M20 | Class 8 handles high dynamic loads |
| Steel structures & bridges | M12 – M20 | Matches 8.8 bolt assemblies |
| Agricultural & off-road equipment | M8 – M20 | Withstands shock & vibration in field use |
| Industrial pumps & compressors | M6 – M16 | Nylon insert prevents loosening under cyclic load |
| Wind turbine & energy equipment | M12 – M20 | High proof load for critical structural joints |
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 8. 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). Heat treatment (quench & temper) is applied to achieve Class 8 mechanical properties.
DIN 985 Class 8 Zinc Finish Alloy Steel Nylon Insert Lock Nuts – actual product photos:
Q: Why use 10B21 boron alloy steel for Class 8 nuts?
A: 10B21 contains boron (B) which significantly improves hardenability during quench & temper heat treatment, allowing the nut to achieve Class 8 mechanical properties (800 N/mm² proof load) with excellent toughness and consistent hardness throughout the cross-section — at lower cost than traditional alloy steels.
Q: Can Class 8 DIN 985 nylon lock nuts be used with 10.9 bolts?
A: No. Class 8 nuts are rated for use with Class 8.8 bolts or lower. For 10.9 bolt assemblies, a higher-grade nut is required. Using an under-rated nut risks thread stripping under proof load.
Q: What is the risk of hydrogen embrittlement with zinc-plated high-strength nuts?
A: Electroplating can introduce hydrogen into the steel, causing embrittlement in high-strength fasteners. FULLERKREG applies a post-plating baking (de-embrittlement) process where required to eliminate this risk, per ISO 4042 and ASTM F1941 guidelines.
Q: Can DIN 985 Class 8 nylon lock nuts be reused?
A: Limited reuse is possible, but for critical or safety-relevant joints, single-use is strongly recommended. The nylon insert loses prevailing torque effectiveness after repeated cycling, and Class 8 joints are typically in high-load applications where reliability is paramount.
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.
19 Products
20% off all Cordless tool kits.
Fresh picks for your outdoor space, just in.