Standard: NF E 25
Available sizes: 2.5 to 4 (4 sizes)
| Size | P | r | k_max | k_min | s_max | s_min | ds_max | ds_min | k_nominal | ds_nominal |
|---|---|---|---|---|---|---|---|---|---|---|
| 2.5 | 4.2 | 10 | 2.6 | 1.5 | 3.7 | 1.5 | 2.6 | 10.2 | 3 | 3 |
| 3 | 5 | 13 | 3.5 | 1.75 | 4.5 | 1.75 | 3.4 | 13.3 | 4 | 4 |
Standard corrosion protection for indoor and mild outdoor environments.
Salt spray: 96–200 hours | RoHS compliant (trivalent chromium)
High-performance coating for automotive, marine, and harsh environments.
Salt spray: 720–1500 hours | Recommended for grade 8.8+
Heavy-duty protection for structural and outdoor applications.
Salt spray: 500–1000 hours | Thread tolerance adjustment required
Note for high-strength fasteners (Grade 10.9, 12.9): Electroplating processes require hydrogen embrittlement relief baking (minimum 4 hours at 200°C within 4 hours of plating). Contact our engineering team for grade-specific plating recommendations.
Request detailed technical specifications, material certifications, and availability information for your application requirements. Our engineering team can provide product recommendations, custom specifications, and technical documentation.
| 3.5 | 7 | 17 | 4.5 | 2 | 6 | 2 | 4.3 | 17.4 | 5 | 5 |
| 4 | 7.8 | 20 | 5.5 | 2.5 | 7.4 | 2.9 | 5.3 | 20.4 | 6 | 6 |
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.