Standard: UNI 5590
Available sizes: (M3.5) to M5 (7 sizes)
| Standard Body | Standard Number |
|---|---|
| GB | GB /T 6174 |
| IS | IS 1364(-5) |
| DIN | DIN EN ISO 4036 |
| ISO | ISO 4036 |
| UNI | UNI 5590 |
| Size | P | k_max | k_min | s_max | s_min | k_nominal |
|---|---|---|---|---|---|---|
| (M3.5) | 1.25 | 12.73 | 3.2 | 14.38 | 4 | 13 |
| M1.6 | 0.4 | 3.82 | 0.11 | 4.38 | 1.2 | 4 |
| M2 | 0.5 | 5.32 | 0.29 | 5.08 | 1.8 | 5.5 |
| M2.5 | 0.7 | 6.78 | 0.57 | 7.74 |
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.
| 2.2 |
| 7 |
| M3 | 1 | 9.73 | 1.5 | 11.05 | 3.2 | 10 |
| M4 | 1.75 | 18.67 | 10.4 | 21.1 | 6 | 19 |
| M5 | 2 | 21.67 | 15.9 | 24.49 | 7 | 22 |
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.