Standard: UNI 5739 - 1965
Available sizes: M3 to M8 (6 sizes)
| Standard Body | Standard Number |
|---|---|
| EN | EN 24017 |
| GB | GB /T 5783 |
| IS | IS 1364(-2) |
| NF | NF E 25-114 |
| DIN | DIN EN ISO 4017 |
| ISO | ISO 4017 |
| UNI | UNI 5739 |
| ANSI | ANSI/ASME B 18.2.3.1M |
| Size | P | k_max | k_min | s_max | s_min | k_nominal |
|---|---|---|---|---|---|---|
| M3 | 0.7 | 7 | 6.85 | 2.8 | 2.925 | 2.675 |
| M4 | 1 | 10 | 9.78 | 4 | 4.15 | 3.85 |
| M5 | 1.25 | 13 | 12.73 | 5.5 | 5.65 | 5.35 |
| M6 | 1.75 | 19 | 18.67 | 8 |
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.
| 8.18 |
| 7.82 |
| M7 | 2 | 24 | 23.67 | 10 | 10.18 | 9.82 |
| M8 | 2.5 | 30 | 29.67 | 13 | 13.215 | 12.785 |
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.