Standard: GB /T 77 - 2007
Available sizes: M1.6 to M6 (7 sizes)
| Standard Body | Standard Number |
|---|---|
| GB | GB /T 77 |
| DIN | DIN EN ISO 4026 |
| ISO | ISO 4026 |
| UNI | UNI 5923 |
| Size | P | r | k_max | k_min | s_max | s_min | ds_max | ds_min | k_nominal | ds_nominal |
|---|---|---|---|---|---|---|---|---|---|---|
| M1.6 | 0.4 | 3 |
| 0.9 |
| 0.913 |
| 1.00 |
| 0.75 |
| 0.8 |
| 1.7 |
| 1.011 |
| 0.887 |
| M2 | 0.5 | 3 | 1.5 | 1.58 | 2.00 | 1.75 | 1.2 | 2 | 1.733 | 1.52 |
| M2.5 | 0.8 | 5 | 2.5 | 2.58 | 3.5 | 3.2 | 2 | 3 | 2.873 | 2.52 |
| M3 | 1.25 | 8 | 4 | 4.095 | 5.5 | 5.2 | 3 | 5 | 4.583 | 4.02 |
| M4 | 1.75 | 12 | 6 | 6.14 | 8.50 | 8.14 | 4.8 | 8 | 6.863 | 6.02 |
| M5 | 2.5 | 20 | 10 | 10.175 | 15.00 | 14.57 | 8 | 12 | 11.429 | 10.025 |
| M6 | 3 | 25 | 12 | 12.212 | 18.00 | 17.57 | 10 | 15 | 13.716 | 12.032 |
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.
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.