Standard: GB 921 - 1986
Available sizes: 15 to 30 (7 sizes)
| Size | P | s_max | s_min | k_nominal |
|---|---|---|---|---|
| 15 | 0.7 | 2 | 9、10 | 0.17 |
| 17 | 0.8 | 3 | 14 | 0.3 |
| 20 | 0.8 | 3 | 17、18 | 0.35 |
| 23 | 0.8 | 3 | 22 | 0.42 |
| 25 | 1 | 6 | 28 | 0.79 |
| 27 | 1 | 6 | 32 | 0.9 |
| 30 |
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.
| 1.4 |
| 6 |
| 40 |
| 2.16 |
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.