Standard: ANSI B 18.21
Available sizes: 2# to 8# (6 sizes)
| Size | P | k_max | k_min | s_max | s_min | k_nominal |
|---|---|---|---|---|---|---|
| 2# | 0.109 | 0.016 | 0.01 | 0.102 | 0.232 | 0.215 |
| 3# | 0.136 | 0.02 | 0.014 | 0.129 | 0.28 | 0.255 |
| 4# | 0.176 | 0.023 | 0.018 | 0.168 | 0.34 | 0.325 |
| 5# | 0.231 | 0.027 | 0.02 |
| 0.221 |
| 0.41 |
| 0.394 |
| 6# | 0.332 | 0.034 | 0.028 | 0.32 | 0.61 | 0.594 |
| 8# | 0.398 | 0.04 | 0.032 | 0.384 | 0.692 | 0.67 |
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.