Standard: ANSI B 18.21
Available sizes: 10# to 8# (7 sizes)
| Size | P | k_max | k_min | s_max | s_min | k_nominal |
|---|---|---|---|---|---|---|
| 10# | 0.512 | 0.176 | 0.123 | 0.502 | 0.879 | 0.151 |
| 2# | 0.107 | 0.047 | 0.033 | 0.101 | 0.209 | 0.031 |
| 3# | 0.133 | 0.055 | 0.038 | 0.127 | 0.252 | 0.040 |
| 4# | 0.174 | 0.062 | 0.043 | 0.167 |
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.
| 0.307 |
| 0.047 |
| 5# | 0.227 | 0.077 | 0.054 | 0.220 | 0.391 | 0.063 |
| 6# | 0.322 | 0.130 | 0.091 | 0.314 | 0.593 | 0.097 |
| 8# | 0.450 | 0.160 | 0.112 | 0.440 | 0.784 | 0.133 |
© 2026 Ningbo Ruixi Metal Surface Technology Co., Ltd.. All rights reserved.