Standard: ASME B 18.31
Available sizes: 1/2 to 9/16 (7 sizes)
| Size | P | e | r | k_max | k_min | s_max | s_min | ds_max | ds_min | k_nominal |
|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 1.0000 | 1.0000 | 3.000 | 0.250 | 0.167 | 1.500 | 1.438 | 2.250 | 2.500 | 1.562 |
| 1/4 | 0.3125 | 0.3125 | 1.625 | 0.111 | 0.083 | 0.469 | 0.440 | 0.875 | 1.125 |
| 0.498 |
| 3/8 | 0.5625 | 0.5625 | 2.125 | 0.167 | 0.111 | 0.844 | 0.802 | 1.375 | 1.625 | 0.896 |
| 5/16 | 0.4375 | 0.4375 | 1.875 | 0.143 | 0.100 | 0.656 | 0.620 | 1.125 | 1.375 | 0.692 |
| 5/8 | 1.3750 | 1.3750 | 3.750 | 0.333 | 0.167 | 2.063 | 2.000 | 3.000 | 3.250 | 2.125 |
| 7/16 | 0.7500 | 0.7500 | 2.500 | 0.200 | 0.125 | 1.125 | 1.075 | 1.750 | 2.000 | 1.175 |
| 9/16 | 1.2500 | 1.2500 | 3.500 | 0.286 | 0.167 | 1.875 | 1.813 | 2.750 | 3.000 | 1.938 |
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.