Standard: GB /T 4388 - 2008
Available sizes: 3.2 to 7 (6 sizes)
| Size | P | s_max | s_min | k_nominal |
|---|---|---|---|---|
| 3.2 | 4 | 5.5 | 3.5 | 55 |
| 4 | 5.5 | 6.3 | 4.2 | 70 |
| 5 | 7 | 7 | 5 | 80 |
| 5.5 | 9 | 8.5 | 5.5 | 100 |
| 6 | 11 | 9.5 | 6.5 | 115 |
| 7 | 13 | 11 | 7 | 135 |
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.
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