Standard: GB /T 305 - 1989
Available sizes: 22 to 37 (7 sizes)
| Standard Body | Standard Number |
|---|---|
| GB | GB /T 305 |
| ISO | ISO 464 |
| Size | P | k_max | k_min | s_max | s_min | k_nominal |
|---|---|---|---|---|---|---|
| 22 | 26.80 | 0.6 | 2 | 22.50 | 22.2 | 0.7 |
| 24 | 32.80 | 0.75 | 3 | 28.30 | 28 | 0.85 |
| 28 | 36.80 | 0.75 | 3 | 32.30 | 32 | 0.85 |
| 30 | 41.80 | 0.75 | 3 | 37.30 |
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.
| 37 |
| 0.85 |
| 32 | 44.80 | 0.75 | 3 | 40.30 | 39.9 | 0.85 |
| 34 | 47.80 | 0.75 | 4 | 43.30 | 42.9 | 0.85 |
| 37 | 54.80 | 0.75 | 4 | 50.30 | 49.9 | 0.85 |
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