Standard: QC /T 344 - 1999
Available sizes: 20 to 32 (8 sizes)
| Size | P | k_max | k_min | s_max | s_min | k_nominal | ds_nominal |
|---|---|---|---|---|---|---|---|
| 20 | 23.5 | 0.9 | 2.5 | 23.65 | 23.35 | 1 | 8 |
| 22 | 26.9 | 0.9 | 2.5 | 27.05 | 26.75 | 1 | 8 |
| 24 | 30.1 | 1 | 3.2 | 30.3 | 29.9 | 1.1 | 8 |
| 25 |
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.
| 34.4 |
| 1 |
| 3.2 |
| 34.6 |
| 34.2 |
| 1.1 |
| 8 |
| 26 | 37.8 | 1 | 3.2 | 38 | 37.6 | 1.1 | 10 |
| 28 | 39.8 | 1 | 3.2 | 40 | 39.6 | 1.1 | 10 |
| 30 | 43.5 | 1 | 3.2 | 43.7 | 43.3 | 1.1 | 12 |
| 32 | 45.5 | 1 | 3.2 | 45.7 | 45.3 | 1.1 | 12 |
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