Grade 12.9 high-strength hex socket screws feature UNF fine threads and a concave end, available in key sizes 5/16-24, 3/8-24, 1/2-20, and 5/8-18. Crafted from heat-treated alloy steel, they deliver exceptional tensile strength (≥1200MPa) and shear resistance, tailored for heavy-duty industrial, mechanical, and precision fastening applications. The UNF fine thread design ensures superior load-bearing capacity and tight engagement, while the concave end provides stable contact with workpieces to prevent slipping during installation. Equipped with a hex socket drive for precise torque control in confined spaces, these screws meet strict industrial standards, making them ideal for high-stress assemblies, machinery, and equipment requiring reliable, long-lasting performance.
Core Features & Advantages
12.9 Grade Ultra-High Strength: Heat-treated alloy steel construction outperforms standard grades, offering excellent durability and load resistance for heavy-duty industrial use.
UNF Fine Thread Precision: 美制统一细牙螺纹（UNF） ensures tight, stable engagement, even load distribution, and enhanced vibration resistance in critical assemblies.
Hex Socket & Concave End: Hex socket enables professional torque application with standard tools; concave end provides secure workpiece contact, avoiding installation slippage.
Multiple UNF Sizes: Covers 5/16-24, 3/8-24, 1/2-20, 5/8-18 sizes, adapting to diverse heavy-duty fastening needs across industries.
Industrial-Grade Reliability: High-precision manufacturing ensures consistent dimensional accuracy and compatibility with global industrial components.
