S-91251A018 1/2"-20 x 1 3/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi for reliable performance in high-stress applications.
• Superior corrosion resistance provided by the black-oxide finish, extending service life in demanding environments.
• Precise Class 3A thread fit ensures tight, secure fastening with minimal risk of loosening.
• Fine UNF thread design offers improved vibration resistance and better adjustment control.
• Hex socket drive allows for high torque application and easy installation in confined spaces.
• Full threading along the entire length for maximum grip and versatility in various assembly setups.
• Compliance with ASTM A574 guarantees material quality and manufacturing consistency.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address critical industrial challenges, such as vibration-induced loosening and corrosion in harsh conditions. The fine UNF thread (1/2"-20) and Class 3A fit provide superior clamping force and stability, making it ideal for precision machinery, automotive assemblies, and heavy-duty equipment. The hex drive (3/8") facilitates efficient installation with standard tools, reducing assembly time. Its high tensile strength (170,000 psi) and Rockwell C37 hardness ensure durability under extreme loads, while the black-oxide surface treatment enhances resistance to wear and environmental factors, supporting long-term reliability in industrial fasteners applications.

Specification Summary & Compliance

This screw features a 1/2"-20 UNF fine thread with Class 3A tolerance for precise fit, fully threaded design, and meets ASTM A574 specifications. It is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity for global industrial use.