S-91251A577 5/16"-18 x 5/16" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
• Class 3A thread fit provides superior precision and tighter tolerances for secure, vibration-resistant assemblies in demanding environments.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable finish, extending service life in harsh conditions.
• Fully threaded design allows for maximum grip and uniform load distribution along the entire length, improving joint integrity.
• Hex socket drive (1/4") enables easy installation with standard tools, minimizing stripping and ensuring efficient assembly in confined spaces.
• Coarse UNC threads facilitate quick engagement and disassembly, saving time in maintenance and repair operations.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety, meeting global regulatory standards for industrial use.

Professional Applications & Engineering Value

This 5/16"-18 UNC Socket Head Cap Screw is engineered to address critical challenges in industrial settings, such as vibration loosening and material fatigue. The black-oxide alloy steel construction, combined with a Rockwell C37 hardness, provides excellent wear resistance and durability under heavy loads. Its fully threaded, coarse UNC design ensures rapid installation and reliable holding power in machinery, automotive assemblies, and structural applications. By incorporating a Class 3A thread fit, it minimizes backlash and maintains precise alignment, reducing maintenance downtime. Ideal for high-strength fastening in equipment requiring robust, long-lasting connections, this screw delivers consistent performance while adhering to stringent industry standards.

Specification Summary & Compliance

This product features precise Class 3A thread fit with UNC coarse threads and a right-hand thread direction, ensuring accurate engagement. It conforms to ASTM A574 specifications for material and manufacturing quality, and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety and environmental adherence for global industrial use.