S-91251A578 5/16"-18 x 1/2" 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 applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish extends service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies.
• Fully threaded design allows for maximum grip and uniform clamping force along the entire length.
• High hardness (Rockwell C37) enhances wear resistance, maintaining thread integrity through repeated use.
• Coarse UNC threads enable quicker installation and better performance in materials prone to stripping.
• Compliance with RoHS 3 and REACH ensures environmental safety and meets global regulatory standards.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, these black-oxide alloy steel socket head cap screws address critical challenges like vibration loosening and corrosion in machinery, automotive, and heavy equipment assemblies. The 5/16"-18 UNC coarse thread and Class 3A fit provide superior holding power, reducing maintenance needs and downtime. With a 170,000 psi tensile strength and Rockwell C37 hardness, they withstand extreme loads and repetitive stress, making them ideal for high-performance applications where reliability is non-negotiable. The fully threaded rod ensures consistent load distribution, enhancing joint integrity in critical fastening points.

Specification Summary & Compliance

This socket head cap screw features a 5/16"-18 UNC coarse thread with Class 3A thread fit for precision assembly. Manufactured to ASTM A574 specifications, it includes a 1/4" hex drive and 1/2" length. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring adherence to environmental and safety standards.