S-91251A804 5/8"-11 x 2 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 under high-stress conditions, reducing the risk of fastener failure in critical assemblies.
• Superior corrosion resistance from the black-oxide coating extends service life in harsh industrial environments, minimizing maintenance and replacement costs.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections, enhancing assembly integrity.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive performance over repeated use.
• 1/2" hex drive design allows for easy installation with standard tools, improving efficiency in tight spaces without compromising torque application.
• Coarse UNRC threads enable quicker assembly and better performance in materials prone to stripping or where debris accumulation is a concern.
• Compliance with ASTM A574, RoHS 3, and REACH ensures adherence to industry standards and environmental regulations, supporting sustainable and safe manufacturing practices.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address common industrial challenges such as vibration loosening, corrosion, and high-load demands. The partially threaded design with coarse 5/8"-11 UNRC threads provides optimal grip in soft materials or applications requiring rapid assembly, while the socket head and 1/2" hex drive facilitate installation in confined spaces common in machinery, automotive, and heavy equipment. The black-oxide surface treatment enhances durability by resisting rust and wear, making it ideal for outdoor or humid environments. With a tensile strength of 170,000 psi and Rockwell C37 hardness, it delivers reliable performance in structural fastening, ensuring long-term stability and reducing downtime for maintenance.

Specification Summary & Compliance

This screw features a Class 3A thread fit for high precision and a coarse thread spacing with UNRC thread type, ensuring consistent engagement. It meets ASTM A574 specifications for high-strength socket head cap screws and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety and environmental responsibility in industrial use.