S-91251A817 5/8"-11 x 3 3/4" 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 consistent engagement and vibration resistance for secure assemblies.
• Partially threaded design allows for controlled clamping force and easier alignment in complex assemblies.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated use.
• 1/2" hex drive compatibility enables high-torque installation with standard tools, speeding up assembly processes.
• Compliance with RoHS 3 and REACH ensures environmental safety and regulatory acceptance for global industrial projects.

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these black-oxide alloy steel socket head cap screws deliver critical reliability where failure is not an option. The coarse UNRC thread design ensures rapid installation and superior resistance to loosening under vibration, making them ideal for heavy machinery, automotive assemblies, and structural frameworks. With a partially threaded shank, they provide optimal stress distribution, preventing joint fatigue in dynamic loads. The combination of 170,000 psi tensile strength and Rockwell C37 hardness addresses common challenges like shear forces and wear, while the black-oxide surface treatment defends against rust in humid or corrosive settings. These screws are trusted in aerospace, manufacturing, and construction sectors where precision and durability are paramount.

Specification Summary & Compliance

This socket head cap screw features a 5/8"-11 coarse thread with Class 3A thread fit for precise tolerance, ensuring consistent performance. It meets ASTM A574 specifications for high-strength alloy steel fasteners, guaranteeing material integrity and manufacturing consistency. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming adherence to environmental and safety standards for industrial use worldwide.