S-91251A111 3/8"-16 x 6 1/2" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi provides superior load-bearing capacity and resistance to failure in demanding applications.
• High hardness rating of Rockwell C37 ensures excellent wear resistance and long-term durability under repetitive stress.
• Precision Class 3A thread fit guarantees secure, vibration-resistant assemblies with minimal risk of loosening.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance for extended service life in harsh environments.
• Hex socket drive design allows for high torque application and easy installation in confined spaces.
• Partially threaded shank provides optimal grip length for precise clamping without unnecessary thread engagement.
• Full regulatory compliance with ASTM A574, RoHS 3, and REACH ensures material safety and meets international industrial standards.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to solve critical fastening challenges in heavy machinery, automotive assemblies, and precision equipment. The 3/8"-16 coarse UNRC threads with Class 3A fit ensure rapid installation and reliable performance in high-vibration environments where thread stripping is a concern. The combination of 170,000 psi tensile strength and Rockwell C37 hardness provides exceptional resistance to dynamic loads and mechanical shock, making it ideal for structural applications requiring repeated disassembly. The hex socket drive accommodates high torque values while the black-oxide surface treatment protects against oxidation in industrial settings, delivering long-term reliability for OEM and MRO operations.

Specification Summary & Compliance

This fastener maintains precision Class 3A thread tolerances with 3/8"-16 coarse UNRC threads and 1-1/4" minimum thread length. Manufacturing strictly follows ASTM A574 specifications for high-strength socket head cap screws. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material traceability for global industrial applications.