S-91251A478 3/8"-24 x 3 1/4" 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.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies in critical applications.
• Fine UNF threads offer improved load distribution and better sealing capabilities compared to coarse threads.
• Partially threaded design allows for controlled clamping force and easier alignment in assembled components.
• High hardness (Rockwell C37) enhances wear resistance and durability, minimizing damage during installation and use.
• Hex socket drive enables high-torque installation with standard tools, reducing stripping and improving efficiency.

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 3/8"-24 UNF fine thread and Class 3A fit ensure precise engagement in machinery, automotive, and aerospace assemblies, where tolerance integrity is critical. The black-oxide surface treatment provides a durable barrier against moisture and chemicals, making it ideal for outdoor or corrosive environments. Combined with its 170,000 PSI tensile strength and partially threaded shank, this fastener delivers consistent clamping force and resists shear stresses, reducing maintenance needs and enhancing operational safety in heavy-duty applications.

Specification Summary & Compliance

This socket head cap screw adheres to ASTM A574 specifications, ensuring consistent quality and performance. The Class 3A thread provides tight dimensional accuracy for secure fits, while the 3/8"-24 UNF fine thread follows standardized pitch requirements. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environmentally sensitive and regulated industries without hazardous substances.