S-91251A332 5/16"-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 in high-stress industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh environments and minimizing maintenance needs.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, enhancing joint integrity.
• Fine UNF thread design offers improved load distribution and better resistance to loosening under dynamic conditions compared to coarse threads.
• Hex socket drive with 1/4" size allows for high-torque installation in confined spaces, streamlining assembly processes.
• Partially threaded shank enables accurate clamping without thread interference, ideal for precision-machined components.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and global regulatory acceptance for B2B procurement.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address critical challenges in demanding sectors like machinery, automotive, and aerospace. The UNF fine thread (5/16"-24) and Class 3A fit deliver superior resistance to vibration and fatigue, preventing joint failure in dynamic systems. The alloy steel construction with a Rockwell C37 hardness balances strength and ductility, while the black-oxide surface treatment combats corrosion without compromising dimensional accuracy. Its 3 1/4" length and partially threaded design make it ideal for applications requiring precise unthreaded grip areas, such as in assembly jigs or high-precision equipment, ensuring long-term reliability and reduced downtime.

Specification Summary & Compliance

This socket head cap screw adheres to inch system measurements with a 5/16"-24 UNF fine thread and Class 3A thread fit for high precision. It meets ASTM A574 specifications for alloy steel socket head cap screws, ensuring consistent manufacturing quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in environmentally sensitive and international markets.