S-91251A328 5/16"-24 x 1 5/8" 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 black-oxide coating extends service life in demanding industrial environments
• Precision Class 3A thread fit provides superior engagement and vibration resistance compared to standard Class 2A fasteners
• Partially threaded design allows for optimal clamping force distribution and easier installation in precision assemblies
• Standard hex socket drive enables high-torque installation and removal with common industrial tools
• Fine UNF thread pattern delivers enhanced holding power and superior resistance to loosening under vibration
• Rockwell C37 hardness rating maintains thread integrity and drive socket durability through repeated use

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these black-oxide alloy steel socket head cap screws provide critical solutions for machinery, automotive, and heavy equipment assemblies where vibration resistance and high tensile strength are paramount. The fine UNF thread configuration (5/16"-24) ensures superior clamping force maintenance in dynamic loading conditions, while the partially threaded design concentrates engagement where needed most. The ASTM A574 certification guarantees consistent material properties and manufacturing quality, making these fasteners ideal for precision engineering applications requiring reliable, repeatable performance. The combination of 170,000 psi tensile strength and Rockwell C37 hardness ensures these screws withstand extreme operational stresses without compromising thread integrity or drive socket functionality.

Specification Summary & Compliance

These socket head cap screws feature precision Class 3A thread fit with 5/16"-24 UNF fine threads and 1 5/8" length in the inch measurement system. Manufactured to ASTM A574 specifications with black-oxide surface treatment on alloy steel. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across global industrial markets. The 1/4" hex drive and standard socket head profile provide consistent tool engagement for reliable installation.