S-91571A324 7/8"-9 x 3 1/2" ASME B18.2.6, ASTM A325, ASTM F3125 Medium-Strength Steel Heavy Hex Head Screws for Structural Applications

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance under extreme loads, reducing the risk of fastener failure in critical applications
• Rockwell C19 hardness rating provides superior resistance to wear and deformation, extending service life in high-stress environments
• Partially threaded design with 2" grip length offers optimal clamping force distribution and prevents joint loosening in structural connections
• Class 2A thread fit with UNC coarse threading enables faster installation and better resistance to vibration-induced loosening
• External hex drive with 1 7/16" head width delivers maximum torque transmission and easier installation with standard tools
• Full compliance with ASTM A325, ASTM F3125 and ASME B18.2.6 guarantees consistent quality and performance meeting industry standards
• RoHS 3 and REACH environmental compliance ensures safe usage in regulated industries and environmentally sensitive applications

Professional Applications & Engineering Value

This Grade A325 steel hex head screw delivers critical engineering solutions for heavy-duty construction and structural applications where failure is not an option. The 7/8"-9 UNC coarse thread configuration provides superior holding power in steel-to-steel connections, while the partially threaded design ensures that the unthreaded shank bears against connected materials for enhanced shear strength. The external hex drive allows for high-torque installation without stripping, making these industrial hex screws ideal for structural steel framing, bridge construction, and heavy machinery assembly. The combination of 120,000 psi tensile strength and Rockwell C19 hardness addresses the common industrial challenge of fastener fatigue and deformation under dynamic loading conditions.

Specification Summary & Compliance

This heavy-duty hex head screw features precise Class 2A thread fit with UNC coarse threading (7/8"-9) and right-hand thread direction. Manufacturing and quality control adhere to ASME B18.2.6, ASTM A325, and ASTM F3125 specifications, ensuring dimensional accuracy and performance reliability. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for use in regulated industries and international markets.