S-91583A631 1"-8 x 3 3/4" 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 structural integrity with 120,000 psi tensile strength and Rockwell C19 hardness, ensuring reliable performance under heavy loads and preventing premature failure in demanding applications.
• Superior corrosion resistance from the hot-dipped galvanized steel coating, significantly extending service life and reducing maintenance costs in harsh or outdoor environments.
• Optimized for secure connections with a 2-inch grip length and partially threaded design, providing maximum clamping force and preventing joint slippage in structural steel assemblies.
• Easy installation and high torque capability thanks to the external hex drive and 1 5/8" head width, allowing for efficient tightening with standard tools.
• Reliable thread engagement with a coarse UNC thread and Class 2A fit, ensuring easy starting, faster assembly, and consistent performance in structural frameworks.
• Full compliance with major industry standards including ASME B18.2.6, ASTM A325, and ASTM F3125, guaranteeing material quality, dimensional accuracy, and interoperability.
• Environmentally responsible manufacturing with RoHS 3 and REACH compliance, meeting strict global regulations for hazardous substances.

Professional Applications & Engineering Value

This Grade A325 hex head screw is engineered to solve critical challenges in structural fastening. The hot-dipped galvanized steel construction provides a robust barrier against rust and corrosion, making it ideal for bridges, building frames, and industrial machinery exposed to the elements. The partially threaded design with a defined grip length ensures that the clamping force is concentrated on the unthreaded shank, providing superior resistance to shear and vibration—a common failure point in dynamic loads. The coarse UNC thread facilitates quicker installation in steel-to-steel connections, reducing labor time while the external hex drive allows for high torque application without stripping. By combining high tensile strength with excellent corrosion protection, this fastener delivers long-term reliability, reduces the need for frequent inspections or replacements, and enhances the safety of structural applications.

Specification Summary & Compliance

This 1"-8 UNC hex head screw features a Class 2A thread fit for standard clearance and assembly ease. It is manufactured to meet dimensional specifications per ASME B18.2.6 and material requirements of ASTM A325 and ASTM F3125. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from restricted hazardous substances.