S-91571A258 1/2"-13 x 3" 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 – With a 120,000 psi tensile rating, this screw provides superior resistance to breaking under extreme loads, ensuring long-term structural integrity in demanding applications.
• High Hardness for Wear Resistance – Rockwell C19 hardness minimizes wear and deformation during installation and use, extending the fastener's service life in high-stress environments.
• Optimized Grip and Thread Design – A 2" grip length and 1/2"-13 UNC coarse threads offer excellent clamping force and easier alignment, reducing installation time and improving joint stability.
• Precision Thread Fit – Class 2A thread fit ensures consistent, reliable engagement with nuts and tapped holes, minimizing the risk of cross-threading and assembly errors.
• Heavy-Duty Material Construction – Made from high-grade steel, this hex head screw withstands harsh conditions, including vibration and dynamic loads, without compromising performance.
• Broad Regulatory Compliance – Meets ASME B18.2.6, ASTM A325, and ASTM F3125 standards, plus RoHS 3 and REACH, ensuring safety, consistency, and environmental responsibility for global projects.
• Versatile Partially Threaded Shank – The partially threaded design concentrates stress on the unthreaded portion, enhancing fatigue resistance and making it ideal for connections requiring high shear strength.

Professional Applications & Engineering Value

Engineered for heavy-duty structural applications, this Grade A325 hex head screw addresses critical challenges in construction and industrial settings. Its high-strength steel composition and 1/2"-13 UNC coarse threading provide reliable fastening in materials prone to vibration and shock, such as steel frameworks, bridges, and machinery bases. The external hex drive allows for high-torque installation with standard tools, ensuring secure connections without stripping. By combining 120,000 psi tensile strength with a partially threaded shank, it minimizes stress concentration at the thread roots, reducing the risk of fatigue failure. This makes it a top choice for engineers seeking durable, ASME B18.2.6 compliant fasteners that maintain integrity under sustained loads.

Specification Summary & Compliance

This screw features precise Class 2A thread fit and UNC coarse threads for consistent performance. It complies with ASME B18.2.6, ASTM A325, and ASTM F3125 manufacturing specifications, ensuring dimensional accuracy and mechanical properties. Environmental adherence includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, supporting sustainable and safe usage in regulated industries.