S-91251A725 1/2"-13 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 applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide coating extends service life in harsh industrial environments, minimizing maintenance needs.
• Precise Class 3A thread fit guarantees tight, secure fastening with minimal play, ideal for critical assemblies requiring exact tolerances.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity through repeated use and adjustments.
• Partially threaded design allows for controlled clamping force and easier alignment in specific mounting scenarios.
• 3/8" hex drive socket head enables high-torque installation with standard tools, speeding up assembly while preventing stripping.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and suitability for regulated industries.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address common industrial challenges such as vibration loosening, corrosion degradation, and high-load demands. The 1/2"-13 UNC coarse thread and Class 3A fit provide rapid assembly with superior holding power in heavy machinery, automotive systems, and structural frameworks. The black-oxide surface treatment not only resists rust and chemical exposure but also reduces galling during installation. With a partially threaded shank, it offers precise bearing surface contact, preventing joint slippage in dynamic applications. These screws deliver consistent performance in high-strength environments where reliability and compliance with ASTM A574 standards are critical for operational safety and longevity.

Specification Summary & Compliance

This socket head cap screw adheres to Class 3A thread tolerances for precision fit and is manufactured per ASTM A574 specifications. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring it is free from hazardous substances. The coarse UNC thread and right-hand direction follow standardized threading for compatibility with common industrial components.