S-91251A027 1/2"-20 x 2 3/4" 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.
• Durable black-oxide coating on alloy steel provides enhanced corrosion resistance, extending service life in harsh industrial environments.
• Precise Class 3A thread fit offers superior engagement and vibration resistance, minimizing loosening in critical assemblies.
• Hex socket drive design allows for high-torque installation with standard tools, improving assembly efficiency and reducing strip-out.
• Fine UNRF threading delivers better load distribution and sealing capabilities compared to coarse threads, ideal for precision equipment.
• Partially threaded shank enables accurate clamping without thread interference, ensuring secure fastening in dynamic applications.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material consistency and environmental safety for global supply chain integration.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common industrial challenges such as vibration-induced loosening and corrosion in demanding settings. The Class 3A fine UNRF thread provides tight tolerances that enhance joint integrity in machinery, automotive, and aerospace assemblies where precision is critical. Its high tensile strength and Rockwell C37 hardness ensure it withstands extreme loads without deformation, making it suitable for heavy-duty fixtures and equipment frames. The hex drive facilitates easy installation in confined spaces, while the black-oxide surface treatment adds a protective layer against moisture and chemicals, reducing maintenance needs. Ideal for applications requiring reliable, high-strength fasteners, this screw delivers consistent performance in manufacturing, construction, and OEM projects.

Specification Summary & Compliance

This product features a 1/2"-20 UNRF fine thread with Class 3A fit for precise thread engagement and dimensional accuracy. It meets ASTM A574 specifications for high-strength alloy steel socket head cap screws, ensuring material and manufacturing consistency. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards confirms adherence to environmental and safety regulations, supporting sustainable and safe usage in various industries.