S-91251A177 1 1/8"-7 x 9" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under extreme loads and prevents fastener failure in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life and reducing maintenance needs in harsh environments.
• High torque transmission capability with the 7/8" hex drive, allowing for secure installation and removal without stripping the socket.
• Optimized for high-vibration environments due to the coarse (1 1/8"-7) UNRC thread and Class 2A fit, which resists loosening.
• Enhanced durability and wear resistance from the Rockwell C37 hardness, maintaining thread integrity and dimensional stability over time.
• Versatile partial threading provides an unthreaded shoulder for precise clamping and alignment in assembled components.
• Compliance with major industry and environmental standards (ASTM A574, RoHS 3, REACH) guarantees material quality and regulatory acceptance for global supply chains.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, this Black-Oxide Alloy Steel Socket Head Cap Screw solves critical challenges in machinery, construction, and automotive assemblies. The alloy steel core, combined with a black-oxide surface treatment, offers excellent resistance to corrosion and wear, which is vital in environments exposed to moisture, chemicals, or high friction. The coarse UNRC thread (1 1/8"-7) and Class 2A thread fit ensure quick assembly and superior resistance to vibrational loosening, making these socket head cap screws ideal for high-stress connections. The large 7/8" hex drive allows for high torque application, reducing the risk of tool slippage and ensuring a secure, reliable fastening in critical structural and mechanical systems.

Specification Summary & Compliance

This socket head cap screw features a 1 1/8"-7 coarse UNRC thread with a Class 2A thread fit for consistent dimensional accuracy and ease of assembly. It is manufactured in accordance with ASTM A574 specifications, ensuring high strength and reliability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted hazardous substances and supporting environmentally responsible procurement.