S-91251A816 5/8"-11 x 5 1/2" 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, reducing the risk of fastener failure in critical applications.
• Superior corrosion resistance from the black-oxide finish prolongs service life in harsh or humid industrial environments, minimizing maintenance needs.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, enhancing joint integrity.
• High hardness rating (Rockwell C37) offers excellent wear resistance, maintaining thread form and drive integrity through repeated use.
• Heavy-duty 1/2" hex drive allows for high torque application, ensuring easy installation and removal with standard tools.
• Coarse UNRC threads enable quick assembly and better performance in materials prone to stripping or where debris is present.
• Compliance with RoHS 3 and REACH ensures environmental and safety standards are met, supporting sustainable and regulated operations.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, this black-oxide alloy steel socket head cap screw combines high tensile strength and corrosion resistance to address common challenges in machinery, automotive, and construction sectors. The partially threaded design with a minimum thread length of 1 3/4" provides optimal grip in tapped holes or nuts, reducing stress concentration. Its coarse 5/8"-11 UNRC threads and Class 3A fit ensure rapid, secure fastening even in vibrating environments, while the standard socket head profile and 1/2" hex drive facilitate efficient installation in confined spaces. Ideal for heavy-duty assemblies requiring 170,000 psi tensile strength and long-term durability, this fastener minimizes downtime and enhances structural reliability.

Specification Summary & Compliance

This socket head cap screw adheres to ASTM A574 specifications, with a Class 3A thread fit for precision and a coarse UNRC thread type (5/8"-11). Dimensions include a length of 5 1/2", head diameter of 15/16", and drive size of 1/2". It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), ensuring it meets stringent environmental and health standards for industrial use.