S-91251A871 6-32 x 2 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 high-stress conditions, reducing the risk of fastener failure.
• Superior hardness (Rockwell C37) provides excellent wear resistance and durability for long service life in demanding industrial environments.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance, protecting the screw from rust and extending its usability.
• Precise Class 3A thread fit guarantees secure, vibration-resistant connections with minimal backlash in critical assemblies.
• Partially threaded design with 6-32 UNRC coarse thread allows for easier alignment and faster installation while maintaining strong clamping force.
• Standard hex socket drive (7/64") enables high-torque application with common tools, preventing stripping and ensuring efficient assembly.
• 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 challenges in heavy-duty machinery, automotive, and aerospace applications where vibration loosening and material fatigue are concerns. The 6-32 coarse UNRC thread combined with a Class 3A fit provides superior resistance to dynamic loads, making it ideal for assemblies requiring repeated disassembly. The partially threaded shank concentrates strength where needed while facilitating precise positioning. With a 170,000 psi tensile strength and Rockwell C37 hardness, it outperforms standard fasteners in high-stress environments, reducing maintenance downtime and ensuring long-term operational reliability. The black-oxide surface treatment adds an extra layer of protection against corrosion in humid or chemically aggressive settings.

Specification Summary & Compliance

This socket head cap screw features a 6-32 thread size with coarse UNRC threading and Class 3A thread fit for precision engagement. It is manufactured to ASTM A574 specifications, ensuring consistent material properties and dimensional accuracy. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in environmentally conscious and regulated industrial markets. All measurements adhere to the inch system, with a length of 2-1/2" and a minimum thread length of 3/4".