S-91251A896 7/8"-9 x 6" 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.
• Black-oxide coating on alloy steel provides corrosion resistance and a durable, non-reflective finish suitable for harsh industrial environments.
• Class 3A thread fit offers superior precision and tighter tolerances for secure, vibration-resistant assemblies in critical machinery.
• 3/4" hex drive and standard socket head allow for high-torque installation with common tools, speeding up assembly and maintenance.
• Partially threaded design with 2 1/4" minimum thread length provides optimal grip and clamping force where full threading isn't required.
• Rockwell C37 hardness ensures excellent wear resistance and longevity, minimizing replacement needs in demanding applications.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material consistency, environmental safety, and adherence to international industrial standards.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common challenges in heavy-duty industrial settings, such as vibration loosening and material fatigue. The UNRC coarse thread and Class 3A fit ensure quick assembly and reliable holding power in metals and composites, reducing maintenance downtime. With a 170,000 psi tensile strength and Rockwell C37 hardness, it withstands extreme loads and repetitive stress in machinery, automotive, and construction applications. The black-oxide surface treatment adds corrosion resistance without compromising dimensional integrity, making it ideal for exposed or humid environments where durability is critical.

Specification Summary & Compliance

This screw features a 7/8"-9 UNRC coarse thread with Class 3A precision fit, ensuring consistent engagement and alignment. It is manufactured to ASTM A574 specifications for high-strength alloy steel fasteners, guaranteeing material and performance reliability. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in regulated industries without hazardous substances.