S-91251A775 1 3/8"-6 x 8" 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 industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish prolongs service life in harsh environments, minimizing maintenance needs.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity over repeated use.
• Precise Class 2A thread fit allows for easy assembly while ensuring secure fastening, saving time during installation.
• Partially threaded design offers optimal clamping force control, ideal for applications requiring specific grip range.
• 1" hex drive compatibility enables high-torque installation with standard tools, enhancing efficiency in maintenance and assembly.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety, meeting global regulatory standards.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in heavy machinery, construction, and automotive sectors where vibration, high loads, and corrosive conditions are common. The 1 3/8"-6 UNC coarse thread design ensures rapid assembly and robust holding power, while the partially threaded shank concentrates clamping force precisely where needed, preventing joint loosening. With a Rockwell C37 hardness and 170,000 psi tensile strength, it withstands extreme operational stresses, reducing downtime and replacement costs. The black-oxide surface treatment adds a protective layer against rust and wear, making it suitable for outdoor or humid environments. Ideal for securing structural components, engine parts, and industrial equipment, this screw delivers consistent performance under demanding conditions, supported by ASTM A574 specifications for reliability.

Specification Summary & Compliance

This socket head cap screw features a 1 3/8"-6 UNC coarse thread with Class 2A thread fit for standard tolerance and easy installation. It is manufactured from alloy steel with dimensions including an 8" length, 1" hex drive, and partial threading. The product complies with ASTM A574 for material and mechanical properties, ensuring high quality. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free from hazardous substances and environmentally safe for industrial use.