S-91251A156 1"-8 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, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from the black-oxide finish extends service life and maintains integrity in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections, minimizing loosening over time.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive features through repeated use.
• 3/4" hex drive design allows for high torque application with standard tools, facilitating efficient installation and removal.
• Partially threaded shank enables precise clamping force distribution, ideal for applications requiring controlled grip length.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and global regulatory acceptance for your projects.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in heavy machinery, automotive, and construction assemblies where high tensile strength and corrosion resistance are paramount. The 1"-8 coarse UNRC thread with Class 3A fit ensures rapid installation and reliable seating in high-vibration environments, reducing maintenance downtime. Its partially threaded design concentrates clamping force precisely, preventing joint slippage in structural applications. The 3/4" hex drive accommodates standard industrial tools, enabling efficient torque transfer without stripping. By combining ASTM A574 compliance with robust material properties, this fastener delivers consistent performance in demanding conditions, from manufacturing equipment to infrastructure projects, enhancing assembly longevity and safety.

Specification Summary & Compliance

This product features a 1"-8 coarse UNRC thread with Class 3A thread fit for precision engagement, a minimum thread length of 2-1/2", and a right-hand thread direction. It is manufactured in accordance with ASTM A574 specifications for high-strength alloy steel socket head cap screws, ensuring dimensional accuracy and mechanical properties. The fastener 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.