S-91251A606 1 1/4"-12 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 critical applications.
• Superior corrosion resistance from the black-oxide finish prolongs service life in harsh industrial environments, minimizing maintenance and replacement costs.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity and drive features through repeated use.
• Precision Class 2A thread fit with UNRF fine threads offers superior vibration resistance and secure fastening in high-stress assemblies.
• Partially threaded design allows for optimal clamping force distribution, preventing joint loosening in dynamic applications.
• 7/8" hex drive compatibility enables high-torque installation with standard tools, facilitating efficient assembly and disassembly procedures.
• Full regulatory compliance with ASTM A574, RoHS 3, and REACH ensures material consistency and environmental safety for global supply chain integration.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw delivers critical engineering solutions for heavy machinery, construction equipment, and industrial automation systems where vibration resistance and high tensile strength are paramount. The UNRF fine thread configuration maintains clamping force under dynamic loads, while the partially threaded rod design concentrates stress away from the head-to-shank junction. The black-oxide surface treatment provides essential corrosion protection without dimensional interference, making it ideal for precision assemblies requiring both maximum durability and consistent performance in demanding environments. With its 9-inch length and 1 1/4"-12 thread size, this fastener accommodates thick-section components common in structural frameworks and heavy equipment manufacturing.

Specification Summary & Compliance

Manufactured to ASTM A574 specifications with Class 2A thread fit tolerance and UNRF fine thread spacing. The 1 1/4"-12 thread maintains precise engagement, while the 3 1/8" minimum thread length ensures sufficient fastening surface. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations for environmental safety and material restrictions.