S-91251A962 1 1/2"-6 x 5 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 extreme loads, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life and maintaining integrity in harsh industrial environments.
• High hardness rating (Rockwell C37) provides excellent wear resistance, minimizing deformation and ensuring long-term dimensional stability.
• Coarse UNRC thread design allows for quicker installation and better grip in softer materials or where vibration resistance is critical.
• Hex socket drive with 1" drive size offers secure tool engagement and high torque transmission, facilitating efficient assembly and disassembly.
• Partially threaded shank enables precise clamping force distribution, ideal for applications requiring specific unthreaded grip lengths.
• Compliance with ASTM A574 guarantees consistent quality and mechanical properties, ensuring interoperability and reliability in engineered systems.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common industrial challenges such as vibration loosening, high-stress fatigue, and environmental corrosion. The coarse UNRC thread with Class 2A fit ensures rapid installation and robust holding power in machinery, automotive assemblies, and heavy equipment, where partial threading allows for optimized load-bearing sections. The hex drive socket design accommodates high-torque tools, reducing assembly time while maintaining precise alignment. Ideal for construction, manufacturing, and automotive sectors, this fastener delivers consistent performance under dynamic loads, backed by its high tensile strength and hardened material properties that prevent stripping and extend maintenance intervals.

Specification Summary & Compliance

This socket head cap screw adheres to ASTM A574 specifications, with precise thread dimensions of 1 1/2"-6 coarse (UNRC) and a Class 2A thread fit for standard tolerance applications. It meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance, ensuring environmental safety and regulatory adherence. The screw features a 5 1/2" length with a minimum thread length of 3 3/4", manufactured from alloy steel with a black-oxide surface treatment for enhanced durability and corrosion resistance.