S-91251A293 1/4"-20 x 5 1/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 PSI ensures reliable performance under high-stress conditions, 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.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, minimizing loosening and improving joint reliability.
• High hardness rating (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive features through repeated use and installation.
• Partially threaded design with UNC coarse threads allows for easier alignment and faster installation while providing strong holding power in a variety of materials.
• Hex socket drive (3/16") enables high torque application with standard tools, facilitating secure tightening in confined spaces without slippage.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material quality and environmental safety, meeting rigorous industrial and regulatory standards.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws are engineered to address critical challenges in industrial assembly, where vibration, corrosion, and high loads can compromise fastener integrity. The combination of alloy steel material and black-oxide surface treatment provides enhanced durability against rust and wear, making them ideal for machinery, automotive, and heavy equipment applications. The UNC coarse thread and Class 3A thread fit ensure quick, secure fastening with minimal cross-threading risks, while the partially threaded rod type offers flexibility in clamping and alignment. With a 5 1/4" length and hex drive style, these screws deliver consistent performance in tight spaces, supporting efficient maintenance and production workflows where reliability is paramount.

Specification Summary & Compliance

This product features precise Class 3A thread fit per UNC standards, with a thread size of 1/4"-20 and coarse thread spacing. Manufacturing adheres to ASTM A574 specifications, ensuring consistent quality and mechanical properties. Compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006), confirming environmental and safety standards are met for industrial use.