S-91251A562 1/4"-20 x 6 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 extreme loads, reducing the risk of fastener failure in critical applications.
• Superior corrosion resistance from the black-oxide finish extends service life in harsh industrial environments, minimizing maintenance and replacement costs.
• Precise Class 3A thread fit guarantees secure, vibration-resistant assemblies, enhancing joint integrity and operational safety.
• Partially threaded design allows for optimal clamping force and easier alignment, speeding up installation in complex machinery.
• High hardness (Rockwell C37) provides excellent wear resistance, maintaining thread integrity through repeated use and high-stress conditions.
• Hex socket drive (3/16") enables high-torque installation with standard tools, facilitating efficient assembly and disassembly in confined spaces.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency and environmental safety, meeting global regulatory standards for industrial use.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common challenges in heavy-duty and precision applications. The UNC coarse thread and Class 3A fit provide superior resistance to loosening under vibration, making it ideal for machinery, automotive assemblies, and structural frameworks. The partially threaded rod type ensures that the unthreaded shank bears shear loads effectively, while the threaded portion delivers consistent clamping force. With a Rockwell C37 hardness and 170,000 psi tensile strength, it withstands high-stress environments without deformation, reducing downtime and maintenance. The black-oxide surface treatment offers added corrosion protection, extending lifespan in humid or chemically exposed settings. These features make it a reliable choice for engineers seeking durability, compliance, and performance in industrial fasteners.

Specification Summary & Compliance

This socket head cap screw features a 1/4"-20 UNC coarse thread with Class 3A thread fit for precise tolerance, ensuring consistent engagement and load distribution. The partially threaded design includes a minimum thread length of 1 inch on a total length of 6-1/4 inches. It conforms to ASTM A574 specifications for high-strength alloy steel fasteners, guaranteeing material and manufacturing consistency. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, adhering to environmental and safety regulations for hazardous substances.