S-91251A515 5-40 x 1 3/8" 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 prolongs service life in harsh industrial environments, minimizing maintenance and replacement costs.
• Precise Class 3A thread fit guarantees secure, vibration-resistant assemblies with excellent engagement, enhancing overall joint integrity.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity through repeated installations and removals.
• Partially threaded design allows for controlled clamping force and easier alignment in assemblies, improving installation efficiency.
• Compliance with ASTM A574 and RoHS 3/REACH ensures material consistency and environmental safety, meeting strict industry and regulatory standards.
• Coarse UNC threads enable quick assembly and disassembly, reducing labor time in maintenance and production cycles.

Professional Applications & Engineering Value

Engineered for industrial applications requiring robust fastening solutions, these black-oxide alloy steel socket head cap screws address common challenges like vibration loosening and environmental degradation. The 5-40 UNC coarse thread design ensures rapid installation in machinery, automotive, and heavy equipment, while the Class 3A thread fit provides tight tolerances that resist shock and dynamic loads. The partially threaded rod type allows precise load distribution, preventing stress concentration. With a 3/32" hex drive and standard socket head profile, these screws offer easy access in confined spaces, enhancing assembly efficiency and reducing downtime in maintenance operations.

Specification Summary & Compliance

This product adheres to Class 3A thread fit for high precision, with UNC coarse threads and a right-hand thread direction. Manufactured in compliance with ASTM A574 specifications, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards, ensuring safety and consistency for global industrial use.