S-91251A130 5-40 x 5/8" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – With 170,000 psi tensile strength, this screw provides reliable fastening in high-stress and heavy-duty applications, reducing the risk of failure.
• Superior Corrosion Resistance – The black-oxide finish on alloy steel offers enhanced protection against rust and environmental factors, extending service life in harsh conditions.
• Precision Thread Fit – Class 3A thread fit ensures tight, secure connections with minimal backlash, improving assembly accuracy and vibration resistance.
• High Hardness for Durability – Rockwell C37 hardness provides excellent wear resistance, maintaining thread integrity and performance under repeated use.
• Wide Compatibility – UNC coarse threads and standard hex drive (3/32") allow for easy installation with common tools, speeding up assembly in industrial settings.
• Full Thread Engagement – Fully threaded design offers consistent clamping force along the entire 5/8" length, ideal for applications requiring uniform load distribution.
• Regulatory Compliance – Meets ASTM A574, RoHS 3, and REACH standards, ensuring safety, environmental responsibility, and suitability for global markets.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address critical challenges in demanding industrial environments. The combination of high tensile strength (170,000 psi) and Rockwell C37 hardness ensures it withstands heavy loads and repetitive stress without deforming, making it ideal for machinery, automotive assemblies, and construction equipment. The UNC coarse threads and Class 3A fit provide a secure, vibration-resistant connection that minimizes loosening in dynamic applications. Additionally, the black-oxide surface treatment enhances corrosion resistance, prolonging fastener life in humid or corrosive conditions. Its hex drive design allows for efficient installation in confined spaces, reducing labor time and improving productivity in B2B procurement scenarios where reliability and compliance with ASTM A574 are paramount.

Specification Summary & Compliance

This socket head cap screw features precise inch system measurements, including a 5-40 UNC thread size, 5/8" length, and Class 3A thread fit for high accuracy. It adheres to ASTM A574 specifications for quality and performance, and is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it meets environmental and safety standards for industrial use.