S-91251A495 5/8"-18 x 1" 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.
• Precision Class 3A thread fit provides superior engagement and vibration resistance, ideal for critical assemblies requiring tight tolerances.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance, extending service life in demanding industrial environments.
• Fine UNRF threads deliver improved clamping force and better load distribution compared to coarse threads.
• 1/2" hex drive design allows for high-torque installation with standard tools, facilitating efficient assembly and maintenance.
• Full threading along the 1" length ensures consistent grip and adjustability across the entire fastener.
• Rockwell C37 hardness provides excellent wear resistance, maintaining thread integrity through repeated use.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address common industrial challenges such as vibration loosening and material fatigue. The Class 3A UNRF fine threads create a secure, tight fit that minimizes back-off in high-vibration applications like heavy machinery, automotive systems, and precision equipment. The alloy steel construction combined with the black-oxide surface treatment resists rust and corrosion, making it suitable for environments exposed to moisture or chemicals. Its high tensile strength and Rockwell C37 hardness ensure it can withstand extreme loads without deforming, providing long-term reliability in critical assemblies where fastener failure is not an option.

Specification Summary & Compliance

This socket head cap screw features a 5/8"-18 UNRF Class 3A thread with fine spacing and right-hand direction, ensuring precise fit and alignment. It is fully threaded over a 1" length and manufactured to meet ASTM A574 specifications for high-strength fasteners. The product is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its adherence to environmental and safety standards for industrial use.