S-91255A580 5/16"-18 x 5/8" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, extending service life in demanding industrial environments.
• Superior tensile strength of 120,000 psi ensures reliable performance under high-stress applications, reducing failure risks.
• Precise Class 3A thread fit guarantees secure fastening with minimal play, enhancing assembly integrity.
• High Rockwell C39 hardness provides excellent wear resistance, maintaining thread integrity through repeated use.
• Hex drive design (3/16") allows for efficient torque application, speeding up installation and reducing tool slippage.
• Fully threaded UNC coarse thread enables quick engagement and strong holding power in various materials.
• Compliance with ASME B18.3 and ASTM F835 ensures consistent quality and interoperability in industrial systems.

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these Black-Oxide Alloy Steel Rounded Head Screws address critical challenges in machinery assembly, automotive components, and structural frameworks. The 5/16"-18 UNC coarse thread with Class 3A fit ensures rapid, secure fastening in metals and composites, minimizing installation time while providing robust clamping force. The rounded button head and hex drive design facilitate easy access in confined spaces, reducing assembly errors. With 120,000 psi tensile strength and Rockwell C39 hardness, these screws resist vibration loosening and mechanical stress, making them ideal for high-load environments where reliability is paramount. Their black-oxide surface treatment adds a protective layer against oxidation, extending service life in humid or corrosive conditions without compromising performance.

Specification Summary & Compliance

This product adheres to Class 3A thread tolerance for precise fit, with UNC coarse threading and right-hand direction per standard specifications. Manufacturing complies with ASME B18.3 and ASTM F835 standards, ensuring dimensional accuracy and mechanical properties. Environmental and safety regulations are met, including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) adherence, confirming the absence of restricted substances for global industrial use.