S-91255A576 5/16"-18 x 3/8" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 120,000 psi ensures reliable performance under heavy loads and vibration, reducing failure risks in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure fastening, minimizing loosening and improving assembly integrity.
• Fully threaded coarse UNC design allows for faster installation and stronger grip in a wide range of materials, saving time on the production line.
• Rounded button head with hex drive offers a low-profile, aesthetically clean finish while enabling high-torque application with standard tools.
• High hardness (Rockwell C39) enhances wear resistance, maintaining thread integrity through repeated use and disassembly.
• Compliance with major standards including ASME B18.3 and ASTM F835 ensures consistent quality and interoperability in regulated industries.

Professional Applications & Engineering Value

Engineered for industrial and heavy-duty applications, these Black-Oxide Alloy Steel Rounded Head Hex Screws address critical challenges in machinery, automotive, and construction sectors. The coarse UNC threading and Class 3A fit provide excellent resistance to vibration loosening, a common pain point in dynamic environments. Combined with a fully threaded design, they ensure maximum thread engagement for robust connections in metal, wood, and composite assemblies. The black-oxide surface treatment not only adds a layer of corrosion protection but also reduces galling during installation, streamlining maintenance and reducing downtime. Ideal for high-stress fastening where reliability and compliance with ASME B18.3 and ASTM F835 are non-negotiable, these screws deliver consistent performance that meets the rigorous demands of B2B procurement.

Specification Summary & Compliance

This screw features a 5/16"-18 UNC coarse thread with Class 3A precision fit, ensuring tight dimensional accuracy and reliable engagement. Manufacturing adheres to ASME B18.3 and ASTM F835 specifications, guaranteeing uniformity and strength. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety for use in environments requiring strict environmental and health standards.