S-91274A228 5/16"-18 x 1/2" ASME B18.3, ASTM A574, ASTM B117 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the zinc-flake coating extends service life in harsh environments, minimizing maintenance and replacement costs.
• Precise Class 3A thread fit provides secure, vibration-resistant connections, enhancing assembly integrity and safety.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated use and disassembly.
• Standard hex drive (1/4") allows for easy installation and removal with common tools, improving workflow efficiency.
• Full threading ensures consistent engagement along the entire length, providing uniform clamping force and stability.
• Compliance with ASME B18.3 and ASTM A574 guarantees consistent quality and interoperability with standardized components.

Professional Applications & Engineering Value

This zinc-flake-coated alloy steel socket head cap screw is engineered to address critical challenges in demanding industrial settings. Its high tensile strength (170,000 psi) and Rockwell C37 hardness make it ideal for heavy machinery, automotive assemblies, and structural frameworks where dynamic loads and vibrations are common. The UNC coarse thread and Class 3A fit ensure rapid assembly with minimal cross-threading risks, while the corrosion-resistant zinc-flake coating protects against moisture, chemicals, and oxidation, extending service life in outdoor or corrosive environments. Fully threaded for maximum grip, it provides reliable fastening in high-strength applications requiring durability and compliance with industry standards.

Specification Summary & Compliance

This socket head cap screw features a 5/16"-18 UNC coarse thread with Class 3A precision tolerance for secure fitment. It is manufactured in accordance with ASME B18.3 and ASTM A574 specifications, ensuring dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its adherence to environmental and safety standards without restricted substances.