S-90166A125 5/16"-18 x 2" ASTM F593, IFI 111 Stainless Steel Flanged Hex Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance thanks to 18-8 Stainless Steel construction, ensuring long-term reliability in harsh environments.
• Exceptional mechanical strength with a 70,000 psi tensile strength and Rockwell B80 hardness for demanding applications.
• Secure and stable fastening provided by the integrated flange, which acts as a built-in washer for improved load distribution.
• Easy and quick installation with an external hex drive and standard UNC coarse thread, compatible with common tools.
• Optimized thread engagement through a Class 2A thread fit, ensuring precise assembly and reducing the risk of cross-threading.
• Versatile partial threading design allows for a firm grip on materials while leaving the shank unthreaded for added shear strength.
• Compliance with major industry standards including ASTM F593, RoHS 3, and REACH, guaranteeing safety and regulatory adherence.

Professional Applications & Engineering Value

This 5/16"-18 UNC hex head screw is engineered to address common industrial challenges such as vibration loosening and material fatigue. The 18-8 Stainless Steel material offers excellent resistance to oxidation and chemical exposure, making it ideal for outdoor, marine, or chemical processing equipment. Its flanged design eliminates the need for a separate washer, reducing part count and assembly time while providing a larger bearing surface to prevent surface damage. The coarse UNC thread ensures rapid installation and reliable performance in low-density materials, while the partial threading enhances clamp load and resistance to shear forces. These features make it a top choice for machinery, structural frameworks, and heavy-duty assemblies where durability and corrosion resistance are critical.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including a Class 2A thread fit for consistent assembly and a UNC coarse thread profile. It is manufactured in compliance with ASTM F593 specifications, ensuring material and mechanical integrity. The product is also verified to be RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, confirming it is free from hazardous substances and safe for use in regulated markets.