S-91772A640 5/16"-18 x 4" ASME B18.6.3 Stainless Steel Pan Head Phillips Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with Passivated 18-8 Stainless Steel construction, ideal for harsh environments and extended service life
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B70 hardness for reliable load-bearing performance
• Optimized fastening efficiency through UNC coarse threading and Class 2A thread fit, ensuring smooth installation and secure connections
• Enhanced durability in industrial applications with partial threading design that reduces stress concentration and improves fatigue resistance
• Broad compatibility and easy installation featuring a standard pan head with Phillips No. 4 drive for common tooling and consistent torque application
• Regulatory compliance assurance meeting ASME B18.6.3 standards, RoHS 3, and REACH for safe, quality-controlled use in global markets
• Versatile 4-inch length with 1 1/2" minimum thread engagement, providing flexibility for various material thicknesses and assembly requirements

Professional Applications & Engineering Value

This 5/16"-18 x 4" Rounded Head Screw delivers critical engineering value by addressing common industrial fastening challenges. The Passivated 18-8 Stainless Steel material provides excellent resistance to oxidation and chemical exposure, making it suitable for outdoor equipment, marine hardware, and food processing machinery where moisture and contaminants are concerns. Its UNC coarse thread and Class 2A fit facilitate rapid assembly in coarse-grained materials like castings or structural steel, reducing installation time while maintaining joint integrity. The partially threaded shank design concentrates clamping force precisely where needed, minimizing the risk of loosening under vibration—a key advantage in automotive, machinery, and construction applications. Combined with a pan head profile and Phillips drive, this screw offers a balanced solution for both aesthetic requirements and functional reliability in demanding B2B environments.

Specification Summary & Compliance

This screw adheres to precise dimensional standards with a Class 2A thread fit and UNC coarse thread (5/16"-18) ensuring consistent interchangeability. Manufacturing follows ASME B18.6.3 specifications for mechanical and geometric properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of restricted hazardous substances and supporting sustainable procurement practices.