S-91771A595 5/16"-18 x 3" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with passivated 18-8 stainless steel construction, ideal for harsh industrial environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Optimized drive engagement through Phillips No. 4 drive design, reducing cam-out and improving installation efficiency
• Precision flush mounting with 82° countersink angle and standard flat head profile for seamless surface integration
• Secure coarse thread engagement using UNC 5/16"-18 threads with Class 2A fit for vibration resistance in demanding applications
• Versatile partial threading allowing unthreaded shank sections for precise clamping and alignment control
• Full regulatory compliance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH

Professional Applications & Engineering Value

Engineered for industrial assembly challenges, these 5/16"-18 UNC flat head screws deliver critical performance where corrosion resistance and structural integrity matter most. The passivated 18-8 stainless steel construction provides lasting protection against chemical exposure and atmospheric corrosion, while the 80,000 psi tensile strength ensures reliable fastening in machinery, structural frameworks, and equipment subjected to dynamic loads. The partially threaded design combined with Class 2A thread fit offers superior vibration resistance, making these Phillips drive screws ideal for automotive, marine, and manufacturing applications where precise unthreaded shank sections prevent joint loosening. The 82° countersink angle ensures clean, flush installations in metal fabrication and woodworking projects.

Specification Summary & Compliance

These 3" flat head screws maintain precision Class 2A thread fit per UNC standards with coarse 5/16"-18 threading and right-hand orientation. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring safe use across global industrial markets.