S-91771A599 5/16"-18 x 4" 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 for extended service life in harsh environments
• High tensile strength of 80,000 psi ensures reliable performance under heavy loads and vibration
• Precise Class 2A thread fit provides smooth installation and secure fastening in coarse UNC threading applications
• Optimized 82° countersink angle allows for flush mounting and clean aesthetic finish in metal and wood assemblies
• Partially threaded design offers superior clamping force control in structural and machinery applications
• Phillips No. 4 drive compatibility enables efficient installation with standard industrial tools
• Full regulatory compliance with ASME B18.6.3, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head screws deliver exceptional engineering value through their passivated 18-8 stainless steel composition and precision manufacturing. The combination of 80,000 psi tensile strength and Rockwell B80 hardness provides critical resistance to shear forces and material fatigue in demanding applications. The partially threaded configuration with coarse UNC threading ensures maximum grip strength in structural steel, heavy machinery, and industrial equipment assemblies. The 82° countersink angle and standard flat head profile create seamless transitions in metal fabrication, automotive components, and architectural installations while preventing surface protrusion issues. These industrial flat head screws solve common fastening challenges by maintaining integrity in corrosive environments while meeting strict dimensional tolerances for precision engineering projects.

Specification Summary & Compliance

Manufactured to exact ASME B18.6.3 specifications with Class 2A thread fit for consistent dimensional accuracy. Features 5/16"-18 UNC coarse threading with 1 1/2" minimum thread length and right-hand thread direction. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The passivated 18-8 stainless steel construction ensures corrosion resistance while maintaining 80,000 psi tensile strength and Rockwell B80 hardness for industrial durability.