S-91099A482 5/16"-18 x 3/4" 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, ideal for harsh industrial environments
• Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for reliable performance under load
• Precise flush mounting enabled by the undercut flat head profile and 82° countersink angle for seamless surface integration
• Optimized drive engagement through Phillips No. 4 drive design, reducing cam-out and improving installation efficiency
• Consistent threading performance with fully threaded UNC coarse threads and Class 2A fit for secure fastening in various materials
• Regulatory compliance assurance meeting ASME B18.6.3 standards, RoHS 3, and REACH for global industrial applications
• Enhanced durability through complete passivation treatment, providing long-term reliability in demanding conditions

Professional Applications & Engineering Value

These 5/16"-18 UNC flat head screws deliver critical engineering solutions where surface flushness and corrosion resistance are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against oxidation and chemical exposure, making them ideal for marine equipment, food processing machinery, and outdoor industrial applications. The undercut flat head profile ensures perfect countersinking without material protrusion, while the coarse UNC threading offers superior holding power in both soft and hard materials. With full threading along the entire 3/4" length, these screws distribute clamping force evenly, preventing joint failure in vibration-prone environments. The combination of 80,000 psi tensile strength and standardized Phillips No. 4 drive makes them suitable for automated assembly processes while maintaining installation consistency.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance ensuring consistent engagement across applications. The UNC coarse thread (5/16"-18) provides optimal performance in most industrial materials. Compliant with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, containing no restricted substances above threshold limits. The 82° countersink angle matches standard chamfered holes for proper seating, while the 0.597" head diameter and 0.134" head height maintain industry-standard proportions for reliable performance.