S-91500A363 1/4"-20 x 4" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh chemical and marine environments
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B80 hardness for heavy-duty applications
• Enhanced environmental protection through passivated finish, extending service life in corrosive conditions
• Reliable fastening performance with fully threaded UNC coarse spacing providing maximum thread engagement
• Precision thread fit with Class 2A tolerance ensuring consistent installation and vibration resistance
• Optimized flush mounting with 82° countersink angle and standard flat head profile for seamless surface integration
• Industry compliance assurance meeting ASME B18.6.3 specifications and environmental regulations

Professional Applications & Engineering Value

These 316 stainless steel flat head screws deliver critical performance advantages in demanding industrial settings where corrosion resistance and structural integrity are paramount. The passivated finish creates an additional protective oxide layer, significantly enhancing the material's natural resistance to chlorides, acids, and industrial chemicals. With fully threaded UNC coarse spacing and Class 2A thread fit, these fasteners provide superior holding power in metal assemblies, machinery, and structural applications where vibration resistance is essential. The flat head design with 82° countersink ensures flush mounting in predrilled surfaces, making them ideal for applications requiring smooth finished surfaces without protrusions. These screws are engineered to maintain clamping force and thread integrity in high-stress environments, from chemical processing equipment to marine hardware and outdoor infrastructure.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 2A thread fit tolerance and UNC coarse thread specification (1/4"-20). Complies with ASME B18.6.3 mechanical and dimensional requirements. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for restricted substances. Features standard 82° countersink angle and Phillips No. 3 drive for consistent installation performance across industrial applications.