S-91858A540 1/4"-20 x 3/4" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction and passivated finish, ideal for harsh environments and chemical exposure
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B80 hardness for reliable performance under heavy loads
• Precise thread engagement with Class 2A UNC coarse threads ensuring secure fastening and vibration resistance
• Full-length threading provides maximum grip and load distribution across the entire fastener length
• Standard 82° countersink angle enables flush mounting for clean, professional installations
• Slotted drive compatibility allows for quick installation with standard tools while maintaining a low-profile appearance
• Regulatory compliance assurance meeting ASME B18.6.3, RoHS 3, and REACH standards for quality and environmental safety

Professional Applications & Engineering Value

This 316 stainless steel flat head screw delivers critical performance advantages in demanding industrial applications where corrosion resistance and structural integrity are paramount. The combination of marine-grade 316 stainless steel and passivated surface treatment provides exceptional protection against saltwater, chemicals, and atmospheric corrosion, making it ideal for marine equipment, chemical processing plants, and outdoor infrastructure. The UNC coarse threading and Class 2A thread fit ensure reliable installation in various materials while resisting vibration-induced loosening. The flat head design with 82° countersink creates seamless, flush-mounted connections in machinery, electrical enclosures, and structural assemblies where protruding fasteners are unacceptable. These industrial screws maintain their mechanical properties in high-temperature and corrosive environments, providing long-term reliability that reduces maintenance frequency and replacement costs.

Specification Summary & Compliance

This fastener features precise 1/4"-20 UNC coarse threads with Class 2A thread fit tolerance for consistent engagement and reliable performance. Manufacturing complies with ASME B18.6.3 specifications for dimensional accuracy and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) restrictions on hazardous substances and REACH (EC 1907/2006) regulations for chemical safety, ensuring environmental responsibility and workplace safety standards are met for industrial applications worldwide.