S-91858A578 5/16"-18 x 1/2" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 316 stainless steel construction, ideal for harsh environments and extended service life
• Enhanced mechanical strength offering 70,000 psi tensile strength and Rockwell B80 hardness for reliable, high-stress fastening
• Optimized flush installation featuring an 82° countersink angle and undercut flat head design for a secure, seamless fit
• Effortless manual installation and removal with a standard slotted drive, compatible with common hand tools
• Consistent and reliable thread engagement due to Class 2A thread fit and fully threaded UNC coarse spacing
• Long-term durability and chemical resistance provided by the passivated finish, protecting against oxidation and wear
• Broad industry compliance meeting ASME B18.6.3 specifications and environmental standards like RoHS 3 and REACH

Professional Applications & Engineering Value

This 5/16"-18 UNC flat head screw is engineered from 316 stainless steel to address critical challenges in corrosive and high-moisture environments, such as marine, chemical processing, and outdoor infrastructure. The passivated finish significantly enhances surface durability, preventing galling and thread seizure during installation. Its fully threaded coarse spacing and Class 2A thread fit ensure quick assembly and vibration resistance, reducing maintenance needs in machinery, equipment panels, and structural frameworks. The undercut flat head with an 82° countersink allows for a flush mount, minimizing protrusions and improving safety in automated systems. Ideal for industrial applications requiring dependable, long-lasting fasteners that comply with rigorous ASME B18.6.3 standards.

Specification Summary & Compliance

This screw adheres to precise dimensional tolerances, including Class 2A thread fit for consistent performance and UNC coarse thread specifications. It is manufactured in compliance with ASME B18.6.3 for mechanical and dimensional integrity. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for global industrial use.