S-91781A591 5/16"-18 x 2" ASME B18.6.3 Stainless Steel Slotted Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with 18-8 Stainless Steel and passivated finish, ideal for harsh environments and extended service life.
• High mechanical strength offering 80,000 psi tensile strength and Rockwell B80 hardness for reliable performance under load.
• Precise and secure fastening ensured by Class 2A thread fit and UNC coarse threading, reducing cross-threading risks.
• Flush mounting capability with a standard 82° countersink angle and flat head design for a smooth, professional finish.
• Full thread engagement along the entire 2" length provides maximum grip and holding power in assemblies.
• Broad industry compliance meeting ASME B18.6.3 specifications, RoHS 3, and REACH regulations for safe, standardized use.
• Easy installation and removal with a slotted drive, compatible with standard hand tools for efficient maintenance.

Professional Applications & Engineering Value

This 5/16"-18 UNC Flat Head Slotted Screw is engineered from 18-8 Stainless Steel to address common industrial challenges like corrosion, vibration loosening, and mechanical stress. The passivated finish enhances surface durability, preventing rust in humid or chemical-exposed settings such as marine equipment, food processing machinery, and outdoor structures. Its coarse UNC threads and Class 2A fit ensure quick, accurate installation in metals and plastics, reducing assembly time and minimizing thread damage. Fully threaded for uniform load distribution, it is ideal for applications requiring high tensile strength and flush mounting, including automotive panels, electronic enclosures, and construction frameworks, delivering long-term reliability and compliance with global standards.

Specification Summary & Compliance

This screw features a 5/16"-18 UNC coarse thread with Class 2A thread fit for precise dimensional accuracy and interchangeability. Manufactured to ASME B18.6.3 specifications, it includes an 82° countersink angle, full threading, and inch-system measurements. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and safe for industrial and commercial use.