S-91263A578 5/16"-18 x 2" ASTM F835 Alloy Steel Hex Drive Flat Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 130,000 psi ensures reliable performance in demanding heavy-duty applications, reducing the risk of fastener failure.
• Superior corrosion resistance from zinc-plated alloy steel construction extends service life and maintains integrity in harsh industrial environments.
• Precise Class 3A thread fit provides secure, vibration-resistant connections, minimizing loosening and improving assembly reliability.
• Standard 82° countersink angle allows for a flush, professional finish, enhancing safety and aesthetics in mounted assemblies.
• High Rockwell C39 hardness offers excellent wear resistance, ensuring durability and long-term performance under mechanical stress.
• Coarse UNC threading enables quicker installation and better grip in a variety of materials, speeding up production and reducing labor time.
• Compliance with ASTM F835, RoHS 3, and REACH guarantees adherence to rigorous quality, safety, and environmental standards for global industrial use.

Professional Applications & Engineering Value

These zinc-plated alloy steel flat head screws are engineered to address critical challenges in industrial fastening, such as corrosion, vibration loosening, and high-stress failure. The partially threaded design with UNC coarse threads ensures optimal grip and ease of installation in materials like metal and hardwood, reducing assembly time while maintaining joint integrity. The hex drive allows for high-torque application, preventing cam-out and ensuring a secure fit in heavy machinery, construction frameworks, and automotive assemblies. With a 130,000 psi tensile strength and Rockwell C39 hardness, these screws withstand extreme loads and repetitive stress, making them ideal for applications where reliability and longevity are paramount. The zinc plating provides an added layer of protection against rust and environmental factors, ensuring consistent performance in outdoor or corrosive settings.

Specification Summary & Compliance

This product features precise Class 3A thread fit and UNC coarse threading with a thread size of 5/16"-18, ensuring tight tolerances for secure fastening. It meets ASTM F835 specifications for mechanical properties and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming adherence to environmental and safety standards. The screws are manufactured with a standard 82° countersink angle and partial threading up to a minimum length of 1 1/8", providing consistent performance in industrial applications.