S-91247A599 5/16"-18 x 4" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capability with 120,000 psi tensile strength for reliable performance in demanding applications
• Superior corrosion resistance through zinc plating, extending service life in various industrial environments
• Optimized thread engagement with UNC coarse threading and Class 2A fit for faster assembly and secure fastening
• Enhanced durability from Rockwell C25 hardness, maintaining structural integrity under repeated stress
• Efficient installation and removal with external hex drive design for standard tool compatibility
• Versatile partial threading allowing for both clamping and alignment functions in assembly operations
• Regulatory compliance assurance meeting ASME B18.2.1 and SAE J429 standards for quality and safety

Professional Applications & Engineering Value

This Grade 5 steel hex head screw delivers critical engineering value through its high-strength construction and zinc plated finish, specifically designed to address industrial fastening challenges. The 5/16"-18 UNC coarse threading provides superior resistance to vibration loosening while enabling rapid installation in structural steel, heavy machinery, and equipment manufacturing applications. The partially threaded design offers precise clamping force control, preventing joint distortion in critical assemblies. With external hex drive compatibility, maintenance teams can achieve proper torque values using standard tools, reducing installation time and ensuring consistent performance across production lines. The combination of 120,000 psi tensile strength and Rockwell C25 hardness makes this fastener ideal for applications requiring reliable performance under dynamic loads and harsh environmental conditions.

Specification Summary & Compliance

This 4" length hex head screw features precise Class 2A thread fit with UNC coarse threading (5/16"-18) and right-hand thread direction. Manufactured to ASME B18.2.1 and SAE J429 Grade 5 specifications, ensuring dimensional accuracy and mechanical properties. The fastener is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, meeting the latest industry standards for hazardous substance restrictions and chemical safety.