S-91257A481 7/16"-20 x 6" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional load-bearing capacity with Grade 8 classification and 150,000 psi tensile strength for reliable performance in high-stress applications.
• Superior corrosion resistance from zinc yellow-chromate plating, extending service life in harsh industrial environments.
• Optimized torque transmission with external hex drive and 5/8" head width for secure installation using standard tools.
• Precise thread engagement through Class 2A thread fit and 7/16"-20 UNF fine threads, minimizing vibration loosening.
• Enhanced durability with Rockwell C33 hardness, maintaining structural integrity under repeated stress.
• Versatile partial threading allowing unthreaded shank sections for shear strength where needed.
• Regulatory compliance assurance meeting ASME B18.2.1, RoHS 3, and REACH standards for quality and environmental safety.

Professional Applications & Engineering Value

Engineered for demanding industrial scenarios, this Grade 8 hex head screw delivers critical reliability in heavy machinery, structural steel connections, and automotive assemblies where vibration resistance and 150,000 psi tensile strength are paramount. The zinc yellow-chromate plating provides a robust barrier against corrosion in outdoor or chemically exposed environments, while the 7/16"-20 UNF fine thread configuration ensures tighter clamping force and superior resistance to loosening compared to coarse threads. The partially threaded design offers optimal performance in applications requiring both threaded engagement and smooth shank bearing surfaces, making it an ideal heavy-duty fastener for construction equipment, manufacturing fixtures, and transportation infrastructure where failure is not an option.

Specification Summary & Compliance

This 6" hex head screw maintains precise Class 2A thread fit tolerances per UNF standards with 1 1/8" minimum thread length. Manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, it meets rigorous industrial standards for dimensional accuracy and mechanical properties. The fastener is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring adherence to environmental regulations regarding hazardous substances.