S-91255A312 1/2"-13 x 3 1/2" ASTM F835 Steel Button Head Hex-Drive Screws

Key Features & Benefits at a Glance

• Exceptional corrosion resistance with black-oxide coating, ideal for harsh industrial environments
• Superior thread engagement and vibration resistance from UNC coarse threads with precise Class 3A fit
• High tensile strength of 120,000 psi ensures reliable performance under extreme mechanical loads
• Optimized torque transmission through 5/16" hex drive and rounded button head design
• Rockwell C39 hardness provides excellent wear resistance and durability
• Partial threading design allows for secure fastening in specific engagement zones
• Full compliance with major industry standards including ASME B18.3 and ASTM F835

Professional Applications & Engineering Value

This black-oxide alloy steel rounded head hex screw delivers critical performance advantages in demanding applications where corrosion resistance, high strength, and reliable fastening are paramount. The UNC coarse thread configuration with Class 3A thread fit ensures rapid assembly and superior vibration resistance in heavy machinery, construction equipment, and industrial assemblies. The combination of 120,000 psi tensile strength and Rockwell C39 hardness provides exceptional durability against mechanical stress and wear. The partially threaded design offers precise clamping control, making it ideal for applications requiring specific thread engagement zones while the 5/16" hex drive facilitates efficient installation in confined spaces.

Specification Summary & Compliance

Manufactured to precise dimensional standards with Class 3A thread fit tolerance and UNC coarse thread specifications. Complies with ASME B18.3 and ASTM F835 manufacturing standards. Meets environmental regulations including RoHS 3 (2015/863/EU) compliance and REACH (EC 1907/2006) requirements for hazardous substances.