S-91251A298 1/4"-28 x 3 3/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating for extended service life in harsh environments
• Exceptional tensile strength of 170,000 PSI ensures reliable performance under high-stress conditions
• Precision Class 3A thread fit provides secure, vibration-resistant fastening with minimal play
• Fine UNF threading offers superior holding power and resistance to loosening in dynamic applications
• Hex socket drive design allows for high-torque installation in confined spaces with standard tools
• Partially threaded shank enables precise clamping force distribution across joint interfaces
• Full regulatory compliance with ASTM A574, RoHS 3, and REACH standards for global industrial use

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws deliver critical performance advantages in demanding assembly applications where corrosion resistance and high tensile strength are paramount. The UNF fine thread configuration combined with Class 3A precision thread fit ensures superior vibration resistance in machinery, automotive, and aerospace components where loosening under dynamic loads poses significant reliability concerns. The hex socket drive accommodates high installation torque while the partially threaded design provides optimal clamp load distribution, making these fasteners ideal for precision equipment, hydraulic systems, and heavy-duty industrial machinery requiring dependable, long-term fastening solutions.

Specification Summary & Compliance

Manufactured to exacting ASTM A574 specifications with Class 3A thread fit precision and UNF fine thread standards. Features include 1/4"-28 thread size, 3/16" hex drive, 3 3/4" length with minimum 1" thread engagement, and Rockwell C37 hardness rating. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations for global industrial applications.