S-91251A555 1/4"-20 x 3 1/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure
• Superior corrosion resistance from the black-oxide finish extends service life in demanding industrial environments
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections in critical applications
• Partially threaded design allows for optimal clamping force distribution and easier alignment during assembly
• Hex socket drive enables high-torque installation with standard tools, minimizing stripping and improving installation efficiency
• Coarse UNRC threading ensures quick assembly and superior holding power in various materials
• Rockwell C37 hardness maintains thread integrity and prevents deformation during repeated use

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws deliver exceptional engineering value in industrial applications where reliability is paramount. The combination of 170,000 psi tensile strength and Rockwell C37 hardness ensures these fasteners withstand extreme mechanical stresses without compromising performance. The Class 3A thread fit with coarse UNRC threading provides superior vibration resistance in machinery, automotive assemblies, and heavy equipment. The partially threaded design allows for precise clamping control while the hex socket drive accommodates high-torque applications without cam-out. These 1/4-20 socket head cap screws are engineered to solve common industrial challenges including joint integrity, corrosion resistance, and long-term durability in demanding environments.

Specification Summary & Compliance

Manufactured to ASTM A574 specifications with Class 3A thread fit precision and UNRC coarse thread standards. These socket head cap screws feature a 3/16" hex drive and right-hand thread direction with 1" minimum thread length. The fasteners are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use across industrial applications while meeting international quality standards.