S-91251A450 1/4"-28 x 2" 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 in demanding applications.
• Precise Class 3A thread fit provides superior engagement and vibration resistance, minimizing loosening in critical assemblies.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable, non-reflective finish for extended service life.
• Fine UNRF threads deliver improved clamping force and better sealing capabilities compared to coarse threads.
• Partially threaded design allows for precise clamping control and reduced risk of cross-threading during installation.
• 3/16" hex drive socket head enables high-torque installation with standard tools, ensuring secure fastening in confined spaces.
• Rockwell C37 hardness provides excellent wear resistance and maintains thread integrity through repeated use.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws with 1/4"-28 UNRF fine threads are engineered to address common industrial fastening challenges. The Class 3A thread fit ensures precise alignment and superior vibration resistance in machinery, automotive, and aerospace applications where reliability is critical. The partially threaded configuration prevents binding and allows for accurate positioning in assemblies requiring specific clamp load distribution. With 170,000 psi tensile strength and Rockwell C37 hardness, these screws maintain structural integrity in high-stress environments while the black-oxide surface treatment provides corrosion protection without compromising dimensional accuracy. The 3/16" hex drive facilitates efficient installation in limited-access applications, making them ideal for precision equipment, manufacturing fixtures, and heavy-duty industrial machinery.

Specification Summary & Compliance

These socket head cap screws feature 1/4"-28 UNRF fine threads with Class 3A thread fit for precision engagement. Manufactured to ASTM A574 specifications with Rockwell C37 hardness and 170,000 psi tensile strength. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. The inch system measurements ensure compatibility with standard industrial equipment and replacement parts.