S-91251A820 5/8"-11 x 7" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress applications, 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 secure, vibration-resistant connections with minimal assembly issues
• Rockwell C37 hardness offers excellent wear resistance, maintaining thread integrity through repeated use
• 1/2" hex drive design allows for high-torque installation with standard tools, speeding up assembly processes
• Partially threaded shank enables optimal clamping force distribution where full threading isn't required
• Compliance with ASTM A574, RoHS 3 and REACH ensures material quality and environmental responsibility for global projects

Professional Applications & Engineering Value

Engineered for heavy-duty industrial applications, these black-oxide alloy steel socket head cap screws deliver exceptional mechanical properties where failure is not an option. The combination of 170,000 psi tensile strength and Rockwell C37 hardness makes them ideal for machinery, equipment manufacturing, and structural assemblies subjected to dynamic loads and vibration. The 5/8"-11 UNRC coarse thread with Class 3A precision ensures quick installation and reliable performance in steel-to-steel connections, while the black-oxide surface treatment provides essential corrosion protection in industrial environments. These socket head screws are particularly valuable in applications requiring flush mounting and high clamping forces, such as die sets, molds, and precision equipment where access is limited but performance cannot be compromised.

Specification Summary & Compliance

This 7" length socket head cap screw features 5/8"-11 UNRC coarse threads with Class 3A thread fit for precision assembly. The fastener meets ASTM A574 specification for alloy steel socket head cap screws and demonstrates compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations. Manufacturing follows inch system measurements with 1/2" hex drive, 15/16" head diameter, and minimum 1 3/4" thread length on the partially threaded design.