S-91251A486 5/8"-18 x 3" 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.
• Superior corrosion resistance from the black-oxide finish on alloy steel extends service life and maintains integrity in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections, minimizing loosening in critical assemblies.
• High hardness rating (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive features through repeated use.
• 1/2" hex drive design allows for high torque application with standard tools, ensuring easy installation and removal without stripping.
• Partially threaded configuration enables optimal clamping force distribution, ideal for applications requiring precise grip length.
• Fine UNRF threads deliver enhanced holding power and better resistance to vibrational loosening compared to coarse threads.

Professional Applications & Engineering Value

Engineered for high-performance industrial applications, this black-oxide alloy steel socket head cap screw addresses critical engineering challenges in machinery, automotive, and heavy equipment sectors. The Class 3A UNRF fine thread configuration provides superior vibration resistance, preventing joint failure in dynamic load conditions. With 170,000 psi tensile strength and Rockwell C37 hardness, it withstands extreme mechanical stresses while the black-oxide surface treatment offers reliable corrosion protection without compromising dimensional accuracy. The partially threaded design allows for precise clamping in assemblies where full thread engagement isn't required, making it ideal for securing components in high-strength fastener applications requiring both durability and precision alignment.

Specification Summary & Compliance

This socket head cap screw features 5/8"-18 UNRF fine threads with Class 3A fit for precision threading applications. Manufactured to ASTM A574 specifications, it ensures consistent quality and performance. The product is RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting international environmental and safety standards for industrial use. Dimensions include 3" length with 1 3/4" minimum thread length and 1/2" hex drive size, manufactured in the inch system for compatibility with standard North American equipment and tooling.