S-91251A510 5/8"-18 x 6 1/2" 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 on alloy steel extends service life in harsh industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies in critical machinery.
• Fine thread spacing (UNF) offers improved adjustment accuracy and better load distribution compared to coarse threads.
• High hardness (Rockwell C37) enhances wear resistance, maintaining thread integrity through repeated use and disassembly.
• Partially threaded design allows for controlled clamping force and reduced risk of cross-threading during installation.
• 1/2" hex drive compatibility enables easy installation and removal with standard tools, speeding up assembly processes.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, these black-oxide alloy steel socket head cap screws address common challenges like vibration loosening and material fatigue. The UNF fine thread configuration ensures superior holding power in precision equipment, automotive assemblies, and heavy machinery where alignment and stability are critical. The Class 3A thread fit minimizes backlash, enhancing safety in dynamic load conditions. With a Rockwell C37 hardness and robust 170,000 psi tensile strength, these screws withstand extreme forces without deformation, making them ideal for construction, aerospace, and manufacturing applications requiring durable, high-performance industrial fasteners.

Specification Summary & Compliance

This socket head cap screw adheres to Class 3A thread fit for inch-series UNF threads, ensuring precise dimensional accuracy. Manufactured in compliance with ASTM A574 specifications, it meets rigorous quality standards for alloy steel fasteners. The product is confirmed RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, supporting environmentally responsible sourcing and usage in global industrial markets.