S-91251A490 5/8"-18 x 5" 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 industrial applications, preventing fastener failure.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies with minimal backlash.
• Fine UNRF thread design offers improved load distribution and better sealing capabilities compared to coarse threads.
• High hardness (Rockwell C37) enhances wear resistance, maintaining thread integrity through repeated use.
• 1/2" hex drive compatibility allows for high-torque installation with standard industrial tools.
• Partial threading enables precise clamping force control where full thread engagement isn't required.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw delivers critical performance advantages for demanding industrial applications. The combination of 170,000 psi tensile strength and Rockwell C37 hardness provides exceptional resistance to mechanical stress and wear in heavy machinery, automotive assemblies, and precision equipment. The fine UNRF thread with Class 3A fit ensures vibration resistance in dynamic applications while maintaining precise alignment. The black-oxide surface treatment creates a protective barrier against corrosion without significantly increasing dimensions, making it ideal for environments where moisture or chemicals are present. These socket head cap screws are engineered to solve common industrial challenges including joint relaxation, thread stripping, and corrosion-induced failure.

Specification Summary & Compliance

This fastener features 5/8"-18 UNRF fine threads with Class 3A thread fit for precision engagement, manufactured to ASTM A574 specifications for high-strength socket head cap screws. The product maintains dimensional accuracy with a 1/2" hex drive, 15/16" head diameter, and 5" overall length with 1 3/4" minimum thread length. Compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring suitability for various industrial sectors with strict material restrictions.