S-91251A019 1/2"-20 x 2 1/4" 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.
• Superior wear resistance from Rockwell C37 hardness extends service life in demanding industrial environments.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant connections in critical assemblies.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance without compromising dimensional integrity.
• Fine UNF threads allow for better adjustment and holding power in precision applications compared to coarse threads.
• Hex socket drive design enables high torque application with standard tools, minimizing slip and tool wear.
• Partial threading provides unthreaded shank for improved shear strength and alignment in structured joints.

Professional Applications & Engineering Value

Engineered for high-strength fastening in machinery, automotive, and aerospace sectors, this socket head cap screw addresses common challenges like vibration loosening and material fatigue. The black-oxide alloy steel construction combats rust in humid or chemically exposed settings, while the fine UNF thread ensures precise engagement in tapped holes. Its 170,000 PSI tensile strength and Class 3A thread fit make it ideal for critical assemblies where reliability is paramount, reducing maintenance downtime and enhancing operational safety.

Specification Summary & Compliance

This screw adheres to inch system dimensions with a Class 3A thread fit for superior accuracy. It meets ASTM A574 specifications for high-strength bolts and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in regulated industries.