S-91251A037 1/2"-20 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 under high-stress conditions, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in industrial environments and minimizing maintenance needs.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, enhancing joint integrity in machinery and equipment.
• 3/8" hex drive design allows for high-torque installation with standard tools, improving assembly efficiency and reducing stripping risks.
• Fine UNRF thread profile offers improved load distribution and better sealing capabilities compared to coarse threads, ideal for precision engineering applications.
• Partially threaded shank enables accurate clamping force control, preventing thread damage in soft materials and simplifying alignment in complex assemblies.
• Full compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and global regulatory acceptance for cross-border projects.

Professional Applications & Engineering Value

Engineered for high-stress industrial applications, this black-oxide alloy steel socket head cap screw solves critical challenges in machinery assembly, automotive systems, and heavy equipment manufacturing. The Class 3A UNRF fine thread maintains clamping force under vibration, while the Rockwell C37 hardness resists wear in dynamic load environments. Its partially threaded design concentrates stress away from shear planes, making it ideal for precision jigs, hydraulic components, and structural frames where 170,000 psi tensile strength prevents joint loosening. The black-oxide surface treatment provides consistent friction coefficients for accurate torque values, reducing installation errors in automated production lines.

Specification Summary & Compliance

This socket head cap screw maintains Class 3A thread fit per UNRF standards with a minimum thread length of 1-1/2" and 0.5" thread diameter. Manufactured to ASTM A574 specifications for alloy steel socket head cap screws, it guarantees dimensional consistency and mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and unrestricted use in global industrial supply chains.