S-91251A603 1 1/4"-12 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, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh environments and minimizing maintenance needs.
• Precise fine thread design (UNRF 1 1/4"-12) provides enhanced clamping force and vibration resistance, ideal for critical assemblies.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive engagement over repeated use.
• Large 7/8" hex drive allows for high torque application with standard tools, speeding up installation in tight spaces.
• Partially threaded shank concentrates strength where needed and facilitates accurate positioning in structural joints.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material consistency and environmental safety, supporting global supply chain requirements.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common challenges in heavy-duty mechanical and industrial systems, such as vibration loosening and corrosion-induced degradation. The UNRF fine thread (1 1/4"-12) ensures a tight, secure fit in high-vibration environments like machinery, automotive assemblies, and construction equipment, reducing the need for frequent retightening. The alloy steel construction, combined with a black-oxide surface treatment, provides robust protection against rust and wear, making it suitable for outdoor or humid conditions. With a Class 2A thread fit and partially threaded design, it offers precise alignment and load distribution, enhancing the longevity and reliability of critical fastening points in demanding applications.

Specification Summary & Compliance

This socket head cap screw features a 1 1/4"-12 UNRF fine thread with Class 2A thread fit for consistent dimensional accuracy. It meets ASTM A574 specifications for high-strength alloy steel fasteners, ensuring material and manufacturing quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming it is free from hazardous substances and safe for industrial use worldwide.