S-91251A026 1 1/4"-12 x 4 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 industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish on alloy steel extends service life in demanding environments, minimizing maintenance needs.
• Precise thread engagement with Class 2A fit and UNRF fine threads provides secure, vibration-resistant connections for critical assemblies.
• High torque capability via the 7/8" hex drive and standard socket head design allows for easy installation and removal with standard tools.
• Optimized load distribution due to the partially threaded rod design and Rockwell C37 hardness enhances durability under dynamic loads.
• Regulatory compliance with ASTM A574, RoHS 3, and REACH standards ensures safety and environmental responsibility in global supply chains.
• Versatile inch sizing including 4 1/2" length and 1 1/4"-12 thread simplifies sourcing for machinery and equipment using imperial measurements.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address common industrial challenges such as vibration loosening and corrosion in heavy-duty equipment. The UNRF fine thread and Class 2A thread fit deliver precise, tight fastening that resists shock and fatigue, ideal for automotive, aerospace, and machinery assemblies where reliability is critical. The partially threaded design concentrates strength where needed, while the black-oxide surface treatment provides a durable barrier against moisture and chemicals, extending component life in harsh environments. With a 170,000 psi tensile strength and Rockwell C37 hardness, it supports high-load applications without compromising on reusability or safety.

Specification Summary & Compliance

This socket head cap screw adheres to inch measurement standards with a thread size of 1 1/4"-12, thread fit of Class 2A, and length of 4 1/2". It meets ASTM A574 specifications for high-strength fasteners and complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity for industrial use.