S-90044A426 1/4"-20 x 2 5/8" ASME B18.3, 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 extends service life in harsh industrial environments, minimizing maintenance needs.
• Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies, enhancing joint integrity.
• Partially threaded design allows for optimal clamp force distribution, preventing loosening in dynamic or loaded structures.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated installation and removal cycles.
• Hex socket drive enables easy installation in confined spaces with standard tools, improving assembly efficiency and reducing labor time.
• Coarse UNRC threads facilitate quicker installation and better performance in materials like cast iron or soft metals, speeding up production processes.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in industrial fastening, such as vibration-induced loosening and environmental degradation. The 1/4-20 thread size with coarse spacing and Class 3A fit ensures rapid, secure engagement in machinery, automotive assemblies, and structural frameworks, reducing downtime from fastener failures. Its partial threading concentrates clamping force near the head, ideal for precision equipment where alignment stability is paramount. The black-oxide surface treatment provides a durable barrier against moisture and chemicals, making it suitable for outdoor or corrosive settings like marine or manufacturing plants. By combining high tensile strength with compliance to ASME B18.3, this screw delivers consistent performance in heavy-duty applications, from conveyor systems to robotics, ensuring long-term reliability and safety.

Specification Summary & Compliance

This socket head cap screw adheres to ASME B18.3 specifications with material standards per ASTM A574, ensuring dimensional accuracy and Class 3A thread fit for precise assembly. It features a coarse UNRC thread with a minimum thread length of 1 inch and a right-hand direction. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing environmental safety and restricted substance-free manufacturing for global industrial use.