S-91251A437 1/4"-28 x 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 under high-stress conditions, reducing the risk of fastener failure in critical assemblies.
• Superior corrosion resistance from the black-oxide finish protects against rust and degradation, extending service life in harsh industrial environments.
• Precise Class 3A thread fit with fine UNRF threading provides tight, secure fastening with minimal backlash, ideal for applications requiring high vibration resistance.
• High hardness rating (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive engagement through repeated use.
• Compact socket head design with a 3/16" hex drive allows for easy installation in confined spaces while providing high torque capability.
• Full threading along the entire 1/2" length ensures maximum grip and uniform clamping force across the entire fastened joint.
• Compliance with ASTM A574 guarantees consistent quality and material properties, meeting rigorous industrial standards for socket head cap screws.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these black-oxide alloy steel socket head cap screws deliver exceptional durability and precision. The fine UNRF threading and Class 3A fit provide superior vibration resistance, making them ideal for machinery, automotive assemblies, and precision equipment where loosening under dynamic loads is a concern. The corrosion-resistant black-oxide coating ensures long-term reliability in environments exposed to moisture, chemicals, or temperature variations. With a 170,000 psi tensile strength and Rockwell C37 hardness, these fasteners withstand high stress and wear, reducing maintenance needs and downtime in continuous operation settings such as manufacturing lines, heavy equipment, and aerospace components.

Specification Summary & Compliance

This socket head cap screw features a 1/4"-28 thread size with Class 3A thread fit and fine thread spacing, ensuring precise dimensional accuracy per UNRF standards. Manufactured in compliance with ASTM A574 specifications, it meets stringent material and performance requirements. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, adhering to environmental and safety regulations for hazardous substances.