S-91251A469 1/4"-28 x 4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior tensile strength of 170,000 psi ensures reliable performance under extreme loads, reducing the risk of fastener failure in demanding applications.
• Exceptional hardness (Rockwell C37) provides excellent wear resistance and durability, extending the service life of the screw in high-stress environments.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance, protecting against rust and degradation in various industrial conditions.
• Precision Class 3A thread fit guarantees tight tolerances and secure fastening, minimizing backlash and improving assembly accuracy.
• Fine UNF threads allow for finer adjustments and higher clamping force in applications where vibration resistance is critical.
• Hex socket drive (3/16") enables easy installation with standard tools, providing high torque transmission and reducing the chance of stripping.
• Compliance with ASTM A574, RoHS 3, and REACH ensures the screw meets rigorous industry standards for quality and environmental safety, supporting responsible sourcing.

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 machinery assemblies. The fine UNF thread design enhances grip in precision equipment, while the Class 3A thread fit ensures minimal play for stable connections in automotive, aerospace, and heavy machinery applications. Made from high-strength alloy steel with a protective black-oxide finish, it resists environmental wear and reduces maintenance needs. Ideal for partially threaded configurations, it provides reliable fastening in dynamic loads, helping engineers achieve long-term reliability and compliance with ASTM A574 specifications.

Specification Summary & Compliance

This screw features a 1/4"-28 UNF fine thread with a Class 3A thread fit for high precision, a length of 4", and a partially threaded rod type. It complies with ASTM A574 manufacturing standards, ensuring consistent quality and performance. Additionally, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its environmental and safety compliance for global industrial use.