S-91251A928 1"-8 x 6" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – With 170,000 psi tensile strength, this screw withstands extreme loads and vibrations, reducing the risk of failure in high-stress assemblies.
• Superior Corrosion Resistance – The black-oxide finish on alloy steel provides enhanced protection against rust and wear, extending service life in harsh environments.
• Precise Thread Fit – Class 3A thread fit ensures tight, secure fastening with minimal play, improving joint integrity and assembly accuracy.
• High Torque Capability – The 3/4" hex drive and standard socket head design allow for high torque application, facilitating quick and secure installation with common tools.
• Optimized for Heavy-Duty Use – Coarse UNRC threads and Rockwell C37 hardness offer excellent resistance to stripping and deformation, ideal for repetitive or high-load applications.
• Regulatory Compliance – Meets ASTM A574, RoHS 3, and REACH standards, ensuring material consistency and environmental safety for global industrial projects.
• Versatile Thread Design – Partially threaded shank with 2 1/2" min thread length provides flexibility in clamping and alignment, reducing the need for custom fasteners.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, this Black-Oxide Alloy Steel Socket Head Cap Screw addresses critical challenges in machinery, automotive, and construction assemblies. The coarse UNRC thread and Class 3A fit deliver reliable engagement in materials prone to vibration loosening, while the high tensile strength and Rockwell C37 hardness prevent shear and fatigue under dynamic loads. The black-oxide surface treatment enhances corrosion resistance without sacrificing dimensional stability, making it suitable for outdoor or humid environments. Its partially threaded design allows precise load distribution, minimizing stress concentration and simplifying maintenance in heavy-duty equipment and structural frameworks.

Specification Summary & Compliance

This socket head cap screw adheres to Class 3A thread fit and UNRC coarse thread standards, ensuring precise dimensional accuracy and interchangeability. Manufactured in accordance with ASTM A574 specifications, it guarantees material integrity and performance consistency. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting sustainable and safe industrial practices. All measurements follow the inch system, with a thread size of 1"-8 and a total length of 6".