S-91251A658 5/16"-18 x 4 3/4" 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.
• Precise Class 3A thread fit provides superior engagement and vibration resistance, minimizing loosening in dynamic industrial environments.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable, non-reflective finish for extended service life.
• Hex socket drive design allows for high-torque installation with standard tools, enabling efficient assembly and maintenance in confined spaces.
• Partially threaded shank with coarse UNC threads ensures quick installation and secure clamping in a wide range of materials.
• Rockwell C37 hardness delivers excellent wear resistance, maintaining thread integrity and fastener performance over repeated use.
• Compliance with ASTM A574, RoHS 3, and REACH guarantees material consistency, environmental safety, and adherence to international industrial standards.

Professional Applications & Engineering Value

These Black-Oxide Alloy Steel Socket Head Cap Screws are engineered to address common challenges in heavy-duty industrial applications, such as machinery assembly, automotive components, and structural frameworks. The 5/16"-18 UNC coarse thread design facilitates rapid installation and provides strong holding power in metals and composites, reducing assembly time and labor costs. The hex drive and standard socket head profile enable secure tool engagement, preventing cam-out and ensuring consistent torque application in high-vibration environments. With a partially threaded rod type, these screws offer precise clamping control, minimizing stress concentration and enhancing joint reliability. Ideal for applications requiring high tensile strength and corrosion resistance, these fasteners deliver long-term performance in demanding conditions, supported by ASTM A574 certification for material quality and durability.

Specification Summary & Compliance

This product features a Class 3A thread fit for precise dimensional accuracy and superior thread engagement, adhering to UNC coarse thread standards. The manufacturing process complies with ASTM A574 specifications, ensuring consistent material properties and performance. Additionally, these screws are RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for hazardous substances. The combination of Rockwell C37 hardness and 170,000 psi tensile strength validates their suitability for high-stress industrial applications.