S-91251A593 5/16"-18 x 2 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.
• Class 3A thread fit provides tighter tolerances for superior fastening precision and vibration resistance in demanding applications.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance and a durable, non-reflective finish for long-lasting use.
• Partially threaded design allows for precise clamping force control and secure fastening in assemblies requiring unthreaded shank sections.
• Coarse UNC threads enable quick and easy installation, reducing assembly time and improving efficiency in industrial settings.
• Rockwell C37 hardness ensures high wear resistance and durability, maintaining integrity through repeated use.
• 1/4" hex drive socket head facilitates easy access and high torque application with standard tools, minimizing slippage and damage.

Professional Applications & Engineering Value

These black-oxide alloy steel socket head cap screws are engineered to address critical challenges in heavy-duty industrial environments, such as machinery, automotive, and construction assemblies. The UNC coarse thread design ensures rapid installation and robust holding power, while the partial threading provides optimal grip in materials prone to stress concentration. With a 170,000 psi tensile strength and Rockwell C37 hardness, these screws resist deformation and fatigue under dynamic loads, making them ideal for applications requiring high reliability. The black-oxide surface treatment adds a layer of corrosion protection, extending service life in harsh conditions without compromising on the sleek, low-profile socket head that allows for compact designs and easy maintenance.

Specification Summary & Compliance

This product adheres to Class 3A thread fit for precise dimensional accuracy and meets ASTM A574 specifications, ensuring consistent quality and performance. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmentally responsible and safe industrial use. The screw features a 5/16"-18 UNC coarse thread with a minimum thread length of 1-1/8" and a total length of 2-1/2", designed for reliable fastening in various engineering applications.