S-91251A034 1 1/2"-6 x 3" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance under extreme loads, reducing the risk of fastener failure in demanding applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life and maintaining integrity in harsh industrial environments.
• Precise Class 2A thread fit with coarse UNRC threads allows for faster assembly and secure fastening, minimizing cross-threading and improving installation efficiency.
• High hardness (Rockwell C37) provides excellent wear resistance, maintaining thread integrity and drive features through repeated use and high-stress conditions.
• Fully threaded design offers consistent clamping force along the entire 3" length, ideal for applications requiring uniform load distribution.
• Hex socket drive enables high-torque installation with standard tools, ensuring tight fastening in confined spaces without slippage.
• Compliance with ASTM A574, RoHS 3, and REACH standards guarantees material quality, environmental safety, and suitability for regulated industrial sectors.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in heavy-duty machinery, construction, and automotive assemblies where vibration, high stress, and environmental exposure are common. The coarse UNRC thread with Class 2A fit ensures quick, reliable engagement even in materials prone to debris buildup, reducing installation time and preventing thread stripping. Its high tensile strength and Rockwell C37 hardness provide durability against dynamic loads and abrasion, making it ideal for securing structural components, engine parts, and industrial equipment. The black-oxide surface treatment enhances corrosion resistance without sacrificing dimensional accuracy, offering long-term reliability in moist or chemically aggressive settings. By meeting ASTM A574 specifications, these screws deliver consistent performance for OEMs and maintenance teams requiring precision fasteners that withstand rigorous operational demands.

Specification Summary & Compliance

This socket head cap screw features a 1 1/2"-6 UNRC coarse thread with Class 2A tolerance for precise fit, a 3" fully threaded length, and is manufactured from alloy steel per ASTM A574 standards. It complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring adherence to environmental and safety requirements for industrial use.