S-91251A120 1/2"-13 x 3 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 in high-stress industrial applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish prolongs service life in harsh environments, minimizing maintenance and replacement costs.
• Precise Class 3A thread fit provides consistent engagement and vibration resistance, enhancing assembly integrity and reducing loosening over time.
• Partially threaded design allows for secure clamping in specific zones, improving load distribution and simplifying installation in varied materials.
• High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity and drive features through repeated use.
• 3/8" hex drive compatibility enables easy installation with standard tools, speeding up assembly processes and reducing labor time.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material quality and environmental safety, supporting regulatory adherence in global supply chains.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address critical challenges in heavy-duty machinery, automotive, and construction sectors. The alloy steel construction, combined with a black-oxide surface treatment, provides robust protection against rust and oxidation, extending fastener lifespan in humid or corrosive conditions. Featuring a coarse UNRC thread and Class 3A fit, it ensures quick, secure fastening with minimal cross-threading risks, ideal for high-vibration environments like engine mounts or structural frames. The partially threaded rod design concentrates clamping force efficiently, preventing joint slippage in dynamic loads. By integrating high tensile strength and standardized hex drive compatibility, these screws streamline maintenance and reduce downtime, making them a cost-effective solution for demanding industrial applications.

Specification Summary & Compliance

This socket head cap screw adheres to precise dimensional standards, including a Class 3A thread fit for tight tolerances and a coarse UNRC thread with 1/2"-13 size. It meets ASTM A574 specifications for high-strength alloy steel fasteners, ensuring consistent manufacturing quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming the absence of hazardous substances and supporting environmentally responsible sourcing.