S-91251A959 7/16"-20 x 2 1/4" 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 demanding applications.
• Enhanced corrosion resistance from the black-oxide finish prolongs service life in harsh industrial environments, minimizing maintenance and replacement costs.
• Precise Class 3A thread fit provides superior engagement and vibration resistance, ideal for assemblies requiring tight tolerances and stability.
• Fine thread spacing offers improved clamping force and better load distribution compared to coarse threads, enhancing joint integrity.
• High hardness rating (Rockwell C37) increases wear resistance and durability, ensuring long-term performance in repetitive or high-load scenarios.
• Partially threaded design allows for controlled clamping and easier alignment in precision machinery and equipment setups.
• Standard hex drive (3/8") enables quick and secure installation with common tools, boosting assembly efficiency and reducing labor time.

Professional Applications & Engineering Value

This Black-Oxide Alloy Steel Socket Head Cap Screw is engineered to address critical challenges in industrial settings, such as vibration-induced loosening and corrosion in aggressive environments. The UNRF fine thread and Class 3A fit ensure minimal backlash and superior holding power, making it ideal for precision machinery, automotive assemblies, and heavy-duty equipment where reliability is paramount. The high tensile strength and Rockwell C37 hardness provide resilience against dynamic loads and wear, while the black-oxide surface treatment offers added protection against moisture and chemicals. By integrating these features, this fastener delivers consistent performance in applications requiring corrosion resistance, dimensional accuracy, and long-term durability, reducing downtime and maintenance efforts for B2B users.

Specification Summary & Compliance

This socket head cap screw adheres to ASTM A574 specifications, ensuring consistent quality and performance. It features a Class 3A thread fit for precise tolerance and a UNRF fine thread with a size of 7/16"-20. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its safety and environmental standards for global industrial use.