S-91251A637 3/8"-16 x 3 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.
• Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh industrial environments.
• Precise Class 3A thread fit guarantees tight tolerances and secure fastening, minimizing assembly errors and improving joint integrity.
• Partially threaded design allows for optimal clamping force distribution, ideal for applications requiring specific grip lengths.
• High hardness rating (Rockwell C37) provides excellent wear resistance, maintaining thread integrity through repeated use.
• Hex socket drive (5/16") enables easy installation with standard tools, reducing assembly time and enhancing workplace efficiency.
• Compliance with ASTM A574, RoHS 3, and REACH ensures material quality and environmental safety, meeting global regulatory standards.

Professional Applications & Engineering Value

Engineered for demanding industrial settings, these socket head cap screws in black-oxide alloy steel address critical challenges like vibration loosening and environmental degradation. The 3/8"-16 UNC coarse thread design ensures quick assembly and high load-bearing capacity, making them ideal for heavy machinery, automotive systems, and structural frameworks. With a partially threaded configuration, they provide focused clamping in precision equipment, reducing stress concentrations. The corrosion-resistant coating and high tensile strength deliver long-term reliability, minimizing maintenance downtime and costs in sectors such as aerospace, manufacturing, and construction.

Specification Summary & Compliance

This screw adheres to Class 3A thread fit for superior dimensional accuracy, with UNC coarse threads and a minimum thread length of 1 1/4". Manufactured under ASTM A574 specifications, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance for environmental safety, ensuring no hazardous substances are used. The Rockwell C37 hardness and precise head dimensions (9/16" diameter, 3/8" height) support consistent performance in regulated applications.