S-91274A220 1/4"-20 x 3 3/4" ASME B18.3, ASTM A574, ASTM B117 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance provided by the zinc-flake coating extends service life in harsh industrial environments.
• Precise Class 3A thread fit guarantees secure, vibration-resistant connections with minimal loosening over time.
• High hardness (Rockwell C37) enhances wear resistance and durability under repetitive loading conditions.
• Partially threaded design allows for optimal clamping force distribution and easier alignment during assembly.
• ASME B18.3 compliance ensures consistent quality and interchangeability with standard components.
• Hex socket drive enables high-torque installation in confined spaces without slipping.

Professional Applications & Engineering Value

This zinc-flake-coated alloy steel socket head cap screw is engineered to address critical challenges in heavy machinery, automotive, and construction sectors. Its UNC coarse thread and Class 3A fit provide exceptional grip and vibration resistance, preventing joint failure in dynamic loads. The partially threaded shank concentrates clamping force precisely where needed, reducing stress concentration. With a 170,000 psi tensile strength and corrosion-resistant coating, it outperforms standard fasteners in aggressive environments, minimizing maintenance downtime and ensuring long-term structural integrity for industrial assemblies.

Specification Summary & Compliance

This screw meets ASME B18.3 and ASTM A574 specifications, with precise Class 3A thread fit and UNC coarse threading for consistent performance. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental and safety standards are met for industrial use.