S-91251A049 3/4"-16 x 3 1/2" 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 critical applications.
• Superior corrosion resistance from the black-oxide finish on alloy steel extends service life in harsh industrial environments, minimizing maintenance and replacement costs.
• Precision Class 3A thread fit with UNRF fine threads provides excellent vibration resistance and secure fastening, ideal for machinery and equipment subject to dynamic stresses.
• High hardness rating of Rockwell C37 offers excellent wear resistance, maintaining thread integrity and drive features through repeated use.
• Optimized drive engagement with the 5/8" hex socket allows for high torque application and easy installation in confined spaces, improving assembly efficiency.
• Partially threaded design combines the clamping force of threaded sections with the smooth shank for precise positioning and alignment in assemblies.
• Compliance with international standards including ASTM A574, RoHS 3, and REACH ensures material quality and environmental safety for global supply chain integration.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, these black-oxide alloy steel socket head cap screws address common challenges in heavy machinery, automotive, and aerospace sectors. The 3/4"-16 UNRF fine threads with Class 3A fit provide superior resistance to loosening under vibration, a critical factor in dynamic load environments. The partially threaded configuration allows for precise clamping without thread interference in clearance holes, simplifying assembly in structural frames and precision equipment. With a 170,000 psi tensile strength and Rockwell C37 hardness, these fasteners maintain integrity in high-stress applications, reducing downtime and maintenance costs. The black-oxide surface treatment enhances corrosion resistance without compromising dimensional accuracy, making them suitable for both indoor and outdoor industrial settings where environmental factors are a concern.

Specification Summary & Compliance

This socket head cap screw features precise Class 3A thread fit with UNRF fine threads (3/4"-16), ensuring tight tolerances for secure fastening. Manufacturing complies with ASTM A574 specification for high-strength alloy steel fasteners. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental and safety standards for industrial components.