S-91251A838 4-48 x 1 1/2" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance with black-oxide coating that protects against rust in demanding industrial environments
• Exceptional tensile strength of 170,000 psi ensures reliable performance under high-stress applications
• Precision Class 3A thread fit provides superior engagement and vibration resistance in critical assemblies
• Rockwell C37 hardness rating delivers excellent wear resistance and long-term durability
• Partially threaded design allows for optimal clamping force distribution and precise positioning
• Fine UNF thread spacing enables finer adjustments and better load distribution in thin materials
• Compact 3/32" hex drive facilitates installation in confined spaces while maintaining high torque capability

Professional Applications & Engineering Value

These 4-48 UNF socket head cap screws with black-oxide alloy steel construction address critical engineering challenges in precision manufacturing and heavy-duty applications. The combination of 170,000 psi tensile strength and Rockwell C37 hardness ensures reliable performance in high-vibration environments where fastener failure is not an option. The fine thread spacing provides superior holding power in thin-section materials commonly found in aerospace components, precision instruments, and electronic enclosures. The partially threaded design allows engineers to precisely control clamping force distribution, preventing material distortion while maintaining structural integrity. These industrial screws are particularly valuable in applications requiring repeated disassembly and reassembly, where the Class 3A thread fit maintains dimensional stability over multiple cycles.

Specification Summary & Compliance

This socket head cap screw features precision 4-48 UNF threads with Class 3A fit for exceptional dimensional accuracy and fine thread spacing for superior engagement. Manufactured to ASTM A574 specification, ensuring consistent quality and performance. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial applications with strict chemical substance restrictions.