S-91500A554 1/4"-20 x 3" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws

Key Features & Benefits at a Glance

• Superior corrosion resistance in harsh environments thanks to 316 stainless steel construction with passivated finish
• Exceptional mechanical strength with 70,000 psi tensile strength and Rockwell B80 hardness for reliable load-bearing performance
• Optimized installation efficiency with Phillips No. 3 drive and standard flat head profile for flush mounting
• Secure coarse thread engagement through UNC 1/4"-20 threading with Class 2A fit for vibration resistance
• Versatile partial threading design allowing both secure fastening and alignment flexibility in assemblies
• Industry-standard compliance meeting ASME B18.6.3 specifications for dimensional accuracy and performance
• Environmental regulation adherence with RoHS 3 and REACH compliance for global industrial applications

Professional Applications & Engineering Value

Engineered for demanding industrial environments, these 316 stainless steel flat head screws provide critical corrosion resistance in chemical processing, marine, and food-grade applications where moisture and corrosive agents degrade ordinary fasteners. The partially threaded design combines the holding power of engaged threads with the alignment benefits of an unthreaded shank, while the 82° countersink angle ensures flush mounting in precision assemblies. With UNC coarse threads maintaining grip under vibration and the passivated finish enhancing surface durability, these Phillips flat head screws deliver long-term reliability in structural frameworks, machinery guards, and equipment housings where fastener failure is not an option.

Specification Summary & Compliance

This 1/4"-20 x 3" flat head screw features Class 2A thread fit per ASME B18.6.3 standards, ensuring precise dimensional tolerances for consistent performance. Manufacturing complies with ASME B18.6.3 specifications for flat head screw geometry and mechanical properties. The product is fully RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting international environmental regulations for hazardous substance restrictions.