S-91247A366 1/2"-20 x 4 1/2" ASME B18.2.1, SAE J429 Medium-Strength Grade 5 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength: With 120,000 psi tensile strength, this screw provides reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior Corrosion Resistance: Zinc plating offers enhanced protection against rust and environmental elements, extending service life in demanding conditions.
• Precise Thread Engagement: Fine 1/2"-20 UNF threads with Class 2A fit ensure secure, vibration-resistant connections, minimizing loosening over time.
• High-Grade Material Durability: Made from Grade 5 steel with Rockwell C25 hardness, it withstands heavy loads and repetitive stress without deformation.
• Optimized for Easy Installation: External hex drive and 3/4" head width allow for straightforward tightening with standard tools, saving assembly time.
• Versatile Partial Threading: The partially threaded design provides strong clamping force where needed, ideal for applications requiring precise grip length.
• Regulatory Compliance Assurance: Meets ASME B18.2.1, SAE J429, RoHS 3, and REACH standards, ensuring safety and environmental responsibility in industrial use.

Professional Applications & Engineering Value

This Grade 5 steel hex head screw is engineered to address critical fastening challenges in heavy-duty industrial applications, such as machinery assembly, structural frameworks, and automotive components. The 1/2"-20 UNF fine threading and Class 2A thread fit deliver superior resistance to vibration and dynamic loads, preventing joint failure in high-stress environments. The zinc plating enhances corrosion resistance, making it suitable for outdoor or humid conditions without compromising integrity. With a 4 1/2" length and partial threading, it offers flexibility in clamping thick materials or assemblies where full threading isn't required. By combining 120,000 psi tensile strength and Rockwell C25 hardness, this fastener ensures long-term reliability, reducing maintenance needs and downtime in professional settings.

Specification Summary & Compliance

This screw adheres to precise dimensional standards, including Class 2A thread fit for consistent engagement and UNF fine threading with 1/2"-20 size. It complies with ASME B18.2.1 and SAE J429 specifications for quality and performance. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, ensuring it meets environmental and safety regulations for industrial use.