S-91257A443 5/16"-24 x 4 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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Key Features & Benefits at a Glance
- Exceptional load-bearing capacity with 150,000 psi tensile strength, ideal for high-stress industrial applications
- Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments
- Reliable thread engagement through Class 2A thread fit and UNF fine threading, ensuring vibration resistance and secure fastening
- Optimized torque transmission via external hex drive design, allowing for efficient installation with standard tools
- Enhanced durability from Rockwell C33 hardness, maintaining structural integrity under repeated stress
- Versatile partial threading enabling precise clamping force distribution across connected components
- Regulatory compliance assurance meeting ASME, SAE, RoHS 3, and REACH standards for quality and environmental safety
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver critical performance in demanding industrial fastening scenarios where failure is not an option. The combination of high-strength steel material and 5/16"-24 UNF fine threading provides superior resistance to vibrational loosening in machinery, construction equipment, and structural assemblies. The zinc yellow-chromate plating offers enhanced corrosion protection, making these fasteners suitable for outdoor applications or environments with exposure to moisture and chemicals. The partially threaded design allows for precise clamping force concentration where needed, while the external hex drive ensures compatibility with standard wrenching tools for efficient installation and maintenance operations.
Specification Summary & Compliance
This 4 1/2" length hex head screw features precise Class 2A thread fit with 5/16"-24 UNF fine threading and 7/8" minimum thread length. Manufactured to ASME B18.2.1 and SAE J429 specifications, ensuring dimensional accuracy and mechanical performance. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, guaranteeing safe use across various industrial sectors.
