S-91257A611 5/16"-24 x 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 for reliable performance in high-stress applications
- Superior corrosion protection through zinc yellow-chromate plating that withstands harsh industrial environments
- Precise torque transmission enabled by external hex drive design and standard 1/2" head width
- Optimized thread engagement with UNF fine threading and Class 2A fit for vibration resistance
- Enhanced durability from Rockwell C33 hardness that maintains integrity under repeated use
- Versatile partial threading allowing both secure fastening and adjustable positioning
- Regulatory compliance assurance meeting ASME B18.2.1, SAE J429, RoHS 3, and REACH standards
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver critical performance where failure is not an option. The combination of 150,000 psi tensile strength and Rockwell C33 hardness provides exceptional resistance to shear and tensile forces in heavy machinery, construction equipment, and automotive assemblies. The zinc yellow-chromate plating creates a protective barrier against corrosion in outdoor or chemically aggressive environments, while the UNF fine threads maintain secure fastening under vibration. With partial threading and 2" length, these screws offer precise clamping force control in structural connections, making them ideal for demanding industrial fastening applications requiring both strength and corrosion resistance.
Specification Summary & Compliance
Manufactured to exacting standards with Class 2A thread fit tolerances and 5/16"-24 UNF fine thread specifications. These inch system fasteners comply with ASME B18.2.1 and SAE J429 manufacturing standards, ensuring dimensional accuracy and performance reliability. The products are fully RoHS 3 (2015/863/EU) compliant and REACH (EC 1907/2006) compliant, meeting the latest environmental and safety regulations for industrial components.
