S-91257A573 1/4"-28 x 2 3/4" 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 industrial applications
- Superior corrosion protection through zinc yellow-chromate plating that withstands harsh environmental conditions
- Precise thread engagement with Class 2A UNF fine threads ensuring secure fastening and vibration resistance
- Optimal torque transmission via external hex drive design that prevents tool slippage during installation
- Enhanced durability from Rockwell C33 hardness rating that maintains structural integrity under repeated stress
- Versatile partial threading allowing both clamping and alignment functions in complex assemblies
- Regulatory compliance assurance meeting ASME, SAE, RoHS 3 and REACH standards for global industrial use
Professional Applications & Engineering Value
These Grade 8 hex head screws deliver critical engineering solutions where high tensile strength and corrosion resistance are paramount. The 1/4"-28 UNF fine threading provides superior vibration resistance in dynamic equipment, while the zinc yellow-chromate plating creates a protective barrier against chemical exposure and moisture in outdoor or industrial environments. The partially threaded design enables precise clamping force distribution across joint interfaces, making these steel fasteners ideal for heavy machinery, structural frameworks, and automotive assemblies where failure is not an option. With external hex drive compatibility, installation efficiency is maximized using standard industrial tools.
Specification Summary & Compliance
Manufactured to exacting Class 2A thread fit tolerances with UNF fine thread spacing per ASME B18.2.1 specifications. These Grade 8 hex head screws comply with SAE J429 mechanical properties and demonstrate full conformity to RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe usage across global industrial markets.
