S-91571A438 7/8"-9 x 4 1/2" ASME B18.2.6, ASTM A325, ASTM F3125 Medium-Strength Steel Heavy Hex Head Screws for Structural Applications
Medium-Strength Steel Heavy Hex Head Screws for Structural Applications
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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 120,000 psi tensile strength for demanding structural applications
- Superior durability and wear resistance thanks to Grade A325 steel construction and Rockwell C19 hardness
- Reliable fastening performance ensured by Class 2A thread fit and coarse UNC threading for easier assembly
- Optimized stress distribution through partial threading design with 3" grip length for enhanced joint integrity
- Easy installation and removal with external hex drive and 1 7/16" head width for standard tool compatibility
- Compliance with industry standards including ASME B18.2.6, ASTM A325, and ASTM F3125 for quality assurance
- Environmentally responsible manufacturing meeting RoHS 3 and REACH compliance requirements
Professional Applications & Engineering Value
This Grade A325 steel hex head screw delivers critical performance in structural steel connections, heavy machinery assembly, and construction applications where vibration resistance and structural integrity are paramount. The 7/8"-9 UNC coarse thread configuration provides superior holding power in steel-to-steel connections while resisting loosening under dynamic loads. Engineered with partial threading and substantial 3" grip length, this fastener concentrates thread engagement where needed most, preventing stress concentration at the thread run-out. The external hex drive design accommodates high-torque installation with standard tools, making it ideal for both field and factory applications requiring 120,000 psi tensile strength and reliable performance in demanding environments.
Specification Summary & Compliance
This hex head screw features precise Class 2A thread fit with 7/8"-9 UNC coarse threads and right-hand thread direction. Manufacturing complies with ASME B18.2.6, ASTM A325, and ASTM F3125 specifications, ensuring dimensional accuracy and mechanical properties. Environmental compliance includes RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) requirements, making this fastener suitable for regulated industrial markets.
