S-91251A439 1/4"-28 x 5/8" ASTM A574 Alloy Steel Socket Head Screws
Alloy Steel Socket 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 tensile strength of 170,000 psi ensures reliable performance under high-stress conditions, reducing the risk of fastener failure.
- Superior corrosion resistance from the black-oxide finish extends service life in harsh or humid industrial environments.
- Precision Class 3A thread fit provides tighter tolerances for secure, vibration-resistant fastening in critical assemblies.
- Fine UNRF threads offer improved load distribution and better sealing capabilities compared to coarse threads.
- Hex socket drive design allows for high torque application and easy installation in confined spaces with standard tools.
- Full threading along the 5/8" length enables adjustable positioning and consistent clamping force across the entire fastener.
- Rockwell C37 hardness maintains dimensional stability and wear resistance through repeated use and disassembly.
Professional Applications & Engineering Value
This black-oxide alloy steel socket head cap screw is engineered to address common industrial challenges such as vibration loosening, corrosion-induced degradation, and precision alignment requirements. The Class 3A UNRF fine threads create a secure, tight fit that minimizes backlash in machinery, automotive, and aerospace assemblies where dimensional accuracy is critical. The hex drive socket facilitates easy installation with standard Allen wrenches, even in limited-access areas. Combined with its high tensile strength and corrosion-resistant coating, this fastener delivers long-term reliability in demanding applications including precision equipment, hydraulic systems, and structural frameworks that require consistent clamping force and resistance to environmental factors.
Specification Summary & Compliance
This socket head cap screw features 1/4"-28 UNRF fine threads with Class 3A fit for precision tolerance, a 5/8" fully threaded length, and 3/16" hex drive. Manufactured to ASTM A574 specification for alloy steel socket head cap screws, it meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance standards for environmental safety and restricted substances.
