S-91251A556 1/4"-20 x 3 1/2" 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 prolongs service life in harsh industrial environments.
- Precise Class 3A thread fit provides secure, vibration-resistant connections, minimizing loosening over time.
- High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated use.
- Hex socket drive design allows for easy installation and removal in confined spaces with standard tools.
- Partially threaded shank enables precise clamping force control, ideal for applications requiring specific grip lengths.
- Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency and environmental safety for global supply chains.
Professional Applications & Engineering Value
This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in heavy machinery, automotive assembly, and precision equipment manufacturing. The UNRC coarse thread and Class 3A fit provide superior resistance to vibrational loosening, while the high tensile strength and Rockwell C37 hardness ensure durability in dynamic load applications. The partially threaded design allows for optimal stress distribution, reducing the risk of thread stripping in soft materials. Ideal for use in industrial fastening systems requiring reliable, long-term performance under demanding conditions, this screw's corrosion-resistant black-oxide coating further enhances its suitability for outdoor or chemically exposed environments.
Specification Summary & Compliance
This socket head cap screw features a 1/4"-20 UNRC coarse thread with Class 3A tolerance for precise fit, a 3/16" hex drive, and a partially threaded shank with minimum thread length of 1". It is manufactured in compliance with ASTM A574 specifications for alloy steel socket head cap screws, ensuring consistent mechanical properties. The product is also RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting stringent environmental and safety regulations for industrial use.
