S-91251A160 4-40 x 1 3/4" 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 in critical assemblies.
- Corrosion-resistant black-oxide finish on alloy steel provides enhanced durability and longevity in demanding industrial environments.
- Precise Class 3A thread fit guarantees secure, vibration-resistant connections, minimizing loosening in machinery and equipment.
- Partially threaded design allows for optimal clamping force distribution, ideal for applications requiring precise joint control.
- Hex socket drive with 3/32" size enables easy installation in confined spaces using standard tools, improving assembly efficiency.
- High hardness (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated use and adjustments.
- Compliance with ASTM A574, RoHS 3, and REACH ensures material consistency, environmental safety, and suitability for regulated industries.
Professional Applications & Engineering Value
These black-oxide alloy steel socket head cap screws are engineered to address common industrial challenges, such as vibration-induced loosening and corrosion in harsh operating conditions. The 4-40 UNC coarse threads and Class 3A fit provide superior holding power in metal assemblies, machinery, and precision equipment, reducing maintenance needs. The partially threaded rod design concentrates clamping force where needed, preventing joint slippage. With a 170,000 psi tensile strength and corrosion-resistant coating, they excel in automotive, aerospace, and heavy machinery applications, ensuring long-term reliability and compliance with stringent industry standards like ASTM A574.
Specification Summary & Compliance
This screw features a 4-40 UNC coarse thread with Class 3A precision fit for tight tolerances, a length of 1-3/4", and a partially threaded shank. It meets ASTM A574 specifications for high-strength alloy steel fasteners and is compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material consistency in industrial use.
