S-91251A219 5-40 x 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 protects against rust and degradation in harsh industrial environments.
- Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies with minimal play.
- High hardness rating (Rockwell C37) enhances wear resistance and extends service life in demanding applications.
- Partially threaded design allows for controlled clamping force and easier alignment in precision assemblies.
- Coarse UNC thread spacing enables quicker installation and reduced cross-threading risks compared to fine threads.
- Standard hex socket drive (3/32") offers high torque capability and secure tool engagement in confined spaces.
Professional Applications & Engineering Value
These Black-Oxide Alloy Steel socket head cap screws are engineered to address critical challenges in industrial fastening, such as vibration loosening and environmental corrosion. The 5-40 UNC coarse thread design ensures rapid assembly in materials like cast iron and soft metals, while the Class 3A fit maintains precise alignment in machinery, automotive, and aerospace components. With a minimum thread length of 3/4" and partially threaded shank, these screws provide optimal grip without over-penetration, making them ideal for securing engine parts, jigs, and heavy-duty equipment where reliability and 170,000 psi tensile strength are non-negotiable.
Specification Summary & Compliance
This product adheres to Class 3A thread fit tolerances per UNC standards, ensuring dimensional accuracy for consistent performance. Manufacturing complies with ASTM A574 specifications for alloy steel socket head cap screws. The screws are confirmed RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, meeting environmental and safety regulations for industrial use.
