S-91251A108 4-40 x 3/8" 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 provides reliable performance in high-stress applications, reducing the risk of fastener failure.
- Superior corrosion resistance from the black-oxide finish on alloy steel, extending service life in harsh industrial environments.
- Precise Class 3A thread fit ensures tight, secure fastening with minimal backlash, ideal for precision assemblies.
- Hex socket drive design allows for high torque application and easy installation in confined spaces, improving assembly efficiency.
- Coarse UNC threads enable quick engagement and reduced cross-threading, speeding up production and maintenance tasks.
- Full compliance with ASTM A574, RoHS 3, and REACH guarantees material consistency and environmental safety for global supply chains.
- Consistent hardness (Rockwell C37) and fully threaded shank offer uniform load distribution and enhanced grip strength.
Professional Applications & Engineering Value
This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in industrial settings, such as vibration resistance and corrosion in machinery, automotive, and aerospace components. The 4-40 UNC coarse thread and Class 3A fit provide reliable fastening in dynamic loads, while the hex drive facilitates secure installation with standard tools, minimizing downtime. Its high tensile strength and durable black-oxide surface treatment protect against wear and environmental factors, ensuring long-term performance in demanding applications like assembly jigs, engine parts, and electronic enclosures where precision and reliability are paramount.
Specification Summary & Compliance
This screw adheres to UNC thread standards with a Class 3A thread fit for precise dimensional accuracy. It meets ASTM A574 specifications for alloy steel socket head cap screws, ensuring material and manufacturing consistency. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, it supports environmental safety and global supply requirements.
