S-91251A107 4-40 x 5/16" 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 on alloy steel, extending service life in demanding industrial environments.
- Precise Class 3A thread fit provides tighter tolerances for secure, vibration-resistant assemblies in critical applications.
- 3/32" hex drive design allows for easy installation and removal with standard tools, minimizing assembly time and effort.
- High hardness rating (Rockwell C37) enhances wear resistance, maintaining thread integrity through repeated use.
- Fully threaded UNC coarse threads enable faster installation and improved grip in a variety of materials.
- Compliance with ASTM A574, RoHS 3, and REACH guarantees material quality and environmental safety for global supply chains.
Professional Applications & Engineering Value
These 4-40 UNC thread socket head cap screws are engineered to address common industrial challenges such as vibration loosening and material fatigue. The black-oxide alloy steel construction provides a durable barrier against rust and corrosion, making them ideal for machinery, automotive, and electronics assemblies where exposure to oils or moisture is frequent. The coarse thread spacing and Class 3A thread fit ensure a secure, tight connection that resists back-out under dynamic loads, reducing maintenance needs. With a 170,000 PSI tensile strength and Rockwell C37 hardness, these screws deliver consistent performance in high-stress applications, from precision equipment to heavy-duty fixtures, ensuring long-term reliability and reduced downtime.
Specification Summary & Compliance
This product adheres to Class 3A thread fit for precise dimensional accuracy and UNC coarse thread standards. Manufacturing follows ASTM A574 specifications, ensuring high-quality alloy steel material. Compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting safe and sustainable industrial use.
