Fractional Size Socket Head Cap Screws with Thermal Black Oxide Plating
Socket Head Cap Screws with Thermal Black Oxide Finish
Socket Head Cap Screws manufactured to ASME B18.3 standards and produced from ASTM A574 alloy steel are engineered for extreme strength, precision, and durability. These high-performance fasteners are designed for demanding mechanical and industrial applications where high clamp loads, limited clearance, and reliable torque transmission are required.
High-Strength Alloy Steel Performance
ASTM A574 socket head cap screws are heat-treated alloy steel fasteners built to handle severe stress and dynamic loads. For diameters less than 1/2 inch, these screws provide a minimum tensile strength of 180,000 psi, a proof load of 140,000 psi, and a Rockwell hardness of HRC 39–44. Sizes greater than 1/2 inch deliver a minimum tensile strength of 170,000 psi, a proof load of 135,000 psi, and a Rockwell hardness of HRC 37–44. This strength profile makes them ideal for high-load and vibration-prone assemblies.
Thermal Black Oxide Alloy Plating Benefits
Thermal black oxide plating is applied to enhance surface durability while maintaining precise dimensional tolerances. This process creates a uniform, matte black finish that improves resistance to wear, oxidation, and mild corrosion. Unlike thicker coatings, black oxide does not interfere with thread fit, making it ideal for precision fastening applications. The finish also provides a professional appearance and improved lubricity during installation.
Socket Head Design for Maximum Torque
The cylindrical head with internal hex drive allows for significantly higher torque application compared to traditional external-drive fasteners. This design minimizes the risk of stripping and enables secure fastening in tight or recessed spaces where wrench clearance is limited. Fractional sizing ensures compatibility with imperial-based machinery and equipment.
Common Applications Across Industries
Aerospace and defense assemblies
Automotive engines and drivetrains
Industrial machinery and tooling
Electronics and precision equipment
Key Advantages of Black Oxide Socket Head Cap Screws
Extremely high tensile and proof load strength
ASTM A574 alloy steel construction
Thermal black oxide finish for wear and corrosion resistance
Compact socket head design for tight spaces
Fractional sizing for U.S. standard applications
Socket head cap screws with thermal black oxide alloy plating deliver unmatched strength, precision, and reliability for critical fastening applications where performance cannot be compromised.