This custom-made, cold-forged carbon steel, zinc-nickel alloy, black, oversized hexagonal self-tapping screw with a washer is a high-performance fastener. Its core features can be summarized as follows, balancing comprehensiveness with emphasis.
1. High-Strength Fastening and Load-Bearing
Material Properties: The carbon steel base provides high mechanical strength, while the cold-forging process enhances the continuity of the metal fibers, increasing tensile strength and shear resistance.
Structural Design: The hexagonal head facilitates high-torque installation, while the oversized washer distributes pressure and prevents loosening, making it suitable for use in vibrating environments.
2. Excellent Corrosion Resistance
Zinc-nickel alloy plating: Salt spray test resistance reaches 500-1000 hours, far exceeding the 72 hours of conventional galvanizing, and withstands harsh environments such as acid, alkali, and marine weather.
Black Passivation: A black oxide film forms on the zinc-nickel coating, providing both aesthetic appeal and rust protection.
3. Self-tapping and Quick Installation
Self-tapping thread design: Pre-drilled holes with sharp tip angles (25°-30°) cut directly into the metal/plastic substrate, eliminating the need for pre-tapping.
The cold-forming process increases thread density, ensuring smooth threading even after repeated assembly and disassembly.
4. Customizable Fit
Flexible Sizes: Customizable outer diameters, lengths, and washer thicknesses are available to accommodate unusual holes or specialized assembly spaces.
Surface Treatment Options: Adjustable plating thickness (8-15μm) and black color depths are available to meet diverse industry standards.
5. Application Scenarios
Typical Applications
Automotive: Sealing new energy battery cases to prevent electrolyte corrosion.
Power Equipment: Outdoor transformer fastening (weather resistance requirements).
Building Steel Structures: Attaching color-coated steel roofs (wind pressure resistance and waterproofing requirements).
