Non-standard cold forging carbon steel zinc-nickel alloy black enlarged meson washer hexagonal self-tapping screw is a high-performance fastener that combines special materials, processes, and designs for harsh working conditions. The following are its detailed usage and precautions.
1. Product characteristics and applicable scenarios
Material and process
Carbon steel matrix: high strength, cold forging to ensure structural density.
Zinc-nickel alloy plating + black passivation: corrosion resistance is better than ordinary galvanizing, and the black surface is both beautiful and anti-reflective.
Enlarged meson washer: increase the contact surface, disperse the pressure, prevent loosening or surface indentation of the workpiece.
External hexagonal head design: easy to apply force with a wrench or socket, and the torque transmission efficiency is higher than that of the internal hexagon.
Typical applications
Outdoor equipment that needs to be rust-proof and vibration-resistant.
Structural connection of thin sheet metal, plastic, or composite materials.
Black industrial products that require aesthetics (such as high-end home appliances and automotive interiors).
2. Usage steps and tips
1. Preparation before installation
Matching check:
Confirm the screw specifications and match the workpiece thickness. Self-tapping screws are suitable for soft materials with a thickness of ≤3mm.
Check whether the outer diameter of the washer covers the connection hole to avoid local stress concentration.
Tool selection:
Preferably use a torque wrench (refer to the manufacturer's data for the recommended value, usually 80% of the standard torque of carbon steel self-tapping screws).
When installing manually, you can use an external hexagonal socket or an open-end wrench to avoid slipping caused by using an adjustable wrench.
2. Installation process
Step 1: Positioning and pre-tightening
Align the screw vertically to the workpiece, lightly press the washer against the surface, and manually screw it in 2-3 turns to ensure thread engagement.
Note: It is recommended to pre-drill hard materials (such as stainless steel) with a hole diameter of 70%-90% of the screw diameter.
Step 2: Final tightening
Use the tool to tighten at a uniform speed until the washer is completely flattened and slightly elastically deformed.
Key point: The zinc-nickel alloy coating is harder, so avoid repeated disassembly to prevent thread wear.
3. Anti-loosening measures
Nylon gaskets or thread glue can be used in vibration environments, but attention should be paid to the compatibility of the glue with the zinc-nickel plating.
Regularly inspect the gasket to see if the preload is reduced due to creep.
III. Precautions
Corrosion protection
The black passivation layer is not resistant to strong acids and alkalis, so avoid using it in chemical environments or contact with rust removers.
It is recommended to apply anti-rust oil in marine environments.
Strength limit
The hardness of carbon steel self-tapping screws is usually HRC 22-32, which is not suitable for ultra-high-strength connections.
Failure treatment
If the thread is slipped, it is necessary to replace the screw with a larger diameter or use a thread insert to repair it.
IV. Maintenance suggestions
Wipe with a soft cloth when cleaning, and do not use a steel ball to scratch the coating.
Store in a dry environment to prevent the coating from oxidizing and turning white.
Through standardized operation and scene adaptation, the screw can significantly improve the connection reliability and life. For special working conditions, it is recommended to consult the manufacturer for customized verification.
