M3 Internal Tooth Lock Washer

Put on "protective clothing" for the M3 Internal Tooth Lock Washer. The core of the surface treatment is to enhance the corrosion resistance (i.e., rust prevention ability) of the washer, and sometimes it may also affect its conductivity.

（1）Zinc Plating

Feature:Good in terms of economy, with a silver-white or blue color, and widely used

Corrosion Resistance:Good (Medium)

（2）Dacromet / Zn-Al coating

Feature:No hydrogen embrittlement risk, excellent corrosion resistance, suitable for high-strength applications

Corrosion Resistance:Excellent (High)

（3）Black Oxide

Feature:Low cost, matte black appearance, limited rust prevention ability, usually requires oil coating for assistance

Corrosion Resistance:Poor (Low)

（4）Passivation

Feature:Stainless steel standard treatment enhances its own corrosion resistance and cleans the metal surface.

Corrosion Resistance:Excellent (High)

（5）Phosphate coating

Feature:It can be used as a coating base layer, or as an oil-containing anti-rust layer. However, its corrosion resistance is limited.

Corrosion Resistance: Average (Low)

Hydrogen Embrittlement: Electroplating (such as galvanizing) can make high-hardness steel (with hardness typically ≥ 360HV) brittle, posing a risk of fracture. For such high-strength M3 Internal Tooth Lock Washer, processes without hydrogen embrittlement risks, such as Dacromet or mechanical galvanizing, should be preferred.

FAQ

（1）Are M3 Internal Tooth Lock Washer with black oxide finish suitable for outdoor applications?

Not suitable. It turns black (oxidation to black color) and is almost not rust-resistant. It will rust outdoors very quickly.

（2）Can I get a black finish that also offers good corrosion protection?

Common - Darkened - Not very rust-resistant, not suitable for outdoor use. Recommended: Black zinc (black galvanization) or black Dacromet.

（3）What is the salt spray test hours for your standard zinc plated M3 Internal Tooth Lock Washer?

White zinc / blue zinc takes approximately 72 hours, while yellow zinc takes about 96 - 120 hours.

（4）Is Dacromet coating suitable for applications requiring electrical conductivity?

Not really. The Dacromet coating is insulating and it will obstruct the electrical path after the teeth engage.

（5）Does phosphating improve the anti-loosening effect?

It has an indirect positive effect. The phosphating layer has certain oil storage and lubricating properties, which makes the torque more stable during assembly.