The advantages and disadvantages of electrogalvanizing and hot-dip galvanizing primarily focus on coating properties, application scenarios, and cost-effectiveness. 

Hot-dip galvanizing offers greater corrosion resistance and durability, but is more expensive. 

Electrogalvanizing, on the other hand, is more suitable for precision parts processing and offers a more aesthetically pleasing appearance.

Definition and Process Differences

Electrogalvanizing (cold galvanizing).

A 5-30μm zinc layer is deposited on the metal surface through electrolytic deposition, with the process temperature controlled at 20-40°C.

Process flow: Degreasing → Pickling → Electroplating → Passivation → Drying; no high-temperature treatment is required.

Hot-dip galvanizing (hot-dip galvanizing).

The workpiece is immersed in molten zinc at 460-480°C, forming a 50-200μm alloy coating consisting of both pure zinc and zinc-iron alloy layers.

Key steps: Degreasing → Pickling → Fluxing → Galvanizing → Cooling. The zinc solution consumption is approximately 40-60kg per ton of steel. ‌

Core Performance Comparison‌

Corrosion Resistance.

Hot-dip galvanizing: Outdoor service life can reach 50 years (marine environment) to 30 years (urban environment), and the zinc layer still provides electrochemical protection even after damage. ‌

Electrogalvanizing: Rust protection period is approximately 2-5 years indoors, but pitting corrosion is more likely to occur in humid environments. ‌

Economical Efficiency.

The cost per unit of hot-dip galvanizing is approximately 3-5 times that of electrogalvanizing, but the overall lifecycle cost is lower. ‌

Physical Properties.

Adhesion: Hot-dip galvanizing has a bond strength of >30 MPa (metallurgical bond), while electrogalvanizing is only 5-10 MPa (physical bond). ‌

Surface Quality: Electrogalvanizing has a surface roughness of Ra ≤ 0.8 μm, while hot-dip galvanizing has a Ra ≥ 1.6 μm. ‌

Typical Applications‌

Hot-dip galvanizing's advantages.

Transmission towers (annual usage exceeds 2 million tons). Highway guardrails (coating thickness ≥ 85μm).

Ship anchor chains (must pass a 4000-hour salt spray test).

Electrogalvanizing applications.

Precision hardware (such as screws and nuts, tolerance ±0.1mm).

Electronic product casings (surface gloss ≥ 80GU).

Automotive interior parts (requires subsequent painting).