The Difference Between Hot-Dip Galvanizing and Electro-Galvanizing

Galvanizing is a process of zinc coating, with hot-dip galvanizing involving melting zinc and electro-galvanizing using an electrolytic method. While their manufacturing processes differ significantly, the final products may appear similar. So, how can we distinguish between hot-dip galvanizing and electro-galvanizing? Let's delve into it.


Firstly, Distinction in Processes:

Hot-dip galvanizing involves multiple processing steps, including oil removal, acid pickling, immersion in a flux bath, drying, and finally immersion in a molten zinc bath for a specific duration. On the other hand, electro-galvanizing, also known as zinc electroplating, utilizes an electrolytic process. After oil removal and acid pickling, the workpiece is immersed in a solution containing zinc salts. By connecting to the electrolytic equipment, zinc deposits onto the workpiece via directed movement of current between positive and negative poles.


Secondly, Differentiation in Appearance:

Hot-dip galvanized coatings tend to have a slightly rough appearance, often displaying process variations like ripples and dross, particularly noticeable at one end of the workpiece. The coating typically appears silver-white. In contrast, electro-galvanized coatings exhibit a smoother surface, predominantly in yellow-green tones, although variations like iridescence, pale blue-green, or white with a greenish tint can also occur. The workpiece generally does not show signs of dross or lumping.


In conclusion, understanding the distinctions between hot-dip galvanizing and electro-galvanizing is vital for selecting the most suitable coating process for your specific requirements.