What is the difference of Hot-dip galvanizing and electric galvanizing?

What is the difference of Hot-dip galvanizing and electric galvanizing?

Hot-dip galvanizing and electro-galvanizing are both processes for applying a zinc coating to steel or iron to protect it from corrosion, but they differ significantly in application methods, coating thickness, durability, and typical applications. Here's a breakdown of each:

1. Hot-Dip Galvanizing (HDG)

• Process: The steel is dipped in a bath of molten zinc at around 450°C (842°F), which creates a strong metallurgical bond between zinc and the steel.
• Coating Thickness: HDG creates a thick zinc coating, usually between 50-100 microns (µm) or more, depending on the steel's thickness and surface preparation.
• Durability: This thicker layer provides excellent corrosion resistance, making it more suitable for long-term, outdoor applications.
• Appearance: HDG results in a rougher, dull, matte-gray finish, which may develop a patina over time.
• Typical Uses: Ideal for outdoor structures exposed to harsh weather, such as utility poles, guard rails, and electrical conduit systems.

RIFI Hot dip galvanized finish items for example  :

RIFI Hot dip galvanized strut channel 

RIFI Hot dip galvanized EMT conduit UL listed

RIFI BS4568 BS EN 61386 GI conduit 

2. Electro-Galvanizing (EG)

• Process: Electro-galvanizing, or electroplating, applies zinc by passing an electric current through a zinc solution, creating a thin, even coating.
• Coating Thickness: The zinc layer is generally thin, ranging from 5-30 microns (µm), depending on the application.
• Durability: Although it offers some corrosion resistance, it’s less durable than HDG, making it more suitable for indoor or mild environments.
• Appearance: EG has a smooth, bright, and shiny finish, preferred for aesthetic applications.
• Typical Uses: Common for indoor items, decorative parts, automotive bodies, and small fasteners and accessories .

RIFI Hot dip galvanized finish items for example :

RIFI electro galvanized EMT conduit fittings - EMT conduit steel  connector and coupling 

RIFI EMT one hole strap , 2 hole strap  electro galvanized . 

Summary Comparison

Each method is chosen based on durability needs, cost considerations, and appearance preferences.