Aug 4, 2026Services Overview
Electro Galvanized Chains: Process, Quality & Applications
This guide explains how electro galvanizing works, how it compares to hot-dip galvanizing, and what to look for when sourcing electro galvanized chains.
Electro galvanizing is one of the most widely used surface finishes for industrial chains. It provides a bright, clean appearance with moderate corrosion protection at a competitive cost — making it the go-to choice for hardware retail, agricultural equipment, indoor conveyor systems, and general-purpose outdoor use.
What Is Electro Galvanizing?
Electro galvanizing, also called electroplating, deposits a thin, uniform layer of zinc onto the steel chain through an electrochemical process. Unlike hot-dip galvanizing — which immerses steel in molten zinc at around 450°C — electro galvanizing takes place at room temperature.
Key characteristics of electro galvanized chains:
- Bright, silver-white, uniform appearance
- Zinc coating typically 8–25 microns thick
- Moderate corrosion resistance — suitable for indoor and light outdoor use
- Cost-effective compared to hot-dip galvanizing
- Minimal dimensional change after plating
The Electro Galvanizing Process
Step 1: Surface Preparation
Before plating can begin, the chain surface must be completely free of oil, rust, and mill scale. This is the most critical step for coating adhesion.
Stage | What Happens |
|---|---|
Alkaline degreasing | Removes oils and lubricants from the chain surface |
Water rinse | Washes away residual chemicals |
Acid pickling | Removes rust and mill scale; activates the steel surface |
Final rinse | Ensures no acid remains before plating |
Because chains have interlocking links, the cleaning process must allow solutions to penetrate the tight contact points between links. Extended immersion times or barrel agitation are often used to ensure complete cleaning.
Step 2: Electroplating (Zinc Deposition)
The cleaned chain is immersed in a zinc-based electrolyte solution. A DC electric current is applied:
- The chain acts as the cathode (–), attracting zinc ions from the solution
- Pure zinc anodes (+) dissolve into the bath, replenishing the zinc supply
Common plating bath types used today:
Bath Type | Characteristics |
|---|---|
Acid chloride (potassium-based) | High efficiency, excellent brightness; most common for industrial chains |
Alkaline non-cyanide | Better throwing power for complex shapes; environmentally friendly |
Chains are typically plated in rotating barrels, which tumble the links continuously. This ensures that even the contact points between adjacent links receive zinc coverage — a challenge unique to chain plating.
Step 3: Post-Treatment (Passivation)
After plating, the zinc layer is porous and can develop white rust in humid conditions. A passivation treatment is applied to seal the surface and enhance corrosion resistance.
Passivation Type | Appearance | Salt Spray Resistance |
|---|---|---|
Blue-white (Cr³⁺) | Bright silver-blue | 72–120 hours |
Yellow (Cr³⁺) | Golden iridescent | 120–200 hours |
Black (Cr³⁺) | Uniform black | 120–150 hours |
Environmental note: Trivalent chromium (Cr³⁺) passivation is now the industry standard, replacing hexavalent chromium (Cr⁶⁺) which is restricted under EU RoHS and REACH regulations.
Electro Galvanized vs. Hot-Dip Galvanized
Property | Electro Galvanized | Hot-Dip Galvanized |
|---|---|---|
Process temperature | Room temperature | ~450°C |
Zinc layer thickness | 8–25 microns | 50–80+ microns |
Appearance | Bright, smooth, uniform silver | Matte grey, slightly textured |
Corrosion resistance | Moderate — light outdoor use | Excellent — marine and heavy industrial |
Dimensional precision | Minimal change | Slight increase due to thick coating |
Cost | Lower | Higher |
Best application | Retail, indoor, light outdoor | Construction, marine, offshore |
When to choose electro galvanized: Your chain needs a clean, attractive appearance at a competitive price, and will be used indoors or in moderate outdoor conditions.
When to choose hot-dip galvanized: Your chain will face harsh outdoor exposure, saltwater, or heavy industrial use where maximum corrosion protection matters.
Common Applications
Sector | Why Electro Galvanized Is Used |
|---|---|
Hardware retail & DIY | Bright, shelf-ready appearance; cost-effective |
Agricultural equipment | Moderate outdoor protection at reasonable cost |
Indoor conveyors | Protection from humidity and condensation |
Security chains | Corrosion protection with visual appeal |
Playground equipment | Smooth surface, safe for contact |
General-purpose outdoor | Light to moderate weather exposure |
Quality Standards
Electro galvanized chains are typically manufactured to the following international standards:
Standard | What It Covers |
|---|---|
ISO 2081 | General specification for electroplated zinc coatings on steel |
ASTM B633 | Standard specification for electrodeposited zinc coatings |
DIN 50963 | Zinc coatings on steel — requirements and testing |
For industrial chains, a coating thickness of 12–25 microns is the most common range.
Frequently Asked Questions
Can electro galvanized chain be used outdoors?Yes, with proper passivation. For light outdoor use, 12–25 microns with yellow passivation offers good protection. For harsh outdoor or marine environments, hot-dip galvanized or stainless steel is recommended.
How long does electro galvanized chain last?Indoors: many years. Outdoors with passivation: 3–8 years depending on climate. Without passivation: significantly shorter.
What causes white powder on the chain surface?This is "white rust" — zinc corrosion caused by moisture exposure. It usually indicates insufficient passivation or poor storage conditions.
Can electro galvanized chains be re-plated?Yes, but the existing coating must be stripped first. For most applications, replacing the chain is more cost-effective.
Is Cr³⁺ passivation as effective as Cr⁶⁺?For most applications, yes. Cr³⁺ passivation offers comparable corrosion resistance and is the standard for markets requiring RoHS/REACH compliance.
Sourcing Electro Galvanized Chains
When specifying or ordering electro galvanized chain, confirm these points with your supplier:
- Zinc coating thickness (e.g., 12 microns minimum)
- Passivation type (Cr³⁺ blue-white is standard)
- Chain grade (G30, G43, G80, etc.)
- Packaging requirements (bulk, hanging cards, cartons, etc.)
- Applicable standards (ISO 2081, ASTM B633)
Boyuan Metal supplies electro galvanized chains in carbon steel, alloy steel, and stainless steel across multiple grades and sizes. Our standard finish uses Cr³⁺ eco-friendly passivation, compliant with EU RoHS and REACH requirements. Contact us to discuss your requirements or request a quotation.