What is electro-galvanised steel sheet GA? Structure, SECC – GA standards and industrial applications
1. What is Electro Galvanized Steel? Concept according to metallurgy and electro-galvanised technology
Electro Galvanized Steel is a type of cold-rolled steel coated with a galvanised layer by the electro-galvanised method (Electro Galvanizing) to increase corrosion resistance, improve the metal surface, and enhance dimensional accuracy. This material is widely used in precision mechanics, elevators, electrical cabinets, industrial equipment, metal furniture, and industries requiring beautiful surfaces and small tolerances.
In the steel industry, Electro Galvanized Steel is often called by various names such as:
- Electro Galvanized Steel
- GA steel sheet
- SECC steel sheet
- electro-galvanised steel
- Electro Galvanized Steel
- Electro Zinc Steel
Although there are many different names, the essence of this material is still cold-rolled steel coated with a galvanised layer by the electro-galvanised method instead of the hot-dip method like conventional galvanised steel sheet.
1.1 Origin of Electro Galvanized Steel
Electro-galvanised steel sheet was developed to meet the demand for steel with a beautiful surface, high accuracy, and moderate rust resistance in indoor environments or not overly harsh environments.
While hot-dip galvanised steel sheet has a thick coating layer and good outdoor durability, the coating layer of the hot-dip method often has an uneven surface, spangles, and larger dimensional tolerance.
Therefore, in industries such as elevators, electrical cabinets, mechanical equipment, metal furniture manufacturing, a type of steel is required that is:
- Smooth surface
- Precise thickness
- Easy to paint
- Easy to form
- Easy to CNC fabricate
Therefore, electro-galvanised technology was developed to create a type of steel with a thin, uniform coating layer and very high accuracy.
1.2 Principle of electro-galvanised technology (Electro Galvanizing)
The electro-galvanised process is a process that uses electric current to deposit metal ions from an electrolytic solution onto the steel surface.
In this process:
- Cold-rolled steel is cleaned of oil and oxides
- Steel is placed into an electrolytic bath containing galvanised ions
- Electric current is passed through the solution
- Galvanised ions adhere uniformly to the steel surface
- Forming a thin and uniform galvanised coating
Because the coating layer is created by electric current, the coating thickness can be controlled very precisely, usually only a few micrometers but very uniform across the entire surface.
This is an important difference compared to hot-dip galvanising, where the galvanised layer is applied by dipping steel into a molten galvanised bath.
1.3 Why is it called Electro Galvanized Steel / GA steel sheet?
After electro-galvanising, the steel surface has a characteristic bright grey color, without large spangles like hot-dip galvanised steel sheet. This color gives the impression of a fine matte finish, so in practice the market often calls it GA steel sheet.
The grey color of electro-galvanised steel sheet is a result of the thin galvanised layer and the post-galvanising surface treatment, which may include:
- Anti-oxidation treatment
- Anti-fingerprint treatment
- Paint adhesion enhancement treatment
- Light corrosion resistance treatment
Thanks to its smooth and uniform surface, Electro Galvanized Steel is very suitable for products requiring high aesthetics or needing paint coating after fabrication.
1.4 Difference between electro-galvanised steel sheet and hot-dip galvanised steel sheet
Many people confuse electro-galvanised steel sheet and conventional galvanised steel sheet, however, these two types have completely different production technologies.
- Electro-galvanised steel sheet: thin coating layer, beautiful surface, high accuracy
- Hot-dip galvanised steel sheet: thick coating layer, good rust resistance, surface with spangles
Electro-galvanised steel sheet is often used for:
- Elevators
- Electrical cabinets
- Mechanical equipment
- Metal furniture
- CNC fabrication
Hot-dip galvanised steel sheet is often used for:
- Roofing
- Steel structures
- Workshops
- Outdoor construction projects
1.5 Common standards for electro-galvanised steel sheet
Electro Galvanized Steel is often produced according to international standards, among which the most common are:
- SECC – Steel Electro Coated Cold
- GA – Galvannealed
- SPCC + Electro Zinc
- JIS G3313
- ASTM A879
Each standard specifies the coating thickness, steel hardness, coating adhesion, and corrosion resistance.
Choosing the correct standard is very important in industries requiring high accuracy such as elevators, electrical cabinets, precision mechanics, industrial equipment.
2. Structure of Electro Galvanized Steel
Electro Galvanized Steel consists of 3 main layers:
Cold-rolled steel base layer
The steel base layer is produced using cold-rolled technology, has high flatness, small tolerance, and good durability.
Electrolytic galvanised coating
The galvanised layer is applied by electric current, which helps:
- Rust prevention
- Increase durability
- Increase paint adhesion
- Beautiful surface
Surface treatment layer
The surface can be treated for anti-oxidation or anti-fingerprint.
Illustration: Structure of electro-galvanised steel
3. Distinguishing SECC – GA – SGCC
| SECC | GA | SGCC |
| Electro-galvanised | Zinc alloy coating | Hot-dip galvanised |
| Smooth surface | Better rust resistance | Thick coating |
| Used for precision mechanics | Used for automotive, industrial | Used for construction |
4. Advantages of GA electro-galvanised steel sheet
Aesthetic surface
Suitable for elevator, electrical cabinet, furniture manufacturing.
High precision
Suitable for CNC cutting, laser cutting, bending.
Good rust resistance
Long lifespan in indoor environments.
Easy fabrication
Easy to press, bend, stamp.
5. Disadvantages
- Coating thinner than galvanised
- Not suitable for long-term outdoor use
- Higher price than regular steel sheet
6. Applications of GA electro-galvanised steel sheet
Elevators
Electrical cabinets
Industrial equipment
Metal furniture
Precision mechanics
VIEW GA ELECTRO-GALVANISED STEEL SHEET PRODUCT DETAILS HERE:
7. Common standards
- SECC
- GA
- SPCC + Electro zinc
- JIS
- ASTM
8. Notes when choosing GA electro-galvanised steel sheet
- Choose correct thickness
- Check surface
- Choose correct width
- Choose a supplier with fabrication services
Phu Cuong Steel Sheet – Leading Reputable Large Width Steel Sheet Distributor
Phu Cuong Steel Sheet specializes in supplying GA electro-galvanised steel sheet, GA steel sheet, galvanised steel sheet, large width steel sheet with full specifications, correct thickness, and correct standards.
Warehouse always has many sizes available, especially large widths from 1500mm to reduce material waste.
On-site fabrication workshop with modern coil slitting, cutting, and stamping machines.
Proactive truck delivery in Ho Chi Minh City and provinces.
- Address: 2177C–2177D QL1A, Dong Hung Thuan Ward, District 12, Ho Chi Minh City
- Phone: 0933 919 899
- Email: tonthepphucuong@gmail.com
- Website: tonthepphucuong.com
VIEW GA ELECTRO-GALVANISED STEEL SHEET PRODUCT DETAILS HERE:
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