Galvanized steel sheet
Electro-galvanized steel sheet is widely used in industries that require a balance between corrosion resistance, surface quality, and excellent formability. Among these products, SECC+Z electro-galvanized steel sheet with 25/25g zinc coating and phosphated surface treatment is one of the most commonly specified materials for precision manufacturing and export-oriented projects.
This article provides a detailed technical overview of SECC+Z 25/25g phosphated electro-galvanized steel sheet, focusing on its coating structure, mechanical performance, and commonly supplied sizes such as 1.2mm × 1250mm and 1.5mm × 1250mm.
1. Overview of SECC+Z Electro-Galvanized Steel Sheet
SECC is a cold-rolled low-carbon steel grade that has been electro-galvanized to enhance corrosion resistance while maintaining high dimensional accuracy. Unlike hot-dip galvanized steel, electro-galvanized steel is produced through an electrolytic process that deposits zinc evenly across the steel surface.
The designation "+Z" indicates that a zinc coating is applied. Electro-galvanized zinc layers are thinner and more uniform than hot-dip coatings, making SECC+Z particularly suitable for applications requiring smooth surfaces and precise tolerances.
Key characteristics of SECC+Z electro-galvanized steel sheet include:
- Uniform zinc coating thickness
- Smooth and clean surface appearance
- Excellent formability and bendability
- Consistent quality for mass production
2. Understanding the 25/25g Zinc Coating Specification
The 25/25g designation refers to a double-sided zinc coating, with 25 g/m² applied to each side, resulting in a total coating weight of 50 g/m².
Zinc Coating Data Table
| Item | Specification |
|---|---|
| Coating method | Electro-galvanizing |
| Zinc coating structure | Double-sided |
| Zinc coating (per side) | 25 g/m² |
| Total zinc coating | 50 g/m² |
| Surface condition | Phosphated |
| Visual appearance | Smooth, uniform, no spangle |
This coating level provides reliable corrosion protection in indoor and mildly corrosive environments, making it an economical and practical solution for enclosed equipment and structural components.
3. Role of Phosphated Surface Treatment
Phosphating is a chemical surface treatment applied after electro-galvanizing. It forms a thin crystalline phosphate layer on top of the zinc coating, delivering several functional advantages.
Benefits of phosphated electro-galvanized steel include:
- Improved paint and powder coating adhesion
- Enhanced resistance to white rust during storage and transport
- Better welding consistency
- Reduced fingerprint visibility
Performance Comparison: With vs. Without Phosphating
| Performance Aspect | Non-Phosphated | Phosphated |
|---|---|---|
| Paint adhesion | Standard | Significantly improved |
| Surface uniformity | Normal | More consistent |
| Temporary corrosion resistance | Limited | Enhanced |
| Weld stability | Normal | Improved |
For manufacturers planning secondary processing such as painting or powder coating, phosphated SECC+Z steel sheet offers a clear technical advantage.
4. Standard Sizes: 1.2mm × 1250mm and 1.5mm × 1250mm
The width 1250mm is a widely accepted international standard, compatible with automated cutting, stamping, and forming lines. Combined with thicknesses of 1.2mm and 1.5mm, these sizes offer flexibility across multiple applications.
Common Size and Application Table
| Thickness (mm) | Width (mm) | Typical Applications |
|---|---|---|
| 1.2 | 1250 | Appliance housings, electrical enclosures |
| 1.5 | 1250 | Equipment panels, structural sheet metal |
These dimensions help optimize material utilization while ensuring sufficient strength and rigidity.
5. Typical Applications of SECC+Z 25/25g Steel Sheet
Due to its balanced performance, SECC+Z phosphated electro-galvanized steel sheet is widely used in:
- Home appliance inner and outer panels
- Electrical control cabinets
- Precision sheet-metal components
- Electronic equipment enclosures
- Indoor machinery and support structures
Its stable quality makes it a preferred choice for long-term export projects and standardized manufacturing.
SECC+Z 25/25g phosphated electro-galvanized steel sheet offers an ideal combination of corrosion resistance, surface quality, and processing performance. With commonly supplied sizes such as 1.2mm × 1250mm and 1.5mm × 1250mm, it meets the demands of precision manufacturing while maintaining cost efficiency.
