Galvanized Sheet: Technical Specifications & Industrial Applications
Material Definition
Electrogalvanized (EG) steel sheet is a cold-rolled carbon steel product coated with a zinc layer (5-30 μm) through electrolytic deposition. This process preserves the base metal’s mechanical properties (YS: 140-550 MPa, TS: 270-600 MPa) while enhancing corrosion resistance (500-1,000 hrs salt spray test compliance).
Manufacturing Process Overview
- Surface Preparation
- Alkaline degreasing (NaOH 50-100g/L, 60-80°C)
- Acid pickling (HCl 10-20%, ambient temp) for oxide removal
- Electrodeposition
- Zinc electrolyte bath (ZnSO₄·7H₂O 200-400g/L, pH 4.5-5.5)
- Current density: 10-50 A/dm²
- Deposition rate: 0.5-2.5 μm/min
- Post-Treatment
- Chromate passivation (Cr³+ 0.5-3g/L) for enhanced corrosion resistance
- Oiling/anti-fingerprint treatment for storage protection
Material Classification System
| Base Steel Grade (JIS G 3141) | Electrogalvanized Designation | Typical Application |
|---|---|---|
| SPCC (Commercial Quality) | SECC | General fabrication |
| SPCD (Drawing Quality) | SECD | Automotive panels |
| SPCE (Deep Drawing) | SECE | Appliance housings |
| SPCF (Extra Deep Drawing) | SECF | Complex stampings |
Key Performance Metrics
- Coating Adhesion: ≥60N/cm (ISO 2409 cross-cut test)
- Surface Roughness: Ra 0.4-1.5μm (controlled via roller texture)
- Formability:
- Minimum bending radius: 0.5t (t=sheet thickness)
- Erichsen cupping value: 8.0-10.5mm
Industrial Applications
1. Construction & Architecture
- Structural Components:
- Light gauge steel framing (0.5-2.0mm thickness)
- Roofing/wall cladding (AZ100-AZ200 coating weights)
- Advantages:
- 3-5x longer service life vs. non-coated steel in C2-C4 environments
- Pre-painted substrate for PVDF/PE coatings
2. Automotive Engineering
- Critical Components:
- Body-in-white parts (door inners, floor panels)
- Chassis reinforcements (0.7-1.5mm SECC/SECD)
- Performance Benefits:
- 8-12μm coating prevents red rust for 5-8 years
- Compatible with e-coat cathodic electrodeposition
3. Appliance Manufacturing
- Core Applications:
- Refrigerator liners (0.6-1.2mm SECE)
- Washing machine drums (1.0-2.0mm SECC)
- HVAC ductwork (0.5-1.0mm SECD)
- Technical Requirements:
- Surface defects ≤Class B (EN 10163)
- Flatness tolerance ±1mm/m
4. Specialty Applications
- Electrical Enclosures: Zinc-iron alloy coatings (10-15% Fe) for EMI shielding
- Solar Mounting Systems: SECC-SV (severe environment grade) with 20μm minimum coating
Quality Control Parameters
- Coating uniformity: ±5% thickness variation (EDXRF measurement)
- Spangle size control: Minimized via Zn bath additives (Sb, Sn)
- Hydrogen embrittlement prevention: 200°C/2hrs baking for high-strength grades
Available in coil (ID 508/610mm, OD 1,200-1,500mm) or cut sheets (1,000×2,000mm to 1,500×3,000mm). Custom zinc-nickel (Zn-Ni 10-15%) alloy coatings available for marine environments.
Product Parameters
| Product Name | Hot Dip Galvanized Sheet |
| Thickness | 0.12mm-6.00mm |
| Width | 600mm-1500mm |
| Length | 1m-12m, Support Customization |
| Standard | AISI, ASTM, DIN, JIS, GB, JIS, SUS, EN, etc. |
| Zinc Layer | Hot Galvanizing: 60-275g/m² |
| Pre-galvanized: 80-275g/m² |
Chemical Composition
| Standard | Grade | C | Si | Mn | P | S | Ti |
| Forcold Forming
Chinese Standard |
DX51D+Z | 0.12 | 0.50 | 0.60 | 0.100 | 0.045 | 0.30 |
| DX52D+Z | 0.12 | 0.50 | 0.60 | 0.100 | 0.045 | 0.30 | |
| DX53D+Z | 0.12 | 0.50 | 0.60 | 0.100 | 0.045 | 0.30 | |
| DX54D+Z | 0.12 | 0.50 | 0.60 | 0.100 | 0.045 | 0.30 | |
| DX56D+Z | 0.12 | 0.50 | 0.60 | 0.100 | 0.045 | 0.30 | |
| DX57D+Z | 0.12 | 0.50 | 0.60 | 0.100 | 0.045 | 0.30 | |
| Forcold Forming
Japanese Standard |
SGCC | 0.15 | 0.50 | 0.80 | 0.050 | 0.030 | 0.025 |
| SGCD1 SGCD2 |
0.12 0.10 |
0.50 0.50 |
0.60 0.45 |
0.040 0.030 |
0.030 0.030 |
0.025 0.025 |
|
| SGCD3 | 0.08 | 0.50 | 0.45 | 0.030 | 0.030 | 0.025 | |
| SGCD4 | 0.06 | 0.50 | 0.45 | 0.030 | 0.030 | 0.025 | |
| For Structure
Japanese Standard |
SGC340 | 0.25 | 0.50 | 1.70 | 0.200 | 0.035 | 0.025 |
| SGC400 SGC440 |
0.25 0.25 |
0.50 0.50 |
1.70 2.00 |
0.200 0.200 |
0.035 0.035 |
0.150 0.150 |
|
| SGC490 | 0.30 | 0.50 | 2.00 | 0.200 | 0.035 | 0.025 | |
| SGC510 | 0.30 | 0.50 | 2.50 | 0.200 | 0.035 | 0.025 | |
| For Structure
AISI Standard |
S220GD+Z | 0.20 | 0.60 | 0.70 | 0.100 | 0.045 | 0.025 |
| S250GD+Z | 0.20 | 0.60 | 0.70 | 0.100 | 0.045 | 0.025 | |
| S280GD+Z | 0.20 | 0.60 | 0.70 | 0.100 | 0.045 | 0.025 | |
| S320GD+Z | 0.20 | 0.60 | 0.70 | 0.100 | 0.045 | 0.025 | |
| S350GD+Z | 0.20 | 0.60 | 0.70 | 0.100 | 0.045 | 0.150 | |
| S550GD+Z | 0.20 | 0.60 | 0.70 | 0.100 | 0.045 | 0.150 |
Mechanical Properties
| Grade | Yield Strength MPa≥ | Tensile Strength MPa≥ | Elongation A%≥ |
| DX51D Z/ZM/AZ/AM | 240-380 | 270-500 | 22 |
| DX52D Z/ZM/AZ/AM | 140-300 | 270-420 | 26 |
| DX53D Z/ZM/AZ/AM | 140-260 | 270-380 | 30 |
| DX54D Z/ZM/AZ/AM | 120-220 | 260-350 | 36 |
| S220GD Z/ZM/AM | 220 | 300 | 20 |
| S250GD Z/ZM/AZ/AM | 250 | 330 | 19 |
| S280GD Z/ZM/AM | 280 | 360 | 18 |
| S300GD A/AM | 300 | 380 | 18 |
| S320GD Z/ZM/AM | 320 | 390 | 17 |
| S350GD Z/ZM/AZ/AM | 350 | 420 | 16 |
| S450GD A/AM | 450 | 480 | 15 |
| S550GD Z/ZM/AZ/AM | 550 | 550 | – |
Galvanized Surface Selection
| Use of The Environment | Recommended Zinc Thickness |
| Indoor Use | Z10 or Z12 (100g/㎡or 120g/㎡) |
| Suburbs | Z20 and Painting (200g/㎡) |
| Urban or Industrial Area | Z27 (270g/㎡) or G90 (US Standard) and painted |
| Coastal Area | Thicker than Z27 (270g/㎡) or G90 (US Standard) and painted |
| Punch or Deep Drawing Application | Thicker than Z27 (270grams/㎡) or G90 (US Standard) avoid coating peeling after stamping |
| Surface Treatment Type | Code | Features |
| Chromic Acid Treatment | C | Good corrosion resistance, suitable for bare state |
| Chromic Acid Treatment+Oiling | S | Good corrosion resistance |
| Phosphoric Acid Treatment (Including Sealing Treatment) | P | Have a certain corrosion resistance, good paint performance |
| Phosphoric Acid Treatment (Including Sealing Treatment)+Oiling | Q | Has a certain corrosion resistance, good paint performance, prevent rust during transportation and storage |
| Phosphoric Acid Treatment (Excluding Sealing Treatment) | T | Have a certain corrosion resistance, good paint performance |
| Phosphoric Acid Treatment (Excluding Sealing Treatment)+Oiling | V | Has a certain corrosion resistance, good paint performance, and prevent rust |
| Oiling | O | Prevent rust during transportation and storage |
| No Treatment | M | Suitable for immediate painting |
Material Comparison
|
Chinese Standard |
Japan Standard | European Standard |
| DX51D Z/DC51D Z (CR) | SGCC | DX51D Z |
| DX52D Z/DC52D Z | SGCD1 | DX52D With |
| DX53D Z/DC53D Z/DX54D Z/DC54D Z | SGCD2/SGCD3 | DX53D Z/DX54D Z |
| S220/250/280/320/350/550GD Z | SGC340/400/440/490/570 | S220/250/280/320/350GD Z |
| DX51D Z/DD51D Z (HR) | SGHC | DX51D Z |
Packing And Delivery
