SECD electro‑galvanized steel sheets
SECD electro‑galvanized steel sheets (JIS G3313, Drawing grade) are cold‑rolled low‑carbon steel substrates electrolytically coated with a uniform zinc layer, engineered for exceptional deep drawability, high surface quality, and reliable corrosion resistance. As a specialized grade above commercial‑grade SECC, SECD is the preferred material for complex stamped components in automotive, appliance, and electronics industries, delivering consistent performance in high‑volume production.
Core Definition
1.Grade Meaning: SECD = Steel Electrolytic Cold Drawing; the suffix "D" denotes deep‑drawing quality, with SPCD as the base cold‑rolled steel (low C, low P, stabilized annealing).
2.Substrate: Ultra‑low‑carbon cold‑rolled steel (C ≤ 0.08%, Mn ≤ 0.40%) with strict impurity control (S ≤ 0.03%, P ≤ 0.02%) to eliminate brittleness during extreme forming.
3.Electroplating: Continuous electrolytic deposition of pure zinc (Z) or zinc‑iron alloy (ZF) onto the substrate, producing a thin, dense, and uniform coating (typically 14–28 g/m² per side) with precise thickness control ±1 g/m².
4.Post‑Treatment: Optional chromate (Cr⁶⁺/Cr³⁺), phosphate, anti‑fingerprint (AFP), or oiled passivation to enhance corrosion resistance and paint adhesion.
SECD Specifications Table
SECD is optimized for plastic deformation without cracking, outperforming SECC in elongation and deep‑draw ratio.
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Available range of SECD electro-galvanized steel sheets for appliances:
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Item |
Nominal |
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Thickness |
0.3-3.5 |
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Width |
800-1830 |
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Length |
Steel plate |
1000-6000 |
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Steel strip |
Coil inside diameter 508,610 |
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SECD electro-galvanized coating range and recommended nominal coating weight:
Coating from |
Coating type |
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Pure zinc coating (single-side) g/m² |
Zinc-nickel alloy coating (single-side) g/m² |
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Uniform thickness |
3~90 |
10~40 |
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Different thickness |
3~90, the maximum difference value between both sides is 40. |
10~40, the maximum difference value between both sides is 20. |
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Single side |
10~110 |
10~40 |
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Note: The weight of 50g/m²of pure zinc coating is equal to about 7.1um, and the weight of 50g/m² of zinc-nickel alloy coating is equal to about 6.8um. |
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Get SECD Steel Specification Sheet
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Coating form |
Coating type |
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Pure zinc coating (single-side) g/m² |
Zinc-nickel alloy coating (single-side) g/m² |
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Uniform thickness |
10/10, 20/20, 30/30, 40/40, 50/50, 70/70, 90/90 |
10/10, 20/20, 30/30, 40/40 |
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Difference thickness |
10/30, 20/40, 30/50, 40/60, 50/70, 60/90 |
10/20, 15/25, 25/30, 30/40 |
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Single side |
10/0, 20/0, 30/0, 40/0, 50/0, 60/0, 70/0, 80/0, 90/0, 100/0, 110/0 |
10, 15, 20, 25, 30, 40 |
Get SECD Steel Specification Sheet
Surface Quality & Coating Characteristics
- Surface Finish: O5 (mirror) or O3 (bright) surfaces with Ra ≤ 0.8 μm; free of pinholes, scratches, or coating unevenness.
- Coating Uniformity: Zinc layer thickness variation ≤10% across the sheet, guaranteeing consistent corrosion protection and paint bonding.
- Corrosion Resistance: Electrochemical protection from zinc coating; 500+ hours of salt‑spray resistance (ASTM B117) with chromate treatment, 2× higher than bare cold‑rolled steel.
- Paintability: Excellent adhesion for powder coating, liquid painting, or silk‑screening; no primer required for most applications.
Standard Specifications
1. Standard: JIS G3313 (1998), ISO 3575, equivalent to ASTM A591/A879.
2. Thickness: 0.4 mm – 3.0 mm (tolerance ±0.03 mm).
3. Width: 914 mm – 1524 mm (1219 mm standard).
4. Coating Weight: Z14 (14 g/m²), Z20 (20 g/m²), Z28 (28 g/m²); ZF (zinc‑iron alloy) available for high‑corrosion environments.
5. Form: Sheets, coils, or slit strips; coil ID 508 mm / 610 mm.
Primary Applications
1.Automotive Industry
Door inner panels, trunk lids, and seat frames.
Fuel tank shells and wheel housings (complex deep‑drawn shapes).
Interior structural reinforcements and bracket components.
2.Home Appliances
Washing machine drums, microwave cavities, and refrigerator inner liners.
Air conditioner panels and water heater tanks (high hygiene & corrosion resistance).
3.Electronics & Electrical
Server chassis, computer cases, and control panels (EMI shielding + surface quality).
Battery enclosures and electrical cabinet doors.
4.General Hardware
Deep‑drawn kitchenware, lamp housings, and office furniture components.
SECD vs. SECC: Critical Differences
1. Formability: SECD (elongation 30%–42%) >> SECC (20%–25%); SECD handles 30% deeper draws without cracking.
2. Substrate Purity: SECD uses ultra‑low‑carbon steel with tighter impurity limits; SECC uses standard SPCC substrate.
3. Surface Consistency: SECD has zero aging marks for 3 months; SECC may develop stretcher strains within 1 month.
4. Cost‑Performance: SECD costs 8%–12% more than SECC but reduces scrap rates by 40%–60% in complex stamping, lowering total production costs.
SECD Galvanized Steel Coil
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GNEE can also supply the following product grades:
FAQ
What does SECD stand for in electro-galvanized steel?
SECD refers to Steel Electrolytic Cold Deep-drawing grade. It is a deep-drawing quality electro-galvanized steel defined under JIS G3313, specially developed for complex stamping and deep forming processes.
What are the main differences between SECD and SECC electro-galvanized steel?
SECD features higher elongation, better deep drawability and excellent anti-aging performance. It is suitable for intricate deep-drawn parts, while SECC is a commercial grade for simple forming applications.
What is the typical zinc coating weight of your SECD electro-galvanized sheets?
Our standard coating weights include Z14, Z20 and Z28 (g/m² per side). Zinc-iron alloy (ZF) coating and customized coating thickness are also available on request.
What surface treatments can be applied to SECD electro-galvanized steel?
We provide multiple options: chromate passivation, phosphate treatment, anti-fingerprint (AFP) coating and dry/oiled finish, to meet demands for corrosion resistance and painting performance.
What mechanical properties should I expect from SECD grade?
ts yield strength is below 280 MPa, tensile strength ranges from 300 MPa to 400 MPa, and the elongation reaches 39% or above, ensuring stable performance during deep drawing.
What industries commonly use SECD electro-galvanized steel sheets?
It is widely used for automotive parts, home appliance shells, electronic enclosures and hardware components that require superior formability and premium surface quality.
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