What is DC04EK Enameling Steel?
If you need extra deep drawing performance combined with superior vitreous enameling characteristics, DC04EK is the premium grade you should consider.
DC04EK is a cold-rolled low carbon steel specifically optimized for traditional enamel coating (EK suffix) with stamping level 04 (extra deep drawing). Compared with DC01EK and DC03EK, it offers even lower carbon (≤0.06%), stricter phosphorus/sulfur limits, and higher elongation, ensuring excellent enamel adhesion and reduced fish-scale defects for complex deep-drawn parts.
When you use DC04EK, you benefit from superior formability for the most demanding part geometries, consistent surface quality after firing, and minimal rejects due to blistering, poor adhesion, or fish scaling.
Typical applications include household enamelware, water heater liners, sanitary ware, bathtubs, oven cavities, and complex deep-drawn enamel components. If you need both extreme drawability and a flawless enamel finish, DC04EK gives you the highest performance foundation.
According to GB/T 13790—2025 Cold rolled low carbon steel sheet and strip for vitreous enamelling Supersedes GB/T 13790—2008 / GB/T 29515—2013
Technical Data Sheet — Grade DC04EK (Traditional Enameling Process / Extra Deep Drawing Quality)
📌 Designation System Clause 4.2
DC04EK consists of four parts:
- D — Steel flat product for cold forming
- C — Cold rolled condition
- 04 — Stamping level: Extra deep drawing (Level 04)
- EK — Enamelling type: Suitable for traditional enameling process
📖 Note: "ED" suffix indicates direct-on enameling process (also suitable for traditional), while DC04EK uses "EK" for traditional enameling with premium extra deep drawability.
📊 DC04EK vs Other Enameling Grades – Why Choose DC04EK?
1️⃣ vs DC01EK
DC01EK: General purpose stamping
DC04EK: Extra deep drawing – lower yield strength, much higher elongation
Carbon ≤0.06% vs ≤0.07% – better formability
Elongation ≥32-36% vs ≥26-30%
2️⃣ vs DC03EK
DC03EK: Drawing quality (C ≤0.07%)
DC04EK: Extra deep drawing – even lower carbon, higher elongation
Yield strength: ≤220 MPa (t>0.70mm) vs ≤240 MPa
Elongation: up to 36% vs up to 34%
3️⃣ Key Advantages
- Highest elongation (≥36% for t>0.70mm)
- Lowest carbon (≤0.06%) for formability
- Plastic strain ratio r90 ≥1.7
- 6-month stretcher strain free (FC/FD)
- Hydrogen permeation validated (TH ≥6.7)
💡 Key takeaway: DC04EK delivers the highest formability among EK-series enameling steels. Choose DC04EK when your part requires the most complex deep drawing geometries while maintaining superior enamel adhesion and fish-scale resistance.
🏺 Enameling Performance
🎯 Designed for
- Traditional two-coat enameling
- Complex extra deep-drawn components
- Reduced fish-scale & blistering
✨ Key Characteristics
- Excellent enamel adhesion
- Proven fish-scale resistance (TH ≥6.7)
- Superior extra deep drawing capability
- Lowest carbon (≤0.06%) for surface quality
⚙️ What makes DC04EK the premium enameling steel? Its ultra-low carbon chemistry (≤0.06%) and lowest P/S limits deliver consistent surface quality and exceptional formability. The hydrogen permeation test validates fish scale resistance (TH ≥6.7 min/mm²), while the highest elongation (up to 36%) enables the most complex deep-drawn shapes without cracking.
⚙️ Chemical Composition Clause 7.1 – Table 5 (Ladle analysis)
| Grade | C (%) | Mn (%) | P (%) | S (%) | Als (%) | Ti (%) |
|---|---|---|---|---|---|---|
| DC04EK | ≤0.06 | ≤0.50 | ≤0.025 | ≤0.030 | ≥0.010 | — |
🔬 Permissible deviations for product analysis according to GB/T 222 (Clause 7.1.2). Lower carbon (≤0.06%) and lower P/S enhance extra deep drawability and enamel adhesion.
📊 Mechanical Properties Clause 7.2 – Table 6
✅ Guarantee period: 6 months from manufacture date (7.2.1).
⚠️ Aging effect: yield & tensile strength may increase over time, elongation decreases – recommend early use (7.2.2).
⚠️ Aging effect: yield & tensile strength may increase over time, elongation decreases – recommend early use (7.2.2).
| Grade | ReL (MPa) ≤0.50mm |
ReL (MPa) >0.50~0.70 |
ReL (MPa) >0.70mm |
Rm (MPa) | A80mm (%) ≤0.50mm |
A80mm (%) >0.50~0.70 |
A80mm (%) >0.70mm |
|---|---|---|---|---|---|---|---|
| DC04EK | ≤260 | ≤240 | ≤220 | 270~350 | ≥32 | ≥34 | ≥36 |
📐 When yield phenomenon not obvious, use Rp0.2. 🔧 Lower yield strength limit of 140 MPa negotiable. 🧪 P6 transverse specimen. Plastic strain ratio r90 ≥1.7 (for thickness ≥0.50mm per Table 6).
📏 Stretcher Strain Clause 7.3 – Table 7
| Grade | Stretcher strain requirements |
|---|---|
| DC04EK (and DC01EK, DC03EK, DC05EK, DC03ED, DC04ED) | ✔️ For surface quality levels FC and FD, under room temperature storage, no stretcher strains within 6 months from manufacture date. |
| DC06EK, DC07EK, DC06ED | No stretcher strains shall appear under room temperature storage. |
📋 Enamelability Requirements Clauses 7.1.2 – 7.4.3
- 7.1.2 – Permissible deviations for product chemical analysis shall comply with GB/T 222.
- 7.2.1 – Mechanical properties guaranteed for 6 months from manufacture date as per Table 6.
- 7.2.2 – Due to aging effects, properties may change over time; early use is recommended.
- 7.3.1 – Skin-passing is applied, but stretcher strain tendency may reappear; recommend prompt use.
- 7.3.2 / Table 7 – For surface quality FC/FD, no stretcher strains within 6 months under room temperature storage.
- 7.4.1 – Hydrogen permeation test may be carried out upon agreement to evaluate fish-scale resistance.
- 7.4.2 – Adhesion test may be performed upon agreement; pretreatment and enameling conditions shall be stated in contract.
- 7.4.3 – Enamelability evaluation tests are recommended for first-time use or when enamel frit/process changes.
🔬 7.4.1 Anti-fishscale (Hydrogen permeation test)
Upon agreement, hydrogen permeation test (Annex B) may be carried out. Acceptance criteria by agreement.
📍 TH = tb/d² ; Electrolyte A: TH ≥ 6.7 min/mm². Electrolyte B: TH ≥ 6.7 min/mm² (negotiable for B/Ti steels).
🧪 7.4.2 Enamel adhesion test
Upon agreement, adhesion test may be performed. Pretreatment and enameling conditions shall be stated in contract.
🔄 7.4.3 Enamelability evaluation test
When using material first time or enamel frit/process changes, evaluation tests are recommended.
📋 Additional Technical Requirements
Surface quality (Table 8)
FB/FC/FD available. For FC/FD: stretcher strain free 6 months. No cracks, blisters, folds.
FB/FC/FD available. For FC/FD: stretcher strain free 6 months. No cracks, blisters, folds.
Oiling & rust (7.7)
Usually oiled, 6-month rust protection. Non-oiled: supplier not liable for rust/scratches.
Usually oiled, 6-month rust protection. Non-oiled: supplier not liable for rust/scratches.
📌 Surface texture: Dull Ra 0.6–1.9μm; Rough Ra >1.6μm (7.6). Dimensions per GB/T 708 (7.8). Plastic strain ratio r90 ≥1.7 for thickness ≥0.50mm (Table 6).
🏭 Manufacturing & Inspection
6.2 Annealed + skin-passed | 9.2 Batch ≤30t | 8.2 Tensile 1/batch | 10 Inspection doc type 3.1
📖 International grade comparison (Annex A)
GB/T 13790—2025: DC04EK ≈ EN 10209:2023 DC04EK, ISO 5001:2012 VE03 Type 1.
GB/T 13790—2025: DC04EK ≈ EN 10209:2023 DC04EK, ISO 5001:2012 VE03 Type 1.
🧪 Hydrogen Permeation Test Annex B
Thickness 0.50–3.00mm. TH = tb/d² ≥ 6.7 min/mm² (Electrolyte A). For B/Ti steels, results negotiable. DC04EK is designed to pass anti-fishscale criteria with consistent performance.
✅ Why specifiers choose DC04EK enameling steel
- Lowest carbon & low P/S (C≤0.06%, P≤0.025%, S≤0.030%) – cleanest surface, fewest enamel defects
- Premium extra deep drawing performance – yield strength as low as 220 MPa, elongation up to 36%
- Fish scale resistance – validated by hydrogen permeation test (TH ≥6.7 min/mm²)
- Plastic strain ratio r90 ≥1.7 for superior deep drawability
- 6-month mechanical property guarantee from manufacture date
- No stretcher strains for FC/FD surface quality within 6 months
- Hydrogen permeation / adhesion tests available upon agreement
- Oiled option: 6-month rust protection
Based on GB/T 13790—2025. Actual delivery subject to contract. Data verified per standard Tables 5, 6, 7 and Annex B.