DC04 Steel
DC04 is a high-quality cold-rolled low-carbon steel renowned for its exceptional formability, making it ideal for complex deep-drawing applications. As part of the European EN standard cold-rolled steel series, it offers superior ductility and surface quality compared to lower-grade cold-rolled steels (e.g., DC01), making it a preferred choice for industries requiring precise, intricate metal components.
Basic Information
Definition: DC04 is a non-alloy, dead-soft cold-rolled steel with ultra-low carbon content, engineered for demanding forming processes like deep drawing and stretch forming. Its cold-rolled production ensures a smooth surface finish, tight dimensional tolerance, and uniform mechanical properties.
Corresponding Standards: Complies with EN 10130:2006 (Cold rolled low carbon steel flat products for cold forming). International equivalents include:
China: Q195L (cold-rolled, deep-drawing grade)
USA: ASTM A1008 DS Type B (Deep Drawing)
Japan: JIS SPCE
Key Characteristics: Excellent deep drawability, high elongation, minimal work hardening, and a smooth surface, making it suitable for complex shapes with tight radii.
Chemical Composition
DC04’s composition is meticulously controlled to maximize formability, with ultra-low carbon and impurities:
Element Content Range Role in the Steel
Carbon (C) ≤0.08% Ultra-low content ensures maximum ductility and minimizes work hardening during deep drawing.
Manganese (Mn) ≤0.45% Moderate content improves strength slightly without compromising formability.
Silicon (Si) ≤0.03% Strictly limited to avoid surface defects and ensure a clean, smooth finish.
Phosphorus (P) ≤0.025% Reduced to prevent brittleness, critical for maintaining ductility in welded or formed parts.
Sulfur (S) ≤0.025% Minimized to avoid hot shortness and improve surface quality, especially in deep draws.
Aluminum (Al) ≥0.015% Acts as a deoxidizer, refining grain structure to enhance formability and toughness.
Physical Properties
Density: ~7.85 g/cm³ (standard for carbon steels).
Melting Point: ~1430–1450°C.
Thermal Conductivity: ~50 W/(m·K) at room temperature (good heat transfer).
Coefficient of Thermal Expansion: ~12×10⁻⁶/°C (20–100°C), typical for low-carbon steels.
Electrical Resistivity: ~0.16 μΩ·m (moderate conductivity).
Mechanical Properties
DC04’s properties are optimized for extreme formability, with emphasis on elongation and low yield strength:
Property Value Range (Cold-Rolled State)
Tensile Strength (Rm) 270–350 MPa
Yield Strength (Rp0.2) 120–200 MPa
Elongation (A80mm) ≥34%
Hardness ≤120 HV
Formability Metrics:
n-Value (Strain Hardening Exponent): ≥0.22 (high, indicating resistance to localized necking during drawing).
r-Value (Plastic Anisotropy Ratio): ≥1.4 (high, reducing thickness variation in deep-drawn parts).
Work Hardening: Minimal, allowing multiple forming steps without intermediate annealing.
Weldability: Excellent—easily welded with standard methods (spot welding, arc welding) without preheating.
Processing Performance
Deep Drawing: DC04 excels in deep drawing, producing parts with high depth-to-diameter ratios (e.g., cylindrical or box-shaped components) without cracking. Its low yield strength and high elongation prevent thinning or tearing in critical areas.
Stretch Forming: Suitable for complex shapes requiring uniform stretching (e.g., curved panels), thanks to its balanced r-value and n-value.
Bending: Can be bent to very tight radii (≤0.5× thickness) without fracturing, ideal for intricate folds.
Surface Treatment: Accepts painting, galvanizing, and plating exceptionally well due to its smooth, defect-free surface.
Machinability: Good for simple cutting operations, though its softness may require sharp tools to avoid deformation.
Application Fields
DC04 is the material of choice for complex formed components where precision and surface quality are critical:
Automotive Industry:
Fuel tanks, oil pans, and other deep-drawn fluid containers.
Interior trim panels, door handles, and dashboard components with intricate shapes.
Home Appliances:
Washing machine drums, refrigerator liners, and dishwasher tanks (deep-drawn, corrosion-prone parts).
Smaller components like valve housings and control knobs.
Consumer Electronics:
Enclosures for devices requiring tight tolerances and smooth finishes (e.g., audio equipment, small appliances).
Medical Devices:
Metal casings and components requiring precise forming and clean surfaces (e.g., instrument housings).
General Fabrication:
Lighting fixtures, decorative metal parts, and containers with complex geometries.
Advantages and Limitations
Advantages
Superior Formability: Handles deep drawing and complex shapes better than lower grades (DC01/DC03).
Surface Quality: Smooth, uniform finish reduces post-processing needs.
Dimensional Precision: Tight tolerances from cold rolling ensure consistency in mass production.
Cost-Effective: More affordable than specialty alloys while offering high performance for forming.
Limitations
Low Strength: Not suitable for structural or load-bearing applications.
Corrosion Susceptibility: Requires coating (galvanizing, painting) for outdoor or humid environments.
Wear Resistance: Soft nature makes it prone to abrasion; not ideal for moving parts.
In summary, DC04 steel is a high-performance cold-rolled grade designed for demanding forming applications, offering an unbeatable combination of formability, surface quality, and cost-effectiveness. Its ability to produce complex shapes reliably makes it indispensable in industries requiring precision metal components.