SPCD: Cold-Rolled Low-Carbon Steel Sheet for Stamping
SPCD, as defined in the Japanese Industrial Standard (JIS G 3141), is a commercial-quality cold-rolled low-carbon steel sheet optimized for stamping and drawing applications. With its controlled carbon content and enhanced formability, SPCD offers superior ductility and surface quality, making it ideal for manufacturing automotive components, household appliances, and metal furniture. This article explores its chemical composition, mechanical properties, production processes, applications, and comparative advantages over related grades.
1. Core Chemical Composition (JIS G 3141 Standard)
| Element | Content Range | Function |
|---|---|---|
| Carbon (C) | ≤ 0.15% | Low content ensures high ductility and formability; minimizes hardening during cold working |
| Manganese (Mn) | ≤ 0.60% | Improves strength and toughness; aids in deoxidation and hot workability |
| Phosphorus (P) | ≤ 0.050% | Controlled to prevent brittleness and ensure consistent stamping performance |
| Sulfur (S) | ≤ 0.035% | Limited to avoid hot shortness and inclusions that could impair surface finish |
| Aluminum (Al) | ≥ 0.020% (as acid-soluble Al) | Acts as a deoxidizer; promotes fine grain structure for better deep drawing |
2. Key Mechanical Properties (Room Temperature)
- Tensile Strength (TS): 270-410 MPa (JIS G 3141 standard; provides adequate strength for structural forming)
- Yield Strength (YS): ≤ 240 MPa (low yield point supports extensive deformation without fracture)
- Elongation (EL): ≥ 36-38% (excellent for deep drawing and complex stamping operations)
- Hardness (HRB): ≤ 65 (Rockwell B; soft surface ideal for painting and coating adhesion)
- n-Value (Strain Hardening Exponent): ≥ 0.18 (indicates good uniform elongation during forming)
3. Manufacturing Process Characteristics
- Hot Rolling: Base hot-rolled coil produced from low-carbon steel via basic oxygen furnace (BOF) or electric arc furnace (EAF), with controlled finishing temperature (850-920°C) to ensure uniform microstructure.
- Pickling: Acid pickling (hydrochloric or sulfuric acid) to remove mill scale and surface oxides, preparing the strip for cold reduction.
- Cold Rolling: Multi-pass cold reduction (typically 50-80% total) to achieve final thickness (0.3-3.5 mm), with skin-pass rolling for improved flatness and surface texture.
- Annealing: Continuous annealing at 650-750°C in a controlled atmosphere to recrystallize the structure, restore ductility, and relieve internal stresses.
- Surface Treatment: Oiling with rust-preventive lubricant; optional chemical treatment for enhanced corrosion resistance during storage and transport.
4. Typical Application Fields
Automotive Industry
Body panels, fenders, wheel arches, and interior trim components — excels in deep drawing for complex shapes without cracking.
Household Appliances
Refrigerator shells, washing machine tubs, microwave oven exteriors, and range hoods — provides smooth surfaces for painting and enamel coating.
Furniture & Office Equipment
Metal cabinets, filing drawers, desk frames, and shelving — formable into precise shapes with good weldability.
General Manufacturing
Electrical enclosures, HVAC ducting, and stamped brackets — cost-effective for medium to high-volume production.
5. Difference from Similar Grades (SPCD vs SPCC vs SPCE)
| Grade | Formability Level | Key Advantage | Suitable Scenario |
|---|---|---|---|
| SPCD | Drawing Quality | Balanced formability and strength; good for moderate drawing | Automotive panels, appliance housings with bending and shallow drawing |
| SPCC | Commercial Quality | Lower cost; basic formability for simple stamping | General fabrication, exposed or non-critical surfaces |
| SPCE | Deep Drawing Quality | Superior elongation and n-value for deep draws | Automotive fuel tanks, sinks, and parts requiring extensive deformation |
6. Selection & Usage Precautions
- Forming Limits: Suitable for drawing ratios up to 2.0; for deeper draws, consider SPCE to avoid earing or splitting.
- Surface Protection: Apply anti-corrosion coatings (e.g., zinc phosphate) post-forming; store in dry conditions to prevent rust during transit.
- Welding Compatibility: Excellent for resistance spot welding; use low-hydrogen electrodes for arc welding to minimize porosity.
- Thickness Selection: Thinner gauges (≤1.0 mm) for high-formability needs; verify with Erichsen cupping test for specific applications.
- Quality Assurance: Obtain material certificates confirming compliance with JIS G 3141; inspect for surface defects like slivers or laminations.
7. Get a Steel Quote
If you require customized SPCD cold-rolled steel sheets or coils, or need a detailed price quote for your project, contact our team. We offer professional guidance and competitive pricing tailored to your specifications.