Pig Iron is an intermediate iron product produced during the smelting of iron ore in a blast furnace. It contains high carbon content (3.5%–4.5%) along with silicon, manganese, sulfur, and phosphorus.
Due to its brittle nature, pig iron cannot be used directly for structural applications. Instead, it serves as the primary raw material for steelmaking, cast iron, ductile iron, and various foundry products.
The name “Pig Iron” originates from the traditional casting method where molten iron solidified in branching molds resembling piglets suckling a sow.
Chemical Composition
| Element | Typical Range (%) |
|---|---|
| Iron (Fe) | 92 – 95 |
| Carbon (C) | 3.5 – 4.5 |
| Silicon (Si) | 0.5 – 3.0 |
| Manganese (Mn) | 0.3 – 1.5 |
| Phosphorus (P) | 0.05 – 1.0 |
| Sulfur (S) | 0.02 – 0.15 |
Key Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 100 – 200 MPa |
| Compressive Strength | High |
| Hardness | 200 – 350 HB |
| Elongation | ~0% (Brittle) |
| Impact Resistance | Very Low |
| Machinability | Poor |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.0 – 7.2 g/cm³ |
| Melting Point | 1,150 – 1,200°C |
| Thermal Conductivity | ~55 W/m·K |
| Electrical Conductivity | Low |
| Crystal Structure | Ferrite + Cementite |
Key Characteristics
High carbon content improves melt fluidity and lowers melting temperature, making pig iron ideal for casting and alloy control.
Pig iron provides predictable metallurgical input with consistent carbon and silicon levels, simplifying steelmaking and foundry operations.
Its brittle nature makes it unsuitable for fabrication and deformation, and it is intended strictly for remelting and refining.
Available Forms
Pig iron blocks (“pigs”)
Broken pig iron
Granulated pig iron
Foundry-grade pig iron
Steelmaking-grade pig iron
Low-phosphorus pig iron
Typical pig weight ranges between 20–45 kg per piece.
Applications of Pig Iron
Steel manufacturing – carbon steel and alloy steel production
Cast iron production – grey, ductile, and malleable iron
Foundry industry – automotive parts, engine blocks, pipes
Metallurgical additive – carbon, silicon, and manganese correction
Advantages of Pig Iron
✔ High carbon content for precise alloy control
✔ Excellent casting fluidity
✔ Consistent chemical composition
✔ Lower melting temperature than steel
✔ Cost-effective iron source
✔ Compatible with all melting furnaces
Limitations
❌ Extremely brittle
❌ No ductility
❌ Cannot be machined or welded
❌ Not a finished material
Why Choose Pig Iron?
Pig iron is selected when metallurgical control, casting quality, and cost efficiency are critical.
It ensures precise carbon and silicon input, reduces melting energy, improves casting surface finish, and enhances steelmaking consistency.